Air pollution#Control devices

File:Athlone cooling towers demolition 2010-08-22.gif of the cooling towers of a power station, Athlone, Cape Town, South Africa, 2010|alt=Dust and debris rise as large concrete cooling towers collapse during a controlled demolition]]

File:Air pollution by industrial chimneys.jpg was installed, the emissions from this power plant in New Mexico contained excessive amounts of sulfur dioxide.|alt=A factory with chimneys releasing smoke.]]

The burning of fuels to produce electricity causes air pollution. Lignite and coal produce most air pollution, followed by oil. The burning of fossil gas and biomass causes less air pollution.{{Cite journal |last1=Markandya |first1=Anil |last2=Wilkinson |first2=Paul |date=2007-09-15 |title=Electricity generation and health |url=https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(07)61253-7/abstract |journal=The Lancet |language=English |volume=370 |issue=9591 |pages=979–990 |doi=10.1016/S0140-6736(07)61253-7 |issn=0140-6736 |pmid=17876910}}{{Cite journal |last=Ritchie |first=Hannah |date=2020-02-10 |title=What are the safest and cleanest sources of energy? |url=https://ourworldindata.org/safest-sources-of-energy |journal=Our World in Data |language=en}} Methane leaks are common in oil and gas production.{{cite news |last=Rannard |first=Georgina |date=4 February 2022 |title=Climate change: Satellites map huge methane plumes from oil and gas |url=https://www.bbc.com/news/science-environment-60203683 |access-date=16 March 2022 |work=BBC News}}{{cite journal |last1=Lauvaux |first1=T. |last2=Giron |first2=C. |last3=Mazzolini |first3=M. |last4=d'Aspremont |first4=A. |last5=Duren |first5=R. |last6=Cusworth |first6=D. |last7=Shindell |first7=D. |last8=Ciais |first8=P. |title=Global assessment of oil and gas methane ultra-emitters |journal=Science |date=4 February 2022 |volume=375 |issue=6580 |pages=557–561 |doi=10.1126/science.abj4351 |pmid=35113691 |arxiv=2105.06387 |bibcode=2022Sci...375..557L |s2cid=246530897 |issn=0036-8075 |url=https://www.science.org/doi/10.1126/science.abj4351 |url-access=subscription}}

Other industries cause air pollution too. A 2014 study found that in China, manufacturing and construction sectors contributed more than 50% of air pollution. This was due to high emission intensity and high emission factors in its industrial structure.{{Cite journal |last1=Huo |first1=Hong |last2=Zhang |first2=Qiang |last3=Guan |first3=Dabo |last4=Su |first4=Xin |last5=Zhao |first5=Hongyan |last6=He |first6=Kebin |date=2014-12-16 |title=Examining Air Pollution in China Using Production- And Consumption-Based Emissions Accounting Approaches |url=https://pubs.acs.org/doi/10.1021/es503959t |journal=Environmental Science & Technology |language=en |volume=48 |issue=24 |pages=14139–14147 |doi=10.1021/es503959t |pmid=25401750 |bibcode=2014EnST...4814139H |issn=0013-936X}} Polluting industries have been pushed out of richer nations, and China has also started to push its most polluting industries out of the country.{{Cite journal |last1=Aunan |first1=Kristin |last2=Hansen |first2=Mette Halskov |last3=Wang |first3=Shuxiao |date=2018 |title=Introduction: Air Pollution in China |url=https://www.cambridge.org/core/journals/china-quarterly/article/introduction-air-pollution-in-china/8D36F205FEC68513BC45E2DEC0F2AC26 |journal=The China Quarterly |language=en |volume=234 |pages=279–298 |doi=10.1017/S0305741017001369 |issn=0305-7410}}

Construction and demolition produces dust, but also other pollutants. The particles from construction and demolition are relatively coarse.{{Cite web |title=Emissions of air pollutants in the UK – Particulate matter (PM{{sub|10}} and PM{{sub|2.5}}) |url=https://www.gov.uk/government/statistics/emissions-of-air-pollutants/emissions-of-air-pollutants-in-the-uk-particulate-matter-pm10-and-pm25#major-emission-sources-for-pm10-and-pm25-in-the-uk |url-status=live |archive-url=https://web.archive.org/web/20230122102456/https://www.gov.uk/government/statistics/emissions-of-air-pollutants/emissions-of-air-pollutants-in-the-uk-particulate-matter-pm10-and-pm25#major-emission-sources-for-pm10-and-pm25-in-the-uk |archive-date=22 January 2023 |access-date=22 January 2023 |website= |publisher=DEFRA}}{{cite journal |last1=Azarmi |first1=Farhad |last2=Kumar |first2=Prashant |date=July 2016 |title=Ambient exposure to coarse and fine particle emissions from building demolition |journal=Atmospheric Environment |volume=137 |pages=62–79 |bibcode=2016AtmEn.137...62A |doi=10.1016/j.atmosenv.2016.04.029}} Though banned in many countries, asbestos persists in older buildings, where it poses a risk of lung disease when disturbed.{{Cite journal |last1=Caceres |first1=Jose Diego |last2=Venkata |first2=Anand N. |date=2023-03-01 |title=Asbestos-associated pulmonary disease |journal=Current Opinion in Pulmonary Medicine |volume=29 |issue=2 |pages=76–82 |doi=10.1097/MCP.0000000000000939 |issn=1531-6971 |pmid=36630203}} Building materials including carpeting and plywood emit formaldehyde, a gas which can cause difficulty breathing and nausea.{{Cite web |date=5 June 2015 |title=Taking an Exposure History: What Are Possible Sources of Indoor Air Pollution |url=https://www.atsdr.cdc.gov/csem/exposure-history/Indoor-Air-Pollution-Sources.html |url-status=dead |archive-url=https://web.archive.org/web/20241009071645/https://www.atsdr.cdc.gov/csem/exposure-history/Indoor-Air-Pollution-Sources.html |archive-date=9 October 2024 |access-date=2024-07-08 |website= |publisher=ATSDR, CDC |language=en-us}}{{Source-attribution}}

Road vehicles produce a significant amount of all air pollution. For instance, they may be responsible for a third to half of all nitrogen dioxide emissions,{{cite journal |vauthors=Wang J, Wu Q, Liu J, Yang H, Yin M, Chen S, etal |year=2019 |title=Vehicle emission and atmospheric pollution in China: problems, progress, and prospects. |journal=PeerJ |volume=7 |issue= |pages=e6932 |doi=10.7717/peerj.6932 |pmc=6526014 |pmid=31143547 |doi-access=free}}{{cite journal |author=Aggarwal P, Jain S |year=2015 |title=Impact of air pollutants from surface transport sources on human health: A modeling and epidemiological approach. |url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26142107 |journal=Environ Int |volume=83 |issue= |pages=146–57 |bibcode=2015EnInt..83..146A |doi=10.1016/j.envint.2015.06.010 |pmc= |pmid=26142107}} and are a major driver of climate change.{{Cite journal |last=Ritchie |first=Hannah |date=2020-10-06 |title=Cars, planes, trains: where do CO₂ emissions from transport come from? |url=https://ourworldindata.org/co2-emissions-from-transport |journal=Our World in Data |language=en}} Vehicles with petrol and diesel engines produce about half of their emissions from their exhaust gas, and the other half from non-exhaust emissions (tyre and brake wear and erosion or disturbance of the road surface); electric vehicles produce no tailpipe emissions, but still produce the other emissions.{{cite book |last1=Amato |first1=Fulvio |url=https://books.google.com/books?id=hSk0DwAAQBAJ |title=Non-Exhaust Emissions: An Urban Air Quality Problem for Public Health; Impact and Mitigation Measures |date=2018 |publisher=Academic Press |isbn=978-0-12-811770-5 |location=London, UK |page=4 |access-date=17 January 2025}} Diesel trains, ships and planes also cause air pollution.{{cite web |title=Overview of Air Pollution from Transportation |url=https://www.epa.gov/transportation-air-pollution-and-climate-change/overview-air-pollution-transportation |publisher=US Environmental Protection Agency |access-date=16 June 2022 |date=15 December 2021}}

File:BurningOffFieldsInTheEveningInSouthGeorgia.jpg of a field outside of Statesboro, Georgia, US, in preparation for spring planting|alt=Smoke rises from a fire, and is dispersed by wind]]

File:Agbogbloshie,_Ghana_2019.jpg, Ghana, using open-burning of electronics to access valuable metals like copper|alt=Several people are working on a heap of rubbish, with smoke rising from it.]]

Agricultural emissions and emissions from meat production or livestock contribute substantially to air pollution.{{cite journal |last1=Sun |first1=Feifei |last2=Dai |first2=Yun |last3=Yu |first3=Xiaohua |date=December 2017 |title=Air pollution, food production and food security: A review from the perspective of food system |journal=Journal of Integrative Agriculture |volume=16 |issue=12 |pages=2945–2962 |bibcode=2017JIAgr..16.2945S |doi=10.1016/S2095-3119(17)61814-8}}{{cite journal |last1=Lelieveld |first1=J. |last2=Evans |first2=J. S. |last3=Fnais |first3=M. |last4=Giannadaki |first4=D. |last5=Pozzer |first5=A. |date=September 2015 |title=The contribution of outdoor air pollution sources to premature mortality on a global scale |journal=Nature |language=en |volume=525 |issue=7569 |pages=367–371 |bibcode=2015Natur.525..367L |doi=10.1038/nature15371 |issn=1476-4687 |pmid=26381985 |hdl=20.500.14279/9356 |s2cid=4460927 |quote=Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity.}} For instance, methane is emitted by the digestion of food by cattle, causing ground-level ozone.{{cite web |date=5 February 2025 |title=Methane, climate change and air quality in Europe: exploring the connections |url=https://www.eea.europa.eu/en/analysis/publications/methane-climate-change-and-air-quality-in-europe-exploring-the-connections |access-date=7 March 2025 |publisher=European Environmental Agency}} Agriculture is also a major source of ammonia, which can form fine particulate matter.{{Cite journal |last1=Giannadaki |first1=Despina |last2=Giannakis |first2=Elias |last3=Pozzer |first3=Andrea |last4=Lelieveld |first4=Jos |date=2018-05-01 |title=Estimating health and economic benefits of reductions in air pollution from agriculture |url=https://www.sciencedirect.com/science/article/pii/S0048969717334836 |journal=Science of the Total Environment |volume=622-623 |pages=1304–1316 |doi=10.1016/j.scitotenv.2017.12.064 |pmid=29890597 |bibcode=2018ScTEn.622.1304G |issn=0048-9697}} Practices like slash-and-burn in forests like the Amazon cause large air pollution alongside deforestation.{{cite web |title=NASA's AIRS Maps Carbon Monoxide from Brazil Fires |url=https://www.jpl.nasa.gov/images/pia23356-nasas-airs-maps-carbon-monoxide-from-brazil-fires |website=NASA Jet Propulsion Laboratory (JPL) |access-date=4 August 2022}}

Open dumps of waste are a common source of air pollution in low-income countries. They can promote the growth of microbes which pollute water and air, and be a source of toxins. Through open burning of waste—whether self-ignited or burned on purpose—soot, methane, and other pollutants are released.{{Cite book |last=United Nations Environmental Programme |url=https://www.unep.org/resources/report/actions-air-quality-global-summary-policies-and-programmes-reduce-air-pollution |title=Actions on Air Quality: A Global Summary of Policies and Programmes to Reduce Air Pollution |date=2021 |isbn=978-92-807-3880-3 |pages=37–39}} The waste in landfills itself also produces methane.{{cite web |date=15 April 2016 |title=Basic Information about Landfill Gas |url=https://www.epa.gov/lmop/basic-information-about-landfill-gas |access-date=9 August 2022 |website=US Environmental Protection Agency |quote=Landfill gas (LFG) is a natural byproduct of the decomposition of organic material in landfills. LFG is composed of roughly 50 percent methane...}} Globally, a quarter of solid waste is not collected and another quarter is not disposed of properly.{{cite book |last1=Cook |first1=E |url=https://eprints.whiterose.ac.uk/169766/6/GRoSEEL_LR.pdf |title=Global Review on Safer End of Engineered Life |last2=Velis |publisher=Engineering X (founded by the Royal Academy of Engineering and the Lloyd's Register Foundation) |year=2020 |page=7}}

{{Main|Household air pollution|Indoor air quality|Energy poverty and cooking}}

File:Fish smoking in Ghana.jpg

As of 2023, more than 2.3 billion people in developing countries rely on burning polluting fuels such as firewood, agricultural waste, dry dung, coal or charcoal for cooking, which causes harmful household air pollution.{{Cite web |title=Executive summary – A Vision for Clean Cooking Access for All – Analysis |url=https://www.iea.org/reports/a-vision-for-clean-cooking-access-for-all/executive-summary |access-date=2025-01-09 |website=IEA |language=en-GB}} Kerosine, another polluting fuel, is used in many countries for lighting, and but sometimes also for space heating or cooking. Globally, 12% of PM_2.5 outdoor air pollution comes from household cooking. Health effects are concentrated among women, who are likely to be responsible for cooking, and young children.{{Cite book |url=https://www.who.int/publications/i/item/9789241565233 |title=Burning opportunity: clean household energy for health, sustainable development, and wellbeing of women and children |publisher=World Health Organization |year=2016 |location=Geneva, Switzerland |pages=vii–xi |archive-url=https://web.archive.org/web/20171124101534/http://www.who.int/airpollution/publications/burning-opportunities/en/ |archive-date=November 24, 2017 |url-status=live}}

Gas stoves for cooking contribute to indoor air pollution by emitting {{NOx|x=2}}, benzene and carbon monoxide.{{Cite news |last=Niranjan |first=Ajit |date=2024-10-28 |title=Pollutants from gas stoves kill 40,000 Europeans each year, report finds |url=https://www.theguardian.com/environment/2024/oct/28/pollutants-from-gas-stoves-kill-40000-europeans-each-year-report-finds |access-date=2025-03-21 |work=The Guardian |language=en-GB |issn=0261-3077}} Toasters can produce particulate pollution.{{Cite magazine |last=Twilley |first=Nicola |date=1 April 2019 |title=The Hidden Air Pollution in Our Homes |url=https://www.newyorker.com/magazine/2019/04/08/the-hidden-air-pollution-in-our-homes |archive-url=https://web.archive.org/web/20240727073125/https://www.newyorker.com/magazine/2019/04/08/the-hidden-air-pollution-in-our-homes |archive-date=27 July 2024 |magazine=The New Yorker |via=www.newyorker.com}} Similarly, heating systems such as furnaces and other types of fuel-burning heating devices release polllutants into the air.{{cite web |title=Combustion Pollutants in Your Home - Guidelines |url=https://ww2.arb.ca.gov/resources/documents/combustion-pollutants-your-home-guidelines |access-date=16 June 2022 |publisher=California Air Resources Board |quote="... most furnaces, wood stoves, fireplaces, gas water heaters, and gas clothes dryers, usually vent (exhaust) the combustion pollutants directly to the outdoors. However, if the vent system is not properly designed, installed, and maintained, indoor pollutants can build up quickly inside the home.}} In some developed countries, including the UK and Sydney, Australia, wood stoves are the major source of particulate pollution in urban areas.{{Cite web |title=Emissions of air pollutants in the UK – Particulate matter (PM10 and PM2.5) |url=https://www.gov.uk/government/statistics/emissions-of-air-pollutants/emissions-of-air-pollutants-in-the-uk-particulate-matter-pm10-and-pm25 |access-date=2025-01-27 |website=GOV.UK |language=en}}{{cite web |date=7 May 2024 |title=Wood burning heaters and your health |url=https://www.health.nsw.gov.au/environment/factsheets/Pages/wood-smoke.aspx |access-date=11 February 2025 |website=New South Wales Health |publisher=NSW Government}} Wood stoves can also emit carbon monoxide and {{NOx}}.

Other sources of indoor air pollution are radon, building materials, biological material and tobacco smoke. Biological material, such as dander, house dust mite, mold and pollen, can come from humans, animals or plants. Some of this material can trigger allergies, such as allergic rhinitis. Fumes from paint, hair spray, varnish, aerosol sprays can be substantial; emissions from these sources was estimated to account for almost half of pollution from volatile organic compounds in the Los Angeles basin in the 2010s.{{cite news |last1=Chatterjee |first1=Rhitu |date=15 February 2018 |title=Wall Paint, Perfumes and Cleaning Agents Are Polluting Our Air |url=https://www.npr.org/sections/thetwo-way/2018/02/15/585886321/your-wall-paint-perfumes-and-cleaning-agents-are-polluting-our-air |access-date=12 March 2019 |newspaper=NPR}}

File:Dust storm approaching Stratford, Texas.jpg, in 1935|alt=A dust storm approaches a collection of houses, dwarfing them in height.]]

Dust from desert can cause poor air quality far from its source. For instance, dust from the Gobi Desert in China and Mongolia can reach Hawaii, and dust from the Sahara reaches the Mediterennean.{{Cite web |date=10 May 2022 |title=What is desert dust and how does it change atmosphere and the air we breathe? |url=https://atmosphere.copernicus.eu/what-saharan-dust-and-how-does-it-change-atmosphere-and-air-we-breathe |access-date=2025-03-21 |website=Copernicus Atmosphere |language=en}}

Radon is a radioactive gas that can build up in buildings from the soil. It can cause lung cancer, especially in smokers. Levels are generally low, but can be elevated in buildings with "leaky" foundations or areas with soils rich in uranium.{{Cite book |title=Indoor air pollution |date=2019 |publisher=Royal Society of Chemistry |isbn=978-1-78801-617-9 |editor-last=Harrison |editor-first=Roy M. |series=Issues in environmental science and technology |location=London |pages=57–58 |editor-last2=Hester |editor-first2=Ronald E.}} Volcanic eruptions can be a large source of sulfur dioxide and also produces particle pollution.{{Citation |title=Emissions of Air Pollutants and Emission Control Technologies |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |pages=8–9 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/air-pollution/emissions-of-air-pollutants-and-emission-control-technologies/4CA3AB4F3F9D17F531345212A5677DDB |access-date=2025-06-04 |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.002 |isbn=978-1-108-48163-2}}

Vegetation, in some regions, emits environmentally significant amounts of volatile organic compounds (VOCs) on warmer days. These VOCs react with human pollution sources – specifically, NO_x, SO₂, and organic carbon – to produce a seasonal haze.{{cite journal|title=Biogenic carbon and anthropogenic pollutants combine to form a cooling haze over the southeastern United States |journal=Proceedings of the National Academy of Sciences |last1=Goldstein |first1=Allen H. |first2=Charles D. |last2=Koven |first3=Colette L. |last3=Heald |author3-link=Colette Heald |first4=Inez Y. |last4=Fung |date=5 May 2009 |doi=10.1073/pnas.0904128106 |pmid=19451635 |volume=106 |issue=22 |pages=8835–40 |pmc=2690056 |bibcode=2009PNAS..106.8835G |doi-access=free}} Black gum, poplar, oak and willow are some examples of vegetation that can produce abundant VOCs. The VOC production from these species result in ozone levels up to eight times higher than the low-impact tree species.{{cite journal|title=Trees That Pollute |first=Mark |last=Fischetti |journal=Scientific American |volume=310 |issue=6 |page=14 |doi=10.1038/scientificamerican0614-14 |pmid=25004561 |year=2014 |bibcode=2014SciAm.310f..14F}} Wildfires, which have become more severe and more common due to climate change, release fine particles. They are a major source of air pollution.{{Cite journal |last1=Knorr |first1=Wolfgang |last2=Dentener |first2=Frank |last3=Lamarque |first3=Jean-François |last4=Jiang |first4=Leiwen |last5=Arneth |first5=Almut |date=2017-07-31 |title=Wildfire air pollution hazard during the 21st century |url=https://acp.copernicus.org/articles/17/9223/2017/ |journal=Atmospheric Chemistry and Physics |language=English |volume=17 |issue=14 |pages=9223–9236 |doi=10.5194/acp-17-9223-2017 |doi-access=free |bibcode=2017ACP....17.9223K |issn=1680-7316}}

{{Main|Pollutant|Greenhouse gas emissions}}

File:Air Pollution-Causes&Effects.svg, (2) particulate pollution, (3) ozone-depleting gases, (4) acid rain, (5) ground-level ozone, (6) nitrogen oxides|alt=Schematic showing (1) CO2 and CH4 from heating, driving and livestock causing warming (2) PM pollution from driving (3) CFCs from buildings depleting ozone, causing UV to come through (4) SO2 from combustion causing acid rain and (5) ground-level ozone from nitrous oxides and (6) nitrous oxides from car exhausts.]]

Air pollutants can be tiny solid or liquid particles dispersed in the air (called aerosols), or gases.{{Cite book |last1=Pearson |first1=John K. |url=https://www.taylorfrancis.com/books/9781003293132 |title=Air Pollution and Climate Change: The Basics |last2=Derwent |first2=Richard G. |date=2022-04-19 |publisher=Routledge |isbn=978-1-003-29313-2 |edition=1 |location=London |pages=1, 6 |language=en |doi=10.4324/9781003293132}} Pollutants are classified as primary or secondary. Primary pollutants are produced directly by a source and remain in the same chemical form after they have been emitted into the atmosphere. Examples include carbon monoxide gas from car exhausts, and sulfur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react with each other or with other parts of the atmosphere. Ground-level ozone is one example of a secondary pollutant. Some pollutants may be both primary and secondary: they are both emitted directly and formed from other primary pollutants.{{cite book |last1=Harrison |first1=Roy M. |author1-link=Roy M. Harrison |url=https://iris.who.int/bitstream/handle/10665/107823/9789289021920-eng.pdf?sequence=1&isAllowed=y |title=Air Quality Guidelines: Global Update 2005: Particulate Matter, Ozone, Nitrogen Dioxide, and Sulfur Dioxide |date=2005 |publisher=World Health Organization |isbn=92-890-2192-6 |location=Copenhagen |pages=9–10, 13 |chapter=1: Sources of Air Pollution}}

Ammonia (NH₃) is emitted mainly by overuse of synthetic nitrogen fertilisers on farmland, and from manure and urine from livestock.{{Cite news|last=Carrington |first=Damian |date=2021-11-04 |title=Ammonia from farms behind 60% of UK particulate air pollution – study |url=https://www.theguardian.com/environment/2021/nov/04/ammonia-from-farms-behind-60-of-uk-particulate-air-pollution-study |access-date=2021-11-07 |work=The Guardian }} At typical concentrations in the air, it is not harmful to health directly. However, ammonia can react with other pollutants in the air to form ammonium sulfate or nitrate salts, contributing to particulate matter pollution. Furthermore, when ammonia is deposited onto the soil, it can harm ecosystems via eutrophication.{{Citation |title=Gaseous Pollutants |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |page=149 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/abs/air-pollution/gaseous-pollutants/66D443B7442EC23035C17FBF3EEDAAB2 |access-date= |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.008 |isbn=978-1-108-48163-2}}

Carbon dioxide ({{CO2}}) is mainly emitted by the burning of fossil fuels.{{Cite web |title=How much of U.S. carbon dioxide emissions are associated with electricity generation? |url=http://www.eia.gov/tools/faqs/faq.cfm?id=77&t=11 |access-date=16 December 2016}} It is potentially lethal at very high concentrations (typically 100 times "normal" atmospheric levels).{{cite web |title=Carbon dioxide |url=https://www.cdc.gov/niosh/npg/npgd0103.html |website=The National Institute for Occupational Safety and Health (NIOSH) |publisher=U.S. Department of Health & Human Services |access-date=19 April 2023 |date=30 October 2019}}{{cite web |title=General hazards of Carbon Dioxide |url=https://www.hse.gov.uk/carboncapture/carbondioxide.htm |website=Health and Safety Executive |publisher=UK Government |access-date=19 April 2023 |quote=For over a century {{CO2}} has been recognised as a workplace hazard at high concentrations. {{CO2}} is naturally present in the air we breathe at a concentration of about 0.037% and is not harmful to health at low concentrations.}} Although the World Health Organization recognizes {{CO2}} as a climate pollutant, it does not include the gas in its Air Quality Guidelines or set recommended targets for it.{{cite book |title=Air Quality Guidelines Global Update 2005: Particulate matter, ozone, nitrogen dioxide and sulfur dioxide |year=2006 |publisher=World Health Organization |location=Copenhagen, Denmark |isbn=92-890-2192-6 |page=12|quote="Some pollutants, and especially those associated with greenhouse warming effects (carbon dioxide, nitrous oxide and methane)..."}} Workplace exposure limits exist in places like UK (5,000 ppm for long-term exposure and 15,000 ppm for short-term exposure). Natural disasters like the limnic eruption at Lake Nyos can result in a large sudden release as well.{{cite web |title=The Strange Lake Nyos {{CO2}} Gas Disaster: Impacts and The Displacement and Return of Affected Communities |url=https://www.massey.ac.nz/~trauma/issues/2011-1/fomine.htm}}

{{CO2}} is sometimes called an air pollutant, because it is the main greenhouse gas responsible for climate change.{{cite web|last1=Vaidyanathan |first1=Gayathri |title=The Worst Climate Pollution Is Carbon Dioxide |url=https://www.scientificamerican.com/article/the-worst-climate-pollution-is-carbon-dioxide/ |publisher=Scientific American}}{{Cite book |last=Vallero |first=Daniel A. |title=Fundamentals of Air Pollution |date=2014 |publisher=Academic Press |isbn=978-0-12-401733-7|edition=5th|page=421}} This question of terminology has practical consequences, for example, in determining whether the U.S. Clean Air Act (which is designed to improve air quality) is deemed to regulate {{CO2}} emissions. The Inflation Reduction Act of 2022 amended the Clean Air Act to define {{CO2}} from fossil fuel burning explicitly as an air pollutant.{{cite news |last1=Friedman |first1=Lisa |title=Democrats Designed the Climate Law to Be a Game Changer. Here's How. |url=https://www.nytimes.com/2022/08/22/climate/epa-supreme-court-pollution.html |access-date=19 April 2023 |work=The New York Times |date=22 August 2022}}

Carbon monoxide (CO) is a colorless, odorless, toxic gas.{{Cite web|url=https://www.nhs.uk/conditions/carbon-monoxide-poisoning/|title=Carbon Monoxide Poisoning – NHS|date=17 October 2017}} It is a product of combustion of fuel such as natural gas, coal or wood. In the past, emissions from vehicles were the main source of CO, but modern vehicles do not emit much CO. Now, wildfires and bonfires are the main source of outdoors CO.{{Cite book |last1=Pearson |first1=John K. |title=Air pollution and climate change: the basics |last2=Derwent |first2=R. G. |date=2022 |publisher=Routledge, Taylor & Francis Group |isbn=978-1-003-29313-2 |edition=First |location=London ; New York, NY |page=2}} Indoors, CO is a larger problem and mainly comes from cooking and heating.{{Cite book |last1=Pearson |first1=John K. |title=Air pollution and climate change: the basics |last2=Derwent |first2=R. G. |date=2022 |publisher=Routledge, Taylor & Francis Group |isbn=978-1-003-29313-2 |edition=First |location=London ; New York, NY |pages=19–20}}

File:NASA - Human Fingerprint on Global Air Quality.webm or civil unrest.]]

Nitrogen oxides (NO_x), particularly nitrous oxide (NO), are mostly created by the burning of fossil fuels, and in lesser amounts by lightning. Nitrogen dioxide (NO₂) is formed from NO in a reaction with other atmospheric gases.{{Cite journal |last1=Pérez-Invernón |first1=Francisco J. |last2=Huntrieser |first2=Heidi |last3=Erbertseder |first3=Thilo |last4=Loyola |first4=Diego |last5=Valks |first5=Pieter |last6=Liu |first6=Song |last7=Allen |first7=Dale J. |last8=Pickering |first8=Kenneth E. |last9=Bucsela |first9=Eric J. |last10=Jöckel |first10=Patrick |last11=van Geffen |first11=Jos |last12=Eskes |first12=Henk |last13=Soler |first13=Sergio |last14=Gordillo-Vázquez |first14=Francisco J. |last15=Lapierre |first15=Jeff |date=2022-06-08 |title=Quantification of lightning-produced NOx over the Pyrenees and the Ebro Valley by using different TROPOMI-NO2 and cloud research products |url=https://amt.copernicus.org/articles/15/3329/2022/ |journal=Atmospheric Measurement Techniques |language=English |volume=15 |issue=11 |pages=3329–3351 |doi=10.5194/amt-15-3329-2022 |doi-access=free |issn=1867-1381}}{{Cite web |title=Emissions of air pollutants in the UK – Nitrogen oxides (NOx) |url=https://www.gov.uk/government/statistics/emissions-of-air-pollutants/emissions-of-air-pollutants-in-the-uk-nitrogen-oxides-nox |access-date=2025-03-15 |website=GOV.UK |language=en}} NO and NO₂ can form acid rain, can form into a haze, and can cause nutrient pollution in water.{{Cite web |last=US EPA |date=16 July 2024 |title=Basic Information about NO₂ |url=https://www.epa.gov/no2-pollution/basic-information-about-no2 |access-date=2025-03-15 |website=www.epa.gov |language=en}} NO₂ is a reddish-brown toxic gas with a strong odor, whereas NO is odorless and does not have a color.{{Cite web |title=Nitrogen oxides, NOx |url=https://www.eea.europa.eu/help/glossary/eper-chemicals-glossary/nitrogen-oxides-nox |access-date=2025-03-15 |website=European Environment Agency |language=en}}

Particulate matter (PM), also known as particle pollution, includes all airborne substances that are not gases.{{Cite web |last=US EPA |date=2016-04-19 |title=Particulate Matter (PM) Basics |url=https://www.epa.gov/pm-pollution/particulate-matter-pm-basics |access-date=2025-04-19 |website=www.epa.gov |language=en}} It is a mix of microscopic solid particles or droplets suspended in a gas.{{Cite web |date=March 29, 2022 |title=What is Particulate Matter? {{!}} Urban Environmental Program in New England |url=https://www3.epa.gov/region1/eco/uep/particulatematter.html |url-status=deviated |archive-url=https://web.archive.org/web/20220607141238/https://www3.epa.gov/region1/eco/uep/particulatematter.html |archive-date=2022-06-07 |access-date=2022-06-07 |website=US EPA |language=en}} They consist of a large variety of materials and chemical compounds including toxic substances, and they vary strongly in size. Coarse PM (PM₁₀) is 10 micrometer (μm) or smaller, fine PM (PM_2.5) is smaller than 2.5 μm, and ultrafine particles are 0.1 μm or smaller.{{Cite journal |last1=Garcia-Marlès |first1=Meritxell |last2=Lara |first2=Rosa |last3=Reche |first3=Cristina |last4=Pérez |first4=Noemí |last5=Tobías |first5=Aurelio |last6=Savadkoohi |first6=Marjan |last7=Beddows |first7=David |last8=Salma |first8=Imre |last9=Vörösmarty |first9=Máté |last10=Weidinger |first10=Tamás |last11=Hueglin |first11=Christoph |last12=Mihalopoulos |first12=Nikos |last13=Grivas |first13=Georgios |last14=Kalkavouras |first14=Panayiotis |last15=Ondráček |first15=Jakub |date=2024-03-01 |title=Inter-annual trends of ultrafine particles in urban Europe |url=https://linkinghub.elsevier.com/retrieve/pii/S0160412024000965 |journal=Environment International |volume=185 |pages=108510 |doi=10.1016/j.envint.2024.108510 |pmid=38460241 |bibcode=2024EnInt.18508510G |issn=0160-4120}} Smaller articles pose more risk to health, as they can reach the bloodstream.

Sea spray, wildfires, volcanoes and dust storms are the main natural sources of PM, while the burning of biomass and fossil fuels, as well as road emissions and dust resuspension are the main human sources. Human PM is usually finer than natural PM.{{Cite journal |last1=Mukherjee |first1=Arideep |last2=Agrawal |first2=Madhoolika |date=2017-06-01 |title=World air particulate matter: sources, distribution and health effects |url=https://link.springer.com/article/10.1007/s10311-017-0611-9 |journal=Environmental Chemistry Letters |language=en |volume=15 |issue=2 |pages=283–309 |doi=10.1007/s10311-017-0611-9 |bibcode=2017EnvCL..15..283M |issn=1610-3661}} A definitive link between fine particulate pollution and higher death rates in urban areas was established by the Harvard Six Cities study, published in 1993.{{cite journal |last1=Laden |first1=F |title=A Tale of Six Cities: The Landmark Harvard Six Cities Study |journal=Environmental Epidemiology |date=October 2019 |volume=3 |page=221 |doi=10.1097/01.EE9.0000608272.94008.7b |s2cid=210638367 |doi-access=free |bibcode=2019EnEpi...3Q.221L }}

Sulfur dioxide (SO₂), an acidic and corrosive gas, is produced mostly by the burning of crude oil and coal. These fossil fuels often contain sulfur compounds, and their combustion generates sulfur dioxide.{{Cite web |title=Emissions of air pollutants in the UK – Sulphur dioxide (SO2) |url=https://www.gov.uk/government/statistics/emissions-of-air-pollutants/emissions-of-air-pollutants-in-the-uk-sulphur-dioxide-so2 |access-date=2025-04-21 |website=GOV.UK |language=en}} In Europe and North America, SO₂ is mostly found in areas with significant shipping and industry, as road traffic fuels are regulated.{{Citation |title=Gaseous Pollutants |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |page=146 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/abs/air-pollution/gaseous-pollutants/66D443B7442EC23035C17FBF3EEDAAB2 |access-date= |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.008 |isbn=978-1-108-48163-2}} Smaller amounts of SO₂ are released from smelting and volcanoes.

High concentrations of SO₂ in the air generally also lead to the formation of other sulfur oxides (SO_x). SO_x can react with other compounds in the atmosphere to form small particles and contribute to particulate matter pollution. At high concentrations, gaseous SO_x can harm plants by damaging leafs and decreasing growth.{{cite web |date=2 Jun 2016 |title=Sulfur Dioxide Basics |url=https://www.epa.gov/so2-pollution/sulfur-dioxide-basics |url-status=live |archive-url=https://web.archive.org/web/20250101120025/https://www.epa.gov/so2-pollution/sulfur-dioxide-basics |archive-date=2025-01-01 |access-date=12 Jan 2025 |website=US EPA}} {{PD-notice}} Further oxidation of SO₂, mostly taking place in cloud droplets, forms sulfuric acid (H₂SO₄), which is one of the components of acid rain.{{Cite book |last=Seigneur |first=Christian |title=Air pollution: concepts, theory, and applications |date=2019 |publisher=Cambridge University Press |isbn=978-1-108-48163-2 |location=Cambridge, United Kingdom ; New York, NY |pages=249–250, 254}}

File:SMOG-DAMAGED PLANT AT THE STATEWIDE AIR POLLUTION RESEARCH CENTER, UNIVERSITY OF CALIFORNIA. PLANT - NARA - 542686.jpg

Ground-level ozone (O₃) is mostly created when NO_x and volatile organic compounds mix in the presence of sunlight. It can also be formed from carbon monoxide or methane.{{Cite web |date=2025-03-17 |title=Ground-level ozone |url=https://climate-adapt.eea.europa.eu/en/observatory/evidence/health-effects/ground-level-ozone#:~:text=Ground-level%20ozone%20affects%20human,use,%20and%20even%20premature%20mortality. |access-date=2025-04-21 |publisher=European Climate and Health Observatory |language=en}} Due to the influence of temperature and sunlight on this reaction, high ozone levels are most common on hot summer afternoons.{{Cite web |last=Arkansas Energy Department of Energy and Environment |title=Cars and Air Pollution |url=https://www.adeq.state.ar.us/air/planning/ozone/cars.aspx |access-date=2024-08-24 |website=www.adeq.state.ar.us}} It can be harmful to human health, but also to some materials, forests, wild plants and crops. It can react with other compounds in the air to form photochemical smog.{{Cite web |title=Ozone (O3) |url=https://www.gov.uk/government/statistics/air-quality-statistics/concentrations-of-ozone |access-date=2025-04-21 |website=GOV.UK |language=en}} Smog is a particular problem in big cities where it cannot be easily be transported away by wind, for instance cities built in valleys surrounded by mountains.{{Cite web |title=smog {{!}} National Geographic Society |url=https://education.nationalgeographic.org/resource/smog/ |access-date=2022-06-07 |website=education.nationalgeographic.org |publisher=National Geographic}} When ground-level ozone is produced, it can linger in the air for days or weeks, and therefore be transported far from where it was first formed.

Volatile organic compounds (VOC) are air pollutants found both indoors and outdoors.{{cite web |date=24 February 2025 |title=Technical Overview of Volatile Organic Compounds |url=https://www.epa.gov/indoor-air-quality-iaq/technical-overview-volatile-organic-compounds |access-date=1 April 2025 |website=US Environmental Protection Agency}} VOCs are a large group of compounds which can cause photochemical smog and form aerosols impacting climate. The group includes methane, CO, acetone and toluene. Some can cause cancer, such as butadiene and benzene,{{Cite journal |last=Lewis |first=Alastair C. |date=2018-02-16 |title=The changing face of urban air pollution |url=https://www.science.org/doi/10.1126/science.aar4925 |journal=Science |language=en |volume=359 |issue=6377 |pages=744–745 |doi=10.1126/science.aar4925 |pmid=29449479 |bibcode=2018Sci...359..744L |issn=0036-8075}} with benzene being released from cigarette smoking. Methane is a greenhouse gas and the second-largest driver global warming. Other VOCs contribute to climate warming because they help form ground-level ozone, a greenhouse gas.{{Cite book |last1=Pearson |first1=John K. |url=https://www.taylorfrancis.com/books/9781003293132 |title=Air Pollution and Climate Change: The Basics |last2=Derwent |first2=Richard G. |date=2022-04-19 |publisher=Routledge |isbn=978-1-003-29313-2 |edition=1 |location=London |pages=4–5 |language=en |doi=10.4324/9781003293132}}

Some heavy metals can have negative effects on health. For instance, lead exposure can lead to learning disabilities in children. In the atmosphere, they can be exist in different states, such as particles or gases. One of the forms of chromium can cause cancer. Mercury is harmful both in its elemental form and when it is in an organic compound. In the atmosphere, it comes mostly from cement production, burning of coal and incinerators.{{Citation |title=Environmental Impacts |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |pages=311–316 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/abs/air-pollution/environmental-impacts/8F47851775A4681857CEB599B3C32DF5 |access-date= |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.013 |isbn=978-1-108-48163-2}}

Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation. As a result, they persist in the environment, are capable of long-range transmission, bioaccumulate in humans and animals and biomagnify in food chains.{{cite book |last1=Singh |first1=Ritu |url=https://books.google.com/books?id=NiRAEAAAQBAJ |title=Persistent Organic Pollutants in the Environment: Origin and Role |last2=Kumar |first2=Sanjeev |last3=Karmakar |first3=Susmita |last4=Siddiqui |first4=Arif J. |last5=Mathur |first5=Ankita |last6=Adnan |first6=Mohd. |last7=Rajput |first7=Vishnu D. |last8=Rani |first8=Anita |last9=Kumar |first9=Narendra |date=2021 |publisher=CRC Press |isbn=978-1-003-05317-0 |editor1-last=Kumar |editor1-first=Narendra |pages=31–54 |chapter=2: Causes, Consequences, and Control of Persistent Organic Pollutants |access-date=11 June 2022 |editor2-last=Shukla |editor2-first=Vertika}} The Stockholm Convention on Persistent Organic Pollutants identified pesticides and other POPs of concern. These include dioxins and furans which are created by waste combustion. POPs are usually either semi-volatile (gaseous only at higher temperatures) or non-volatile (emitted as particles). The harmful effects of the pesticide DDT, a POP, was popularised Silent Spring in the 1960.{{Citation |title=Environmental Impacts |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |pages=309–311 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/abs/air-pollution/environmental-impacts/8F47851775A4681857CEB599B3C32DF5 |access-date= |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.013 |isbn=978-1-108-48163-2}} PFASs and polycyclic aromatic hydrocarbons (PAHs) are other examples of POPs.{{Cite journal |last1=Negrete-Bolagay |first1=Daniela |last2=Zamora-Ledezma |first2=Camilo |last3=Chuya-Sumba |first3=Cristina |last4=De Sousa |first4=Frederico B. |last5=Whitehead |first5=Daniel |last6=Alexis |first6=Frank |last7=Guerrero |first7=Victor H. |date=2021-12-15 |title=Persistent organic pollutants: The trade-off between potential risks and sustainable remediation methods |url=https://linkinghub.elsevier.com/retrieve/pii/S0301479721017990 |journal=Journal of Environmental Management |volume=300 |pages=113737 |doi=10.1016/j.jenvman.2021.113737 |pmid=34536739 |bibcode=2021JEnvM.30013737N |issn=0301-4797}}

Chlorofluorocarbons (CFCs) are a group of compounds which harm the ozone layer. These gases were emitted by air conditioners, freezers, aerosol sprays, and other similar devices. CFCs reach the stratosphere after being released into the atmosphere.{{Cite web |last=US EPA |first=OAR |date=2017-06-05 |title=Basic Ozone Layer Science |url=https://www.epa.gov/ozone-layer-protection/basic-ozone-layer-science |access-date=2022-06-07 |website=www.epa.gov |publisher=US Environmental Protection Agency }} They interact with other gases here, causing harm to the ozone layer. UV rays are able to reach the Earth's surface as a result of this. This can result in skin cancer, eye problems, and even plant damage.{{Cite web |title=Chlorofluorocarbons (CFCs) are heavier than air, so how do scientists suppose that these chemicals reach the altitude of the ozone layer to adversely affect it? |url=https://www.scientificamerican.com/article/chlorofluorocarbons-cfcs/ |access-date=2022-06-07 |website=Scientific American }}

File:Air Quality (PM 2.5) Regional Overview.svgExposure to air pollution varies widely across the world and across groups.{{Cite journal |last1=Hajat |first1=Anjum |last2=Hsia |first2=Charlene |last3=O'Neill |first3=Marie S. |date=2015 |title=Socioeconomic Disparities and Air Pollution Exposure: a Global Review |journal=Current Environmental Health Reports |language=en |volume=2 |issue=4 |pages=440–450 |doi=10.1007/s40572-015-0069-5 |issn=2196-5412 |pmc=4626327 |pmid=26381684|bibcode=2015CEHR....2..440H }} For instance, children are more exposed to air pollution as they breathe at a higher rate than adults. Because they are shorter, they breathe in air closer to the ground, which usually has higher pollution levels (for instance, from vehicle exhaust or dust). Somebody doing strenuous exercise will breathe in more pollution than somebody who is sitting typically.{{Cite book |last=Vallero |first=Daniel A. |url=https://shop.elsevier.com/books/fundamentals-of-air-pollution/vallero/978-0-12-373615-4 |title=Fundamentals of Air Pollution |date=1 October 2007 |publisher=Academic Press |isbn=978-0-12-405481-3 |edition=4th}}

File:Share-above-who-pollution-guidelines (OWID 0948).pngFor some pollutants, low exposure can be seen as safe, whereas other pollutants have negative health effects even at low levels.{{cite web |title=Air quality, energy and health |url=https://www.who.int/teams/environment-climate-change-and-health/air-quality-energy-and-health/health-impacts |access-date=16 January 2025 |website=World Health Organization}} As evidence has grown that even very low levels of air pollutants hurt human health, the WHO halved its recommended safe limit for particulate matter from 10 μg/m³ to 5 μg/m³ in 2021. Under the new guideline, nearly the entire global population—97.3 percent—is classified as exposed to unsafe levels of PM_2.5.{{Cite web |date=2022-06-14 |title=Most of the World Breathes Unsafe Air, Taking More Than 2 Years Off Global Life Expectancy |url=https://aqli.epic.uchicago.edu/news/most-of-the-world-breathes-unsafe-air-taking-more-than-2-years-off-global-life-expectancy/ |access-date=2022-07-12 |website=AQLI}} The new limit for nitrogen dioxide (NO₂) became 75% lower.{{Cite web |last=Carrington |first=Damian |date=2021-09-22 |title=WHO slashes guideline limits on air pollution from fossil fuels |url=https://www.theguardian.com/environment/2021/sep/22/who-cuts-guideline-limits-on-air-pollution-from-fossil-fuels |access-date=2021-09-22 |website=The Guardian}} For all pollutants together, the WHO concluded that 99% of the world population is exposed to harmful air pollution.{{Cite web |title=Billions of people still breathe unhealthy air: new WHO data |url=https://www.who.int/news/item/04-04-2022-billions-of-people-still-breathe-unhealthy-air-new-who-data |access-date=2025-01-14 |website=World Health Organization |language=en}}

For some pollutants such as black carbon, traffic related exposures may dominate total exposure despite short exposure times since high concentrations coincide with proximity to major roads or participation in (motorized) traffic.{{cite journal|last=Dons |first=E. |title=Impact of time-activity patterns on personal exposure to black carbon |journal=Atmospheric Environment |volume=45 |issue=21 |pages=3594–3602 |year=2011 |doi=10.1016/j.atmosenv.2011.03.064 |bibcode=2011AtmEn..45.3594D}} A large portion of total daily exposure occurs as short peaks of high concentrations.{{cite journal |last=Dons |first=E. |title=Transport most likely to cause air pollution peak exposures in everyday life: Evidence from over 2000 days of personal monitoring |journal=Atmospheric Environment |volume=213 |pages=424–432 |year=2019 |doi=10.1016/j.atmosenv.2019.06.035 |bibcode=2019AtmEn.213..424D |hdl=10044/1/80194 |s2cid=197131423 |hdl-access=free}}

{{Main|Toxic hotspot|Environmental justice}}

While air pollution affects a variety of populations, some groups are more exposed. In many regions, there are disparities in exposure to pollution by race and income. This is especially true in countries with high inequalities in incomes and healthcare, like the United States. Polluting industries and roads are more likely to be placed in poorer communities, and people in these communities are more likely to work outdoors, leading to additional exposure.{{Cite journal |last1=Rentschler |first1=Jun |last2=Leonova |first2=Nadezda |date=2023-07-22 |title=Global air pollution exposure and poverty |journal=Nature Communications |language=en |volume=14 |issue=1 |page=4432 |doi=10.1038/s41467-023-39797-4 |issn=2041-1723 |pmc=10363163 |pmid=37481598|bibcode=2023NatCo..14.4432R }} Residents in public housing, who are generally low-income and cannot easily move to healthier neighborhoods, are highly affected by nearby refineries and chemical plants.{{cite journal |last=Lerner |first=Steve |year=2010 |title=Sacrifice Zones: The Front Lines of Toxic Chemical Exposure in the United States |journal=Port Arthur, Texas: Public Housing Residents Breathe Contaminated Air from Nearby Refineries and Chemical Plants |publisher=MIT Press}}

Additionally, lower-income communities more often perform polluting activities, such as using solid biofuels for cooking.{{Cite journal |last1=Reddington |first1=C. L. |last2=Turnock |first2=S. T. |last3=Conibear |first3=L. |last4=Forster |first4=P. M. |last5=Lowe |first5=J. A. |last6=Ford |first6=L. Berrang |last7=Weaver |first7=C. |last8=van Bavel |first8=B. |last9=Dong |first9=H. |last10=Alizadeh |first10=M. R. |last11=Arnold |first11=S. R. |date=2023 |title=Inequalities in Air Pollution Exposure and Attributable Mortality in a Low Carbon Future |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023EF003697 |journal=Earth's Future |language=en |volume=11 |issue=12 |doi=10.1029/2023EF003697 |bibcode=2023EaFut..1103697R |issn=2328-4277}}{{Cite journal |last1=Rao |first1=Narasimha D. |last2=Kiesewetter |first2=Gregor |last3=Min |first3=Jihoon |last4=Pachauri |first4=Shonali |last5=Wagner |first5=Fabian |date=2021-07-26 |title=Household contributions to and impacts from air pollution in India |url=https://www.nature.com/articles/s41893-021-00744-0 |journal=Nature Sustainability |language=en |volume=4 |issue=10 |pages=859–867 |doi=10.1038/s41893-021-00744-0 |bibcode=2021NatSu...4..859R |issn=2398-9629}} Communities with a low socioeconomic status and minority groups also have a higher risk of diseases for the same level of pollution than more privileged communities.{{cite journal |last1=Morello-Frosch |first1=Rachel |last2=Zuk |first2=Miriam |last3=Jerrett |first3=Michael |last4=Shamasunder |first4=Bhavna |last5=Kyle |first5=Amy D. |year=2011 |title=Understanding the Cumulative Impacts of Inequalities in Environmental Health: Implications for Policy |journal=Health Affairs |volume=30 |issue=5 |pages=879–87 |doi=10.1377/hlthaff.2011.0153 |pmid=21555471 |doi-access=free}} In the United States, Blacks and Latinos generally face more pollution than Whites and Asians.{{cite journal |last1=Drury |first1=Richard |last2=Belliveau |first2=Michael |last3=Kuhn |first3=J. Scott |last4=Shipra |first4=Bansal |date=Spring 1999 |title=Pollution Trading and Environmental Justice: Los Angeles' Failed Experiment in Air Pollution Policy |journal=Duke Environmental Law & Policy Forum |volume=9 |issue=231}}

{{further information|List of most polluted cities in the world by particulate matter concentration|List of least polluted cities by particulate matter concentration}}

Exposure to outdoor air pollution is worst in lower-middle income countries in line with the environmental Kuznets curve, which postulates that pollution is worst in economies that rely on manufacturing but have not yet been able to prioritize environmental regulation.{{cite journal |last1=Rentschler |first1=Jun |last2=Leonova |first2=Nadezda |date=2023 |title=Global air pollution exposure and poverty |journal=Nature Communications |volume=14 |issue=1 |page=4432 |bibcode=2023NatCo..14.4432R |doi=10.1038/s41467-023-39797-4 |pmc=10363163 |pmid=37481598 |doi-access=free}} Indoor air pollution is worst in low-income countries, in particularly south-east Asia, the western Pacific and Africa.{{Cite book |url=https://www.who.int/publications/i/item/9789241565233 |title=Burning opportunity: clean household energy for health, sustainable development, and wellbeing of women and children |publisher=World Health Organization |year=2016 |location=Geneva, Switzerland |page=17-18 |archive-url=https://web.archive.org/web/20171124101534/http://www.who.int/airpollution/publications/burning-opportunities/en/ |archive-date=November 24, 2017 |url-status=live}}

Outdoor air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where cities are experiencing rapid growth and environmental regulations are relatively lax or nonexistent. Urbanization leads to a rapid rise in premature mortality due to air pollution in fast-growing tropical cities.{{Cite journal |last1=Vohra |first1=Karn |last2=Marais |first2=Eloise A. |last3=Bloss |first3=William J. |last4=Schwartz |first4=Joel |last5=Mickley |first5=Loretta J. |last6=Van Damme |first6=Martin |last7=Clarisse |first7=Lieven |last8=Coheur |first8=Pierre-F. |date=2022-04-08 |title=Rapid rise in premature mortality due to anthropogenic air pollution in fast-growing tropical cities from 2005 to 2018 |journal=Science Advances |language=en |volume=8 |issue=14 |pages=eabm4435 |doi=10.1126/sciadv.abm4435 |pmid=35394832 |pmc=8993110 |bibcode=2022SciA....8M4435V |issn=2375-2548}} Indoor air pollution on the other hand is most common in rural areas, which may lack access to clean cooking fuels.

File:Share of deaths from indoor air pollution, OWID.svg

Air pollution is an important risk factor for various diseases, such as COPD (a common lung disease), stroke, heart disease, lung cancer and pneumonia. Indoor air pollution is also associated with cataract.{{cite web|url=https://www.who.int/teams/environment-climate-change-and-health/air-quality-energy-and-health/health-impacts|publisher=World Health Organization|title=Air quality, energy and health|access-date=13 February 2025}} Air pollution has further been linked to brain disorders, such as dementia, depression, anxiety and psychosis.{{Cite journal |last=Drew |first=Liam |date=2025-01-14 |title=Air pollution and brain damage: what the science says |url=https://www.nature.com/articles/d41586-025-00053-y |journal=Nature |language=en |volume=637 |issue=8046 |pages=536–538 |doi=10.1038/d41586-025-00053-y |pmid=39809913 |bibcode=2025Natur.637..536D |issn=1476-4687}} Diseases that develop from persistent exposure to air pollution are environmental health diseases, which develop when a health environment is not maintained.{{cite book |last1=Dovjak |first1=Mateja |title=Creating Healthy and Sustainable Buildings |last2=Kukec |first2=Andreja |publisher=Springer International Publishing |year=2019 |isbn=978-3-030-19411-6 |publication-place=Switzerland |pages=43–82 |chapter=Health Outcomes Related to Built Environments |doi=10.1007/978-3-030-19412-3_2 |oclc=1285508857 |s2cid=190160283}}

Pollutants strongly linked to negative health effects include particulate matter,{{Cite journal |last=Thompson |first=Jonathan E. |date=May 2018 |title=Airborne Particulate Matter: Human Exposure and Health Effects |url=https://journals.lww.com/joem/abstract/2018/05000/airborne_particulate_matter__human_exposure_and.2.aspx |journal=Journal of Occupational and Environmental Medicine |language=en-US |volume=60 |issue=5 |pages=392–423 |doi=10.1097/JOM.0000000000001277 |pmid=29334526 |issn=1076-2752}} carbon monoxide,{{Cite journal |last1=Chen |first1=Tze-Ming |last2=Kuschner |first2=Ware G. |last3=Gokhale |first3=Janaki |last4=Shofer |first4=Scott |date=2007-04-01 |title=Outdoor Air Pollution: Nitrogen Dioxide, Sulfur Dioxide, and Carbon Monoxide Health Effects |url=https://www.sciencedirect.com/science/article/abs/pii/S0002962915325933 |journal=The American Journal of the Medical Sciences |volume=333 |issue=4 |pages=249–256 |doi=10.1097/MAJ.0b013e31803b900f |pmid=17435420 |issn=0002-9629}} nitrogen dioxide (NO₂), ozone (O₃),{{Cite web |last=American Lung Association |title=Ozone |url=https://www.lung.org/clean-air/outdoors/what-makes-air-unhealthy/ozone |access-date=2025-05-02 |website=www.lung.org |language=en}} and sulphur dioxide (SO₂). Fine particulates are especially damaging, as they can enter the bloodstream via the lungs and reach other organs.{{Cite web |last=US EPA |first=OAR |date=2016-04-26 |title=Health and Environmental Effects of Particulate Matter (PM) |url=https://www.epa.gov/pm-pollution/health-and-environmental-effects-particulate-matter-pm |access-date=2025-05-02 |website=www.epa.gov |language=en}}{{Cite journal |last=Schraufnagel |first=Dean E. |date=2020 |title=The health effects of ultrafine particles |journal=Experimental & Molecular Medicine |volume=52 |issue=3 |pages=311–317 |doi=10.1038/s12276-020-0403-3 |issn=2092-6413 |pmc=7156741 |pmid=32203102}} Air pollution causes disease by driving inflammation and oxidative stress, suppressing the immune system and by damaging DNA.

Even at very low levels (under the World Health Organization recommended levels), fine particulates can continue to cause harm.{{Cite book |last1=Health Effects Institute |author-link1=Health Effects Institute |url=https://www.stateofglobalair.org/resources/report/state-global-air-report-2024 |title=State of Global Air Report 2024: A Special Report on Global Exposure to Air Pollution and its Health Impacts with a Focus on Children's Health. |last2=Institute for Health Metrics and Evaluation |author-link2=Institute for Health Metrics and Evaluation |last3=UNICEF |author-link3=UNICEF |date=2024 |publisher=Health Effects Institute |pages=7–8 |issn=2578-6873}} However, according to the WHO, 99% of the world's population lives in areas with air pollution that exceeds WHO recommended levels.{{Cite web |last=World Health Organization |title=Air pollution |url=https://www.who.int/health-topics/air-pollution#tab=tab_1 |access-date=2025-05-02 |website=www.who.int |language=en}} People living in poverty, babies and older people are also disproportionately affected by air pollution; pregnancy is also more risky when exposed to air pollution.{{Cite book |last1=Health Effects Institute |author-link1=Health Effects Institute |url=https://www.stateofglobalair.org/resources/report/state-global-air-report-2024 |title=State of Global Air Report 2024: A Special Report on Global Exposure to Air Pollution and its Health Impacts with a Focus on Children's Health. |last2=Institute for Health Metrics and Evaluation |author-link2=Institute for Health Metrics and Evaluation |last3=UNICEF |author-link3=UNICEF |date=2024 |publisher=Health Effects Institute |page=4 |issn=2578-6873}}

File:How-many-people-die-from-air-pollution-1-1.png

File:Death-rate-from-air-pollution-map 2021 IHME.svg)|alt=map showing low death rates in Europe and the Americas, and high death rates in South and South East Asia, and Africa|upright=1.4]]Estimates of deaths due to air pollution vary.{{Cite journal |last=Roser |first=Max |date=2024-03-18 |title=Data review: how many people die from air pollution? |url=https://ourworldindata.org/data-review-air-pollution-deaths |journal=Our World in Data}} The 2024 Global Burden of Disease Study estimates that air pollution contributed to 8.1 million deaths in 2021, which is more than 1 in 8 deaths. Outdoor particulate pollution (PM2.5) was the largest cause of death (4.7 million), followed by indoor air pollution (3.1 million) and ozone (0.5 million).

The WHO estimates that 6.7 million people die from air pollution each year, 4.2 million due to outdoor air pollution.{{cite news |title=Ambient (outdoor) air pollution|date=24 October 2024 |url=https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health |access-date=15 January 2025 |work=www.who.int |publisher=World Health Organization}} Roughly 68% of outdoor air pollution-related premature deaths were due to ischaemic heart disease and stroke, 14% due to COPD and 14% due to lung infections (lower respiratory tract infections).

A study published in 2019 estimated that, for 2015, the number was around 8.8 million, with 5.5 million of these premature deaths due to air pollution from human sources.{{Cite journal |last1=Lelieveld |first1=J. |last2=Klingmüller |first2=K. |last3=Pozzer |first3=A. |last4=Burnett |first4=R. T. |last5=Haines |first5=A. |last6=Ramanathan |first6=V. |date=2019-04-09 |title=Effects of fossil fuel and total anthropogenic emission removal on public health and climate |journal=Proceedings of the National Academy of Sciences |language=en |volume=116 |issue=15 |pages=7192–7197 |bibcode=2019PNAS..116.7192L |doi=10.1073/pnas.1819989116 |issn=0027-8424 |pmc=6462052 |pmid=30910976 |doi-access=free}} The global mean loss of life expectancy from air pollution in 2015 was 2.9 years, substantially more than, for example, 0.3 years from all forms of direct violence.{{cite journal |last1=Lelieveld |first1=Jos |last2=Pozzer |first2=Andrea |last3=Pöschl |first3=Ulrich |last4=Fnais |first4=Mohammed |last5=Haines |first5=Andy |last6=Münzel |first6=Thomas |title=Loss of life expectancy from air pollution compared to other risk factors: a worldwide perspective |journal=Cardiovascular Research |date=1 September 2020 |volume=116 |issue=11 |pages=1910–1917 |doi=10.1093/cvr/cvaa025 |pmid=32123898 |pmc=7449554 |issn=0008-6363}}

India and China have the higher number of deaths from air pollution. In India, it contributed to 2.1 million deaths in 2021, whereas China saw 2.4 million deaths.{{Cite web |date=20 May 2024 |title=Deaths from air pollution |url=https://ourworldindata.org/grapher/air-pollution-deaths-country |archive-url=https://web.archive.org/web/20250114131817/https://ourworldindata.org/grapher/air-pollution-deaths-country |archive-date=14 January 2025 |access-date=2025-01-19 |website=Our World in Data |language=en |url-status=live }} In some countries, more than 20% of deaths were attributed to air pollution, for instance in Nepal, Bangladesh, Laos and North Korea. Air pollution deaths are high in middle-income countries due to industry and in low-income countries due to the use of solid fuels for cooking.{{Cite journal |last1=Ritchie |first1=Hannah |last2=Roser |first2=Max |date=February 2024 |title=Air Pollution |url=https://ourworldindata.org/air-pollution |journal=Our World in Data |language=en |access-date=19 January 2024}}

Annual premature European deaths from air pollution are estimated at 416,000{{Cite web |date=2024-12-10 |title=Harm to human health from air pollution in Europe: burden of disease status, 2024 |url=https://www.eea.europa.eu/en/analysis/publications/harm-to-human-health-from-air-pollution-2024 |access-date=2025-02-15 |website=www.eea.europa.eu |language=en}} to 800,000.{{cite news|last=Carrington |first=Damian |date=12 March 2019 |title=Air pollution deaths are double previous estimates, finds research |url=https://www.theguardian.com/environment/2019/mar/12/air-pollution-deaths-are-double-previous-estimates-finds-research |access-date=12 March 2019 |work=The Guardian}} The UK saw some 17,000 deaths in 2021 due to air pollution. Nigeria, Indonesia and Pakistan each saw over 200,000 deaths resulting from air pollution.{{Cite web |title=Explore the Data {{!}} State of Global Air |url=https://www.stateofglobalair.org/data |access-date=2025-02-15 |website=www.stateofglobalair.org}}

Eliminating energy-related emissions in the United States would prevent 46,900–59,400 premature deaths each year and provide $537–$678 billion in benefits from avoided PM_2.5-related illness and death.{{cite journal |last1=Mailloux |first1=Nicholas A. |last2=Abel |first2=David W. |last3=Holloway |first3=Tracey |last4=Patz |first4=Jonathan A. |date=16 May 2022 |title=Nationwide and Regional PM2.5-Related Air Quality Health Benefits From the Removal of Energy-Related Emissions in the United States |journal=GeoHealth |volume=6 |issue=5 |pages=e2022GH000603 |bibcode=2022GHeal...6..603M |doi=10.1029/2022GH000603 |pmc=9109601 |pmid=35599962}} A 2023 study on sulfur dioxide emissions by coal power plants (coal PM_2.5) concluded that "exposure to coal PM_2.5 was associated with 2.1 times greater mortality risk than exposure to PM_2.5 from all sources."{{cite journal |last1=Henneman |first1=Lucas |last2=Choirat |first2=Christine |last3=Dedoussi |first3=Irene |last4=Dominici |first4=Francesca |last5=Roberts |first5=Jessica |last6=Zigler |first6=Corwin |date=24 November 2023 |title=Mortality risk from United States coal electricity generation |journal=Science |volume=382 |issue=6673 |pages=941–946 |bibcode=2023Sci...382..941H |doi=10.1126/science.adf4915 |pmc=10870829 |pmid=37995235}} From 1999 to 2020, a total of 460,000 deaths in the US were attributed to coal PM_2.5.

{{Further|#Sources}}

{{multiple image

| total_width = 300

| image1 = 2021 Death rates, by energy source.svg

| caption1 = Deaths caused by accidents and air pollution from fossil fuel use in power plants exceed those caused by production of renewable energy.{{cite journal |last1=Ritchie |first1=Hannah |author1-link=Hannah Ritchie |last2=Roser |first2=Max |author2-link=Max Roser |title=What are the safest and cleanest sources of energy? |url=https://ourworldindata.org/safest-sources-of-energy |journal=Our World in Data |archive-url=https://web.archive.org/web/20240115112316/https://ourworldindata.org/safest-sources-of-energy |archive-date=15 January 2024 |date=2021 |url-status=live }} Data sources: Markandya & Wilkinson (2007); UNSCEAR (2008; 2018); Sovacool et al. (2016); IPCC AR5 (2014); Pehl et al. (2017); Ember Energy (2021).

}}

The largest cause of air pollution is fossil fuel combustion{{cite journal |last1=Vohra |first1=Karn |last2=Vodonos |first2=Alina |last3=Schwartz |first3=Joel |last4=Marais |first4=Eloise A. |last5=Sulprizio |first5=Melissa P. |last6=Mickley |first6=Loretta J. |date=1 April 2021 |title=Global mortality from outdoor fine particle pollution generated by fossil fuel combustion: Results from GEOS-Chem |url=https://www.sciencedirect.com/science/article/abs/pii/S0013935121000487 |journal=Environmental Research |language=en |volume=195 |page=110754 |bibcode=2021ER....19510754V |doi=10.1016/j.envres.2021.110754 |issn=0013-9351 |pmid=33577774 |s2cid=231909881 |access-date=5 March 2021}} – mostly the production and use of cars, electricity production, and heating.{{Cite web |date=June 22, 2021 |last1=Mackenzie |first1=Jillian |last2=Turrentine |first2=Jeff |title=Air Pollution: Everything You Need to Know |url=https://www.nrdc.org/stories/air-pollution-everything-you-need-know |access-date=2022-06-18 |website=NRDC }} There are estimated 4.5 million annual premature deaths worldwide due to pollutants released by high-emission power stations and vehicle exhausts.{{Cite book |last1=Farrow |first1=Aidan |url=https://www.greenpeace.org/static/planet4-southeastasia-stateless/2020/02/21b480fa-toxic-air-report-110220.pdf |title=Toxic air: The price of fossil fuels |last2=Miller |first2=Kathryn A |last3=Myllyvirta |first3=Lauri |date=February 2020 |publisher=Greenpeace Southeast Asia |location=Seoul}}

A study concluded that PM_2.5 air pollution induced by the contemporary free trade and consumption by the {{tooltip|2=the EU as a whole (not a nation) is not included here|19}} G20 nations causes two million premature deaths annually, suggesting that the average lifetime consumption of about ~28 people in these countries causes at least one premature death (average age ~67) while developing countries "cannot be expected" to implement or be able to implement countermeasures without external support or internationally coordinated efforts.{{cite news |title=Air pollution from G20 consumers caused two million deaths in 2010 |url=https://www.newscientist.com/article/2295873-air-pollution-from-g20-consumers-caused-two-million-deaths-in-2010/ |access-date=11 December 2021 |work=New Scientist}}{{cite journal |last1=Nansai |first1=Keisuke |last2=Tohno |first2=Susumu |last3=Chatani |first3=Satoru |last4=Kanemoto |first4=Keiichiro |last5=Kagawa |first5=Shigemi |last6=Kondo |first6=Yasushi |last7=Takayanagi |first7=Wataru |last8=Lenzen |first8=Manfred |title=Consumption in the G20 nations causes particulate air pollution resulting in two million premature deaths annually |journal=Nature Communications |date=2 November 2021 |volume=12 |issue=1 |page=6286 |doi=10.1038/s41467-021-26348-y |pmid=34728619 |pmc=8563796 |bibcode=2021NatCo..12.6286N |language=en |issn=2041-1723}}

The World Health Organization (WHO) estimates that cooking-related pollution causes 3.8 million annual deaths.{{Cite web |date=8 May 2018 |title=Household air pollution and health: fact sheet |url=https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health |access-date=2020-11-21 |website=WHO |language=en}} The Global Burden of Disease study estimated the number of deaths in 2021 at 3.1 million.{{cite journal |last1=Ritchie |first1=Hannah |author1-link=Hannah Ritchie |last2=Roser |first2=Max |author2-link=Max Roser |date=2024 |title=Access to Energy |url=https://ourworldindata.org/indoor-air-pollution#indoor-air-pollution-is-one-of-the-leading-risk-factors-for-premature-death |journal=Our World in Data |access-date=1 April 2021 |quote=}}

There is strong evidence that air pollution increases the risk of cardiovascular disease, including stroke, high blood pressure, and ischemic heart disease.{{cite journal |last1=de Bont |first1=Jeroen |last2=Jaganathan |first2=Suganthi |last3=Dahlquist |first3=Marcus |last4=Persson |first4=Åsa |last5=Stafoggia |first5=Massimo |last6=Ljungman |first6=Petter |date=8 March 2022 |title=Ambient air pollution and cardiovascular diseases: An umbrella review of systematic reviews and meta-analyses |url= |journal=Journal of Internal Medicine |volume=291 |issue=6 |pages=779–800 |doi=10.1111/joim.13467 |issn=0954-6820 |eissn=1365-2796 |pmc=9310863 |pmid=35138681}} According to the Global Burden of Disease Study, air pollution is responsible for 27% of deaths from strokes worldwide and 28% of ischemic heart disease.{{Cite book |last1=Health Effects Institute |author-link1=Health Effects Institute |url=https://www.stateofglobalair.org/resources/report/state-global-air-report-2024 |title=State of Global Air Report 2024: A Special Report on Global Exposure to Air Pollution and its Health Impacts with a Focus on Children's Health. |last2=Institute for Health Metrics and Evaluation |author-link2=Institute for Health Metrics and Evaluation |last3=UNICEF |author-link3=UNICEF |date=2024 |publisher=Health Effects Institute |page=27 |issn=2578-6873}} The risks are highest in regions with higher air pollution (i.e. Asia), for elderly and for people who are overweight.

Air pollution is a leading risk factor for stroke, particularly in developing countries where pollutant levels are highest. A systematic analysis of 17 different risk factors in 188 countries found air pollution is associated with nearly one in three strokes (29%) worldwide (34% of strokes in developing countries versus 10% in developed countries).{{cite journal |last1=Mayor |first1=Susan |date=12 June 2016 |title=Air pollution is a leading risk factor for stroke, global study shows |url= |journal=BMJ |volume=353 |page=i3272 |doi=10.1136/bmj.i3272 |eissn=1756-1833 |pmid=27298274}}{{cite journal | last1 = Feigin | first1 = Valery L | last2 = Roth | first2 = Gregory A | last3 = Naghavi | first3 = Mohsen | last4 = Parmar | first4 = Priya | last5 = Krishnamurthi | first5 = Rita | last6 = Chugh | first6 = Sumeet | last7 = Mensah | first7 = George A | last8 = Norrving | first8 = Bo | last9 = Shiue | first9 = Ivy | last10 = Ng | first10 = Marie | last11 = Estep | first11 = Kara | last12 = Cercy | first12 = Kelly | last13 = Murray | first13 = Christopher J L | last14 = Forouzanfar | first14 = Mohammad H | title = Global burden of stroke and risk factors in 188 countries, during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013 | journal = The Lancet Neurology | date = August 2016 | volume = 15 | issue = 9 | pages = 913–924 | issn = 1474-4422 | doi = 10.1016/S1474-4422(16)30073-4 | pmid = 27291521 | hdl = 10292/14061 | url = }} The mechanisms linking air pollution to increased cardiovascular mortality are not fully understood, but likely systemic inflammation and oxidative stress.{{Cite journal |last1=Montone |first1=Rocco A. |last2=Rinaldi |first2=Riccardo |last3=Bonanni |first3=Alice |last4=Severino |first4=Anna |last5=Pedicino |first5=Daniela |last6=Crea |first6=Filippo |last7=Liuzzo |first7=Giovanna |date=2023 |title=Impact of air pollution on ischemic heart disease: Evidence, mechanisms, clinical perspectives |url=https://linkinghub.elsevier.com/retrieve/pii/S0021915023000254 |journal=Atherosclerosis |language=en |volume=366 |pages=22–31 |doi=10.1016/j.atherosclerosis.2023.01.013|pmid=36696748 }}

Air pollution has been associated with increased hospitalization and mortality and COPD (chronic obstructive pulmonary disease).{{Cite journal |last1=Sin |first1=Don D. |last2=Doiron |first2=Dany |last3=Agusti |first3=Alvar |last4=Anzueto |first4=Antonio |last5=Barnes |first5=Peter J. |last6=Celli |first6=Bartolome R. |last7=Criner |first7=Gerard J. |last8=Halpin |first8=David |last9=Han |first9=MeiLan K. |last10=Martinez |first10=Fernando J. |last11=Montes de Oca |first11=Maria |last12=Papi |first12=Alberto |last13=Pavord |first13=Ian |last14=Roche |first14=Nicolas |last15=Singh |first15=Dave |date=2023 |title=Air pollution and COPD: GOLD 2023 committee report |url=https://publications.ersnet.org/content/erj/61/5/2202469 |journal=European Respiratory Journal |language=en |volume=61 |issue=5 |page=2202469 |doi=10.1183/13993003.02469-2022 |pmid=36958741 |issn=0903-1936}} COPD is a common disease which causes breathing difficulties and is the fourth-largest cause of death globally.{{Cite web |title=Chronic obstructive pulmonary disease (COPD) |url=https://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(copd) |access-date=2025-02-13 |website=World Health Organization }} Almost half of COPD deaths are due to air pollution. Fine particles (PM_2.5) or NO₂ were associated with increased risk of developing COPD.{{Cite journal |last1=Holtjer |first1=Judith C.S. |last2=Bloemsma |first2=Lizan D. |last3=Beijers |first3=Rosanne J.H.C.G. |last4=Cornelissen |first4=Merel E.B. |last5=Hilvering |first5=Bart |last6=Houweling |first6=Laura |last7=Vermeulen |first7=Roel C.H. |last8=Downward |first8=George S. |last9=Maitland-Van der Zee |first9=Anke-Hilse |date=2023-06-30 |title=Identifying risk factors for COPD and adult-onset asthma: an umbrella review |journal=European Respiratory Review |language=en |volume=32 |issue=168 |page=230009 |doi=10.1183/16000617.0009-2023 |issn=0905-9180 |pmc=10155046 |pmid=37137510}}

Air pollution is further associated with increased risk of asthma and worsening of symptoms, and this effect seems stronger in children.{{Cite journal |last1=Zhou |first1=Xiaoying |last2=Sampath |first2=Vanitha |last3=Nadeau |first3=Kari C. |date=2024 |title=Effect of air pollution on asthma |url=https://www.annallergy.org/article/S1081-1206(24)00018-8/fulltext |journal=Annals of Allergy, Asthma & Immunology |language=English |volume=132 |issue=4 |pages=426–432 |doi=10.1016/j.anai.2024.01.017 |pmid=38253122 |pmc=10990824 |issn=1081-1206 }} For adults, fine particles (PM_2.5) or NO₂ seem linked to asthma onset too.{{Cite journal |last1=Lee |first1=Spencer |last2=Tian |first2=Derek |last3=He |first3=Rose |last4=Cragg |first4=Jacquelyn J |last5=Carlsten |first5=Chris |last6=Giang |first6=Amanda |last7=Gill |first7=Prubjot K |last8=Johnson |first8=Kate M |last9=Brigham |first9=Emily |date=2024 |title=Ambient air pollution exposure and adult asthma incidence: a systematic review and meta-analysis |url=https://linkinghub.elsevier.com/retrieve/pii/S2542519624002791 |journal=The Lancet Planetary Health |language=en |volume=8 |issue=12 |pages=e1065–e1078 |doi=10.1016/S2542-5196(24)00279-1|pmid=39674196 }} Short-term exposure to ozone makes asthma worse in children.{{Cite book |last1=Health Effects Institute |author-link1=Health Effects Institute |url=https://www.stateofglobalair.org/resources/report/state-global-air-report-2024 |title=State of Global Air Report 2024: A Special Report on Global Exposure to Air Pollution and its Health Impacts with a Focus on Children's Health. |last2=Institute for Health Metrics and Evaluation |author-link2=Institute for Health Metrics and Evaluation |last3=UNICEF |author-link3=UNICEF |date=2024 |publisher=Health Effects Institute |page=18|issn=2578-6873}} There is limited evidence on (almost) fatal asthma attacks in children: ground-level ozone and PM_2.5 seem to increase its risk.{{Cite journal |last1=Varghese |first1=Deepa |last2=Ferris |first2=Kathryn |last3=Lee |first3=Bohee |last4=Grigg |first4=Jonathan |last5=Pinnock |first5=Hilary |last6=Cunningham |first6=Steve |date=2024 |title=Outdoor air pollution and near-fatal/fatal asthma attacks in children: A systematic review |url=https://onlinelibrary.wiley.com/doi/10.1002/ppul.26932 |journal=Pediatric Pulmonology |language=en |volume=59 |issue=5 |pages=1196–1206 |doi=10.1002/ppul.26932 |pmid=38477643 |issn=8755-6863}}

The risk of lung disease from air pollution is greatest for infants and young children, whose normal breathing is faster than that of older children and adults; the elderly; those who work outside or spend a lot of time outside; and those who have heart or lung disease comorbidities.{{Cite web |title=Understanding Air Pollution |url=https://resphealth.org/clean-air/understanding-air-pollution/ |access-date=2022-08-15 |website=Respiratory Health Association }}

File:DARK CLOUDS OF FACTORY SMOKE OBSCURE CLARK AVENUE BRIDGE - NARA - 550179.jpg

Around 265,000 lung cancer deaths were attributed globally in 2019 to exposure to fine particulate matter, PM_2.5, suspended in the air.{{Cite journal |last1=Berg |first1=Christine D. |last2=Schiller |first2=Joan H. |last3=Boffetta |first3=Paolo |last4=Cai |first4=Jing |last5=Connolly |first5=Casey |last6=Kerpel-Fronius |first6=Anna |last7=Kitts |first7=Andrea Borondy |last8=Lam |first8=David C. L. |last9=Mohan |first9=Anant |last10=Myers |first10=Renelle |last11=Suri |first11=Tejas |last12=Tammemagi |first12=Martin C. |last13=Yang |first13=Dawei |last14=Lam |first14=Stephen |date=2023-10-01 |title=Air Pollution and Lung Cancer: A Review by International Association for the Study of Lung Cancer Early Detection and Screening Committee |url=https://linkinghub.elsevier.com/retrieve/pii/S1556086423006019 |journal=Journal of Thoracic Oncology |language=English |volume=18 |issue=10 |pages=1277–1289 |doi=10.1016/j.jtho.2023.05.024 |issn=1556-0864 |pmid=37277094}} Exposure to indoor air pollution, including radon, caused another 170,000 lung cancer deaths. Lung cancer was also more common among people exposed to NO₂ and black carbon.{{Cite journal |last1=Karimi |first1=Behrooz |last2=Samadi |first2=Sadegh |date=2024 |title=Long-term exposure to air pollution on cardio-respiratory, and lung cancer mortality: a systematic review and meta-analysis |journal=Journal of Environmental Health Science & Engineering |volume=22 |issue=1 |pages=75–95 |doi=10.1007/s40201-024-00900-6 |issn=2052-336X |pmid=38887768|pmc=11180069 |bibcode=2024JEHSE..22...75K }}

Outdoor air pollution may increase risk of other types of cancer too, but the evidence is not as clear as for lung cancer.{{Cite journal |last1=Turner |first1=Michelle C. |last2=Andersen |first2=Zorana J. |last3=Baccarelli |first3=Andrea |last4=Diver |first4=W. Ryan |last5=Gapstur |first5=Susan M. |last6=Pope |first6=C. Arden |last7=Prada |first7=Diddier |last8=Samet |first8=Jonathan |last9=Thurston |first9=George |last10=Cohen |first10=Aaron |date=2020-08-25 |title=Outdoor air pollution and cancer: An overview of the current evidence and public health recommendations |journal=CA: A Cancer Journal for Clinicians |volume=70 |issue=6 |pages=460–479 |doi=10.3322/caac.21632 |issn=1542-4863 |pmc=7904962 |pmid=32964460}} For instance, there may be a relationship between kidney cancer and PM_2.5 and NO₂ levels.{{Cite journal |last1=Dahman |first1=Lina |last2=Gauthier |first2=Victoria |last3=Camier |first3=Aurore |last4=Bigna |first4=Jean Joel |last5=Glowacki |first5=François |last6=Amouyel |first6=Philippe |last7=Dauchet |first7=Luc |last8=Hamroun |first8=Aghiles |date=2024 |title=Air pollution and kidney cancer risk: a systematic review and meta-analysis |journal=Journal of Nephrology |volume=37 |issue=7 |pages=1779–1790 |doi=10.1007/s40620-024-01984-x |issn=1724-6059 |pmid=38913266|pmc=11519201 }} Household air pollution, for instance from cooking with solid fuels, but also from radon in building material, has been associated with cervical, oral, and esophageal cancer.

Stillbirths, miscarriages and birth defects are all more likely when the mother is exposed to air pollution during pregnancy. Exposure to air pollution also raises the chance a baby has a low birth weight. The impacts might be due to pollutants directly impacting the placenta or fetus, or indirectly via the mother's health (as air pollution can cause systemic inflammation and oxidative stress).

Over a third of preterm births were associated with air pollution in 2021 globally. It causes more than half a million newborn deaths, a quarter of overall deaths. The source of PM_2.5 differs greatly by region. In South and East Asia, pregnant women are frequently exposed to indoor air pollution because of wood and other biomass fuels being used for cooking, which are responsible for more than 80% of regional pollution. In the Middle East, North Africa and West sub-Saharan Africa, fine PM comes from natural sources, such as dust storms.{{Cite journal |last1=Malley |first1=Christopher S. |last2=Kuylenstierna |first2=Johan C. I. |last3=Vallack |first3=Harry W. |last4=Henze |first4=Daven K. |last5=Blencowe |first5=Hannah |last6=Ashmore |first6=Mike R. |date=1 April 2017 |title=Preterm birth associated with maternal fine particulate matter exposure: A global, regional and national assessment |url=http://eprints.whiterose.ac.uk/112553/1/Malley_2017_Environment_International.pdf |journal=Environment International |volume=101 |pages=173–82 |bibcode=2017EnInt.101..173M |doi=10.1016/j.envint.2017.01.023 |issn=1873-6750 |pmid=28196630 |doi-access=free}}

Including older children, polluted air leads resulted in the death of over 700,000 children in 2021 (709,000 under 5 years of age and 16,600 aged 5–14 years).{{Cite book |last1=Health Effects Institute |author-link1=Health Effects Institute |url=https://www.stateofglobalair.org/resources/report/state-global-air-report-2024 |title=State of Global Air Report 2024: A Special Report on Global Exposure to Air Pollution and its Health Impacts with a Focus on Children's Health. |last2=Institute for Health Metrics and Evaluation |author-link2=Institute for Health Metrics and Evaluation |last3=UNICEF |author-link3=UNICEF |date=2024 |publisher=Health Effects Institute |pages=21–23 |issn=2578-6873}} Children in low- or middle-income countries are exposed to higher levels of fine particulate matter than those in high income countries.{{Cite book |url=https://www.who.int/publications/i/item/air-pollution-and-child-health |title=Air pollution and child health: prescribing clean air. Summary. |date=2018 |publisher=World Health Organization |location=Geneva |pages=2–6}} Further health effects of air pollution on children include asthma, pneumonia and lower respiratory tract infections.{{Cite book |last1=Gordon |first1=Bruce |url=https://www.who.int/publications/i/item/9241591560 |title=Inheriting the World: The Atlas of Children's Health and the Environment |last2=Mackay |first2=Richard |last3=Rehfuess |first3=Eva |date=2004 |publisher=World Health Organization |chapter=Polluted Cities: The Air Children Breathe}} There is possibly a link between exposure to air pollution during pregnancy and after birth and autism in children.{{Cite journal |last1=Dutheil |first1=Frédéric |last2=Comptour |first2=Aurélie |last3=Morlon |first3=Roxane |last4=Mermillod |first4=Martial |last5=Pereira |first5=Bruno |last6=Baker |first6=Julien S. |last7=Charkhabi |first7=Morteza |last8=Clinchamps |first8=Maëlys |last9=Bourdel |first9=Nicolas |date=2021-06-01 |title=Autism spectrum disorder and air pollution: A systematic review and meta-analysis |url=https://linkinghub.elsevier.com/retrieve/pii/S0269749121004383 |journal=Environmental Pollution |language=en |volume=278 |page=116856 |doi=10.1016/j.envpol.2021.116856|pmid=33714060 |bibcode=2021EPoll.27816856D }}{{Cite journal |last1=Kang |first1=Ni |last2=Sargsyan |first2=Suzan |last3=Chough |first3=Ino |last4=Petrick |first4=Lauren |last5=Liao |first5=Jiawen |last6=Chen |first6=Wu |last7=Pavlovic |first7=Nathan |last8=Lurmann |first8=Frederick W. |last9=Martinez |first9=Mayra P. |last10=McConnell |first10=Rob |last11=Xiang |first11=Anny H. |last12=Chen |first12=Zhanghua |date=2024-11-15 |title=Dysregulated metabolic pathways associated with air pollution exposure and the risk of autism: Evidence from epidemiological studies |journal=Environmental Pollution |volume=361 |page=124729 |doi=10.1016/j.envpol.2024.124729 |pmid=39147228 |pmc=11902886 |issn=0269-7491}}

{{see also|Brain health and pollution}}

Air pollution is linked to various diseases of the brain. Indoor air pollution exposure during childhood may negatively affect cognitive function and neurodevelopment.{{cite journal |last1=Julvez |first1=Jordi |last2=López-Vicente |first2=Mónica |last3=Warembourg |first3=Charline |last4=Maitre |first4=Lea |last5=Philippat |first5=Claire |last6=Gützkow |first6=Kristine B. |last7=Guxens |first7=Monica |last8=Evandt |first8=Jorunn |last9=Andrusaityte |first9=Sandra |last10=Burgaleta |first10=Miguel |last11=Casas |first11=Maribel |last12=Chatzi |first12=Leda |last13=de Castro |first13=Montserrat |last14=Donaire-González |first14=David |last15=Gražulevičienė |first15=Regina |last16=Hernandez-Ferrer |first16=Carles |last17=Heude |first17=Barbara |last18=Mceachan |first18=Rosie |last19=Mon-Williams |first19=Mark |last20=Nieuwenhuijsen |first20=Mark |last21=Robinson |first21=Oliver |last22=Sakhi |first22=Amrit K. |last23=Sebastian-Galles |first23=Nuria |last24=Slama |first24=Remy |last25=Sunyer |first25=Jordi |last26=Tamayo-Uria |first26=Ibon |last27=Thomsen |first27=Cathrine |last28=Urquiza |first28=Jose |last29=Vafeiadi |first29=Marina |last30=Wright |first30=John |last31=Basagaña |first31=Xavier |last32=Vrijheid |first32=Martine |title=Early life multiple exposures and child cognitive function: A multi-centric birth cohort study in six European countries |journal=Environmental Pollution |date=1 September 2021 |volume=284 |page=117404 |doi=10.1016/j.envpol.2021.117404 |pmid=34077897 |pmc=8287594 |bibcode=2021EPoll.28417404J |language=en |issn=0269-7491}}{{cite journal |last1=Costa |first1=Lucio G. |last2=Cole |first2=Toby B. |last3=Dao |first3=Khoi |last4=Chang |first4=Yu-Chi |last5=Coburn |first5=Jacki |last6=Garrick |first6=Jacqueline M. |date=June 2020 |title=Effects of air pollution on the nervous system and its possible role in neurodevelopmental and neurodegenerative disorders |journal=Pharmacology & Therapeutics |volume=210 |page=107523 |doi=10.1016/j.pharmthera.2020.107523 |issn=1879-016X |pmc=7245732 |pmid=32165138}} Prenatal exposure may also affect neurodevelopment.{{cite journal |last1=Volk |first1=Heather E. |last2=Perera |first2=Frederica |last3=Braun |first3=Joseph M. |last4=Kingsley |first4=Samantha L. |last5=Gray |first5=Kimberly |last6=Buckley |first6=Jessie |last7=Clougherty |first7=Jane E. |last8=Croen |first8=Lisa A. |last9=Eskenazi |first9=Brenda |last10=Herting |first10=Megan |last11=Just |first11=Allan C. |last12=Kloog |first12=Itai |last13=Margolis |first13=Amy |last14=McClure |first14=Leslie A. |last15=Miller |first15=Rachel |last16=Levine |first16=Sarah |last17=Wright |first17=Rosalind |title=Prenatal air pollution exposure and neurodevelopment: A review and blueprint for a harmonized approach within ECHO |journal=Environmental Research |date=1 May 2021 |volume=196 |page=110320 |doi=10.1016/j.envres.2020.110320 |pmid=33098817 |pmc=8060371 |bibcode=2021ER....19610320V |language=en |issn=0013-9351}}{{cite journal |last1=Shang |first1=Li |last2=Yang |first2=Liren |last3=Yang |first3=Wenfang |last4=Huang |first4=Liyan |last5=Qi |first5=Cuifang |last6=Yang |first6=Zixuan |last7=Fu |first7=Zhuxuan |last8=Chung |first8=Mei Chun |title=Effects of prenatal exposure to NO₂ on children's neurodevelopment: a systematic review and meta-analysis |journal=Environmental Science and Pollution Research |date=1 July 2020 |volume=27 |issue=20 |pages=24786–24798 |doi=10.1007/s11356-020-08832-y |pmc=7329770 |pmid=32356052 |bibcode=2020ESPR...2724786S |s2cid=216650267 |language=en |issn=1614-7499}} It may also contribute to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. There are various routes by which air pollution could cause brain damage: it can cause neuroinflammation, or secondary effects from lung inflammation. At the same time, it can cause cardiovascular disease which in itself raises the risk of brain diseases.

Exposure to air pollution may also drive mental health issues, such as depression and anxiety.{{Cite journal |last1=Cao |first1=Tingting |last2=Tian |first2=Meichen |last3=Hu |first3=Han |last4=Yu |first4=Qingqing |last5=You |first5=Jing |last6=Yang |first6=Yishu |last7=An |first7=Zhen |last8=Song |first8=Jie |last9=Zhang |first9=Guofu |last10=Zhang |first10=Guicheng |last11=Wu |first11=Weidong |last12=Wu |first12=Hui |date=2024-03-01 |title=The relationship between air pollution and depression and anxiety disorders – A systematic evaluation and meta-analysis of a cohort-based study |url=https://journals.sagepub.com/doi/10.1177/00207640231197941?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed |journal=International Journal of Social Psychiatry |language=en |volume=70 |issue=2 |pages=241–270 |doi=10.1177/00207640231197941 |pmid=37753871 |issn=0020-7640}} In particular, air pollution from the use of solid fuels was associated with a higher depression risk.{{Cite journal |last1=Zhang |first1=Xiaona |last2=Ding |first2=Linlin |last3=Yang |first3=Fen |last4=Qiao |first4=Guiyuan |last5=Gao |first5=Xiaolian |last6=Xiong |first6=Zhenfang |last7=Zhu |first7=Xinhong |date=2024-05-08 |title=Association between indoor air pollution and depression: a systematic review and meta-analysis of cohort studies |journal=BMJ Open |volume=14 |issue=5 |pages=e075105 |doi=10.1136/bmjopen-2023-075105 |issn=2044-6055 |pmid=38719299|pmc=11086541 }} Depression risk and suicide was more strongly linked to finer particulate matter (PM2.5), compared to coarser particles (PM10). The association was strongest for people over the age of 65.{{Cite journal |last1=Liu |first1=Qisijing |last2=Wang |first2=Wanzhou |last3=Gu |first3=Xuelin |last4=Deng |first4=Furong |last5=Wang |first5=Xueqin |last6=Lin |first6=Hualiang |last7=Guo |first7=Xinbiao |last8=Wu |first8=Shaowei |date=2021 |title=Association between particulate matter air pollution and risk of depression and suicide: a systematic review and meta-analysis |journal=Environmental Science and Pollution Research International |volume=28 |issue=8 |pages=9029–9049 |doi=10.1007/s11356-021-12357-3 |issn=1614-7499 |pmid=33481201|bibcode=2021ESPR...28.9029L }}

Problems with thinking (cognitive issues) are also associated with air pollution. In people over the age of 40, both NO_x and PM_2.5 have been linked to general cognitive problems. PM_2.5 was also associated with reduced verbal fluency (for instance, number of animals one can list in a minute) and worse executive functions (like attention and working memory). Similarly, children tended to fare worse in tests involving working memory when there was NO_x, PM_2.5, or PM₁₀ pollution.{{Cite journal |last1=Thompson |first1=Rhiannon |last2=Smith |first2=Rachel B. |last3=Karim |first3=Yasmin Bou |last4=Shen |first4=Chen |last5=Drummond |first5=Kayleigh |last6=Teng |first6=Chloe |last7=Toledano |first7=Mireille B. |date=2023-02-10 |title=Air pollution and human cognition: A systematic review and meta-analysis |url=https://linkinghub.elsevier.com/retrieve/pii/S004896972207334X |journal=Science of the Total Environment |volume=859 |issue=Pt 2 |page=160234 |doi=10.1016/j.scitotenv.2022.160234 |pmid=36427724 |bibcode=2023ScTEn.85960234T |hdl=10044/1/101759 |issn=0048-9697}}

File:Pollution - Damaged by acid rain.jpg

File:Acid rain woods1.JPG, Czech Republic.|alt=dead tree trunks which have lost all their leafs]]

Naturally, water in the atmosphere is slightly acidic. Some pollutants can form strong acids, making rainwater much more acidic. Key acids that cause acid rain are nitric acid (HNO₃), sulfuric acid (H₂SO₄) and hydrochloric acid (HCl). HCl comes from coal combustion. H₂SO₄ forms from SO₂, which comes from the burning of coal and oil and from some industrial processes like smelting. HNO₃ froms from NO₂, which is formed during high-temperature combustion. The term acid rain not only refers to rain, but also to pollution from hail, fog and snow.{{Citation |title=Environmental Impacts |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |pages=306–308 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/air-pollution/environmental-impacts/8F47851775A4681857CEB599B3C32DF5 |access-date=2025-06-04 |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.013 |isbn=978-1-108-48163-2}}

Acid rain caused substantial damage in the 1970, including lake acidification and forest diebacks in Northern Europe. Due the changed acidicity in water bodies and soils, essential nutrients such as magnesium and calcium became soluble and could be washed away. Other elements, such as aluminium, which were toxic to vegetation, became available for the roots to absorb. Acid rain also impacts buildings and statues made of specific stones (e.g. marble, calcite or freestone), as the stone reacts chemically with the acid in the water and erodes.

Air pollution can settle (deposit) on the soil or in water, causing various problems. For instance, ammonia and nitric acid in the air can contribute to nutrient pollution in the water, a process called eutrophication. At first, the extra nutrients help plants grow, but dense plant growth blocks sunlight from reaching the bottom. Plants in the lower layers then die, and with fewer plants producing oxygen, the oxygen level drops. This harms organisms that need oxygen to live.{{Citation |title=Environmental Impacts |date=2019 |work=Air Pollution: Concepts, Theory, and Applications |pages=308–309 |editor-last=Seigneur |editor-first=Christian |url=https://www.cambridge.org/core/books/air-pollution/environmental-impacts/8F47851775A4681857CEB599B3C32DF5 |access-date=2025-06-04 |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/9781108674614.013 |isbn=978-1-108-48163-2}}

Various studies have estimated the impacts of air pollution on agriculture, especially ozone. Ozone acts as an oxidant and reduces photosynthesis. One study estimated that for a 1% increase in ozone concentrations, there would be a global economic loss of $10 billion each year. For PM_2.5, a 1% increase in pollution levels would lead to around $5 billion in losses, especially in colder climates.{{cite journal|url=https://www.sciencedirect.com/science/article/pii/S0160412023001150|title=Air pollution as a substantial threat to the improvement of agricultural total factor productivity: Global evidence|last1=Dong|first1=Daxin|last2=Wang|first2=Jiaxin|journal=Environment International|volume=173|date=2023|doi=10.1016/j.envint.2023.107842|pmid=36863165 |bibcode=2023EnInt.17307842D }} After air pollutants enter the agricultural environment, they not only directly affect agricultural production and quality, but also enter agricultural waters and soil.{{Cite journal |last1=Li |first1=Houjian |last2=Tang |first2=Mengqian |last3=Cao |first3=Andi |last4=Guo |first4=Lili |date=2022 |title=Assessing the relationship between air pollution, agricultural insurance, and agricultural green total factor productivity: evidence from China |url=https://link.springer.com/10.1007/s11356-022-21287-7 |journal=Environmental Science and Pollution Research |language=en |volume=29 |issue=52 |pages=78381–78395 |doi=10.1007/s11356-022-21287-7 |pmid=35689771 |bibcode=2022ESPR...2978381L |s2cid=249551277 |issn=0944-1344}} Air pollution further decreases the productivity of labourers via health impacts.

The COVID-19 lockdowns served as a natural experiment to expose the close links between air quality and surface greenness. In India, the lockdown induced improvement in air quality, enhanced surface greenness and photosynthetic activity, with the positive response of vegetation to reduce air pollution was dominant in croplands.{{Cite journal |last1=Kashyap |first1=Rahul |last2=Kuttippurath |first2=J. |last3=Patel |first3=V. K. |date=2023 |title=Improved air quality leads to enhanced vegetation growth during the COVID–19 lockdown in India |journal=Applied Geography |language=en |volume=151 |page=102869 |doi=10.1016/j.apgeog.2022.102869 |pmid=36619606 |pmc=9805897 |bibcode=2023AppGe.15102869K |s2cid=255439854 |issn=0143-6228}} On the other hand, agriculture in its traditional form is one of the primary contributors to the emission of trace gases like atmospheric ammonia.{{Cite journal|last1=Kuttippurath |first1=J. |last2=Singh |first2=A. |last3=Dash |first3=S. P. |last4=Mallic |first4=N. |last5=Clerbaux |first5=C. |last6=Van Damme |first6=M. |last7=Clarisse |first7=L. |last8=Coheur |first8=P.-F. |last9=Raj |first9=S. |last10=Abbhishek |first10=K. |last11=Varikoden |first11=H.|date=2020 |title=Record high levels of atmospheric ammonia over India: Spatial and temporal analyses |url=https://www.sciencedirect.com/science/article/pii/S0048969720335063 |journal=Science of the Total Environment |language=en |volume=740 |page=139986 |doi=10.1016/j.scitotenv.2020.139986 |pmid=32927535 |bibcode=2020ScTEn.74039986K |s2cid=221722300 |issn=0048-9697}}

Air pollution has a strong impact on the economy via its health effects (such as reduced productivity at work and the costs of healthcare) and its effects on crop yield. It also affects tourism, biodiversity, forestry and water quality. For instance, tourism may be negatively affected due to decreased visibility and damage to cultural heritage.{{Cite book |last=OECD |url=https://www.oecd.org/content/dam/oecd/en/publications/reports/2016/06/the-economic-consequences-of-outdoor-air-pollution_g1g68583/9789264257474-en.pdf |title=The Economic Consequences of Outdoor Air Pollution |publisher=OECD Publishing |year=2016 |location=Paris |pages=22 |doi=10.1787/9789264257474-en|isbn=978-92-64-25746-7 }} People may be more prone to accidents due to air pollution. For instance, increased NO₂ levels are linked to construction site accidents.{{cite report |url=https://www.nber.org/papers/w30715 |title=Heads Up: Does Air Pollution Cause Workplace Accidents? |last1=Lavy |first1=Victor |last2=Rachkovski |first2=Genia |last3=Yoresh |first3=Omry |year=2022 |publisher=National Bureau of Economic Research |doi=10.3386/w30715 |page= |publication-place=Cambridge, MA}}

In terms the welfare cost on human health (non-market costs), a World Bank study found that PM_2.5 pollution in 2019 cost the world economy over $8 trillion, over 6% of global GDP. In India and China, the loss of GDP was over 10%. Around 85% of this loss globally came from the loss of life, the rest from increased ill health.{{Cite book |last=World Bank |url=https://documents1.worldbank.org/curated/en/455211643691938459/pdf/The-Global-Health-Cost-of-PM-2-5-Air-Pollution-A-Case-for-Action-Beyond-2021.pdf |title=The Global Health Cost of PM2.5 Air Pollution: A Case for Action Beyond 2021 |date=2022-04-12 |publisher=The World Bank |isbn=978-1-4648-1816-5 |language=en |doi=10.1596/978-1-4648-1816-5|hdl=10986/36501 }}{{Rp|page=|pages=23-24}} The costs of lives lost are calculated using the Value of Statistical Life, a number that tries to estimate how much people would be willing to pay to reduce their risk of dying.{{Rp|page=xiii|pages=}} This number differs by country and is difficult to estimate for low- and middle-income countries.{{Cite journal |last1=Wang |first1=Siyuan |last2=Song |first2=Rong |last3=Xu |first3=Zhiwei |last4=Chen |first4=Mingsheng |last5=Di Tanna |first5=Gian Luca |last6=Downey |first6=Laura |last7=Jan |first7=Stephen |last8=Si |first8=Lei |date=2024-08-21 |title=The costs, health and economic impact of air pollution control strategies: a systematic review |journal=Global Health Research and Policy |language=en |volume=9 |issue=1 |page=30 |doi=10.1186/s41256-024-00373-y |issn=2397-0642 |pmc=11337783 |pmid=39164785 |doi-access=free}}

The direct market impacts on productivity loss, healthcare use and crop losses were estimated to rise to 1% of GDP by 2060, according to the OECD. The Caspian region and China would see the largest impact.{{Cite book |last=OECD |url=https://www.oecd.org/content/dam/oecd/en/publications/reports/2016/06/the-economic-consequences-of-outdoor-air-pollution_g1g68583/9789264257474-en.pdf |title=The Economic Consequences of Outdoor Air Pollution |publisher=OECD Publishing |year=2016 |location=Paris |pages=14–15 |doi=10.1787/9789264257474-en|isbn=978-92-64-25746-7 }} Air pollution also has an impact on energy production, as it reduces the amount of sunlight that reaches solar panels. It also causes the panels to become dirty, further reducing their energy output.{{Cite journal |last1=Song |first1=Zhe |last2=Liu |first2=Jia |last3=Yang |first3=Hongxing |date=2021-09-15 |title=Air pollution and soiling implications for solar photovoltaic power generation: A comprehensive review |url=https://www.sciencedirect.com/science/article/abs/pii/S030626192100667X |journal=Applied Energy |volume=298 |pages=117247 |doi=10.1016/j.apenergy.2021.117247 |bibcode=2021ApEn..29817247S |hdl=10397/102795 |issn=0306-2619}}

Mummified remains of people in Peru, Egypt and Britain show that ancient people in these regions suffered from blackening of the lungs caused by open fires in poorly ventilated homes. Recorded complaints of air pollution go back to the Greek and Roman period. Outdoor air pollution became a problem with the rise of cities, caused by household smoke and by early industrial activities (such as smelting and mining). In particular, lead levels, found in Arctic ice cores, were about ten times higher in the Roman period than in the period before.{{Citation |last=Mosley |first=Stephen |title=Environmental History of Air Pollution and Protection |date=2014 |work=The Basic Environmental History |volume=4 |pages=144–148 |editor-last=Agnoletti |editor-first=Mauro |url=https://link.springer.com/chapter/10.1007/978-3-319-09180-8_5 |access-date=2025-03-29 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-09180-8_5 |isbn=978-3-319-09179-2 |editor2-last=Neri Serneri |editor2-first=Simone}}

During the Industrial Revolution, outdoor air pollution started to rise strongly, mostly due to the large-scale burning of coal. This occurred first in Britain, then in the rest of Northern Europe and the United States. By the 19th century, buildings around industrial plants started to blacken, while plants and trees in public parks started to wither. Smoke-induced fogs reduced the amount of sunlight city-dwellers got, contributing to cases of rickets, a childhood disease caused by lack of sunlight and poor diet.{{Citation |last=Mosley |first=Stephen |title=Environmental History of Air Pollution and Protection |date=2014 |work=The Basic Environmental History |volume=4 |pages=148–156 |editor-last=Agnoletti |editor-first=Mauro |url=https://link.springer.com/chapter/10.1007/978-3-319-09180-8_5 |access-date=2025-03-29 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-09180-8_5 |isbn=978-3-319-09179-2 |editor2-last=Neri Serneri |editor2-first=Simone}}

File:Smoke of chimneys is the breath of Soviet Russia.jpg

In the 1830s, anti-smoke groups emerged in Britain, followed by groups in the United States in the 1880s. Legislation against pollution was weak however, as it was seen to conflict with industrial interests. During the Interwar period, a move towards gas and oil meant there was less air pollution, but this trend reversed when World War II broke out. The United Kingdom suffered its worst air pollution during the 1952 Great Smog of London, with some 12,000 deaths, which led to the Clean Air Act 1956.{{cite journal |last1=Bell |first1=Michelle L. |last2=Davis |first2=Devra L. |last3=Fletcher |first3=Tony |date=January 2004 |title=A Retrospective Assessment of Mortality from the London Smog Episode of 1952: The Role of Influenza and Pollution |journal=Environ Health Perspect |volume=112 |issue=1 |pages=6–8 |bibcode=2004EnvHP.112....6B |doi=10.1289/ehp.6539 |pmc=1241789 |pmid=14698923 |s2cid=13045119}} The 1948 Donora Smog in the US, killing 20 people, prompted the US to start regulating air pollution.{{cite book |last=Davis |first=Devra |url=https://archive.org/details/whensmokeranlike00davi |title=When Smoke Ran Like Water: Tales of Environmental Deception and the Battle Against Pollution |publisher=Basic Books |year=2002 |isbn=978-0-465-01521-4 |url-access=registration}} Japan followed in the 1960, but other heavily-polluted regions, such as the Soviet Union and China, did not implement effective regulation.

Technological disasters have caused severe problems with air pollution. The world's worst pollution disaster was the 1984 Bhopal Disaster in India. Leaked industrial vapours from the Union Carbide factory (later bought by Dow Chemical Company), killed at least 20,000 people and affected around 600,000.{{Citation |last=Silei|first=Gianni |title=Environmental History of Air Pollution and Protection |date=2014 |work=The Basic Environmental History |volume=4 |pages=248–249|editor-last=Agnoletti |editor-first=Mauro |url=https://link.springer.com/chapter/10.1007/978-3-319-09180-8_8 |access-date=2025-03-29 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-09180-8_8 |isbn=978-3-319-09179-2 |editor2-last=Neri Serneri |editor2-first=Simone}} An accidental leak of anthrax spores from a biological warfare laboratory in the former USSR in 1979 is believed to have caused at least 64 deaths.{{cite journal |vauthors=Meselson M, Guillemin J, Hugh-Jones M |title=The Sverdlovsk anthrax outbreak of 1979 |journal=Science |volume=266 |issue=5188 |pages=1202–08 |date=November 1994 |pmid=7973702 |doi=10.1126/science.7973702 |url=http://www.anthrax.osd.mil/documents/library/Sverdlovsk.pdf |archive-url=https://web.archive.org/web/20060921004004/http://www.anthrax.osd.mil/documents/library/Sverdlovsk.pdf |archive-date=21 September 2006 |bibcode=1994Sci...266.1202M}}

From the 1950s, smog in developed countries was regulated, but other pollutants were not. Acid rain, caused by sulphur dioxide, became a major issue as it spread across borders. In the 1990s, for instance, Japan experienced acid rain from Chinese and Korean industry. International cooperation was needed to curb acid rain, and various coalitions were started. In 1975, it was discovered that certain chemicals caused a hole in the ozone layer; thanks to succesfull international negotiations, these chemicals were banned worldwide in the 1987 Montreal Protocol. There has been far less success in curbing greenhouse gas emissions, mostly from the production and burning of fossil fuels. The 1997 Kyoto Protocol introduced modest reduction targets but lacked strong enforcement,{{Citation |last=Mosley |first=Stephen |title=Technological Hazards, Disasters and Accidents |date=2014 |work=The Basic Environmental History |volume=4 |pages=156–165 |editor-last=Agnoletti |editor-first=Mauro |url=https://link.springer.com/chapter/10.1007/978-3-319-09180-8_5 |access-date=2025-03-29 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-09180-8_5 |isbn=978-3-319-09179-2 |editor2-last=Neri Serneri |editor2-first=Simone}} while the 2015 Paris Agreement set no binding limits, instead encouraging countries to raise their ambition over time.{{Cite journal |last1=Raiser |first1=Kilian |last2=Kornek |first2=Ulrike |last3=Flachsland |first3=Christian |last4=Lamb |first4=William F |date=2020-08-01 |title=Is the Paris Agreement effective? A systematic map of the evidence |url=https://iopscience.iop.org/article/10.1088/1748-9326/ab865c |journal=Environmental Research Letters |volume=15 |issue=8 |pages=083006 |bibcode=2020ERL....15h3006R |doi=10.1088/1748-9326/ab865c |issn=1748-9326}}

{{Further|Air pollution measurement| Environmental monitoring}}File:New Delhi Met Office, India 02.jpg|alt=Display showing poor air quality for PM2.5 and PM10]]Air pollution can be monitored using different techniques. For instance, satellites and remote sensing is used to track PM, NO₂ and ozone.{{Cite web |title=Air Quality from Space |url=https://airquality.gsfc.nasa.gov/ |access-date=2025-02-23 |website=airquality.gsfc.nasa.gov}} Many regions have a network of monitoring stations, with good coverage in India, China, Europe and the US. Poor coverage exist however for a number of highly-polluted countries, such as Chad and Iran. The density of measurements is improving as there are more low-cost techniques to measure air pollution.{{Cite report |url=https://www.iqair.com/dl/2023_World_Air_Quality_Report.pdf |title=2023 World Air Quality Report |last=IQAir |author-link=IQAir |date=2024 |page=11}} Low-cost monitors can also be used for indoor air quality monitoring.{{Cite web |last=US EPA |date=2019-09-16 |title=Low–Cost Air Pollution Monitors and Indoor Air Quality |url=https://www.epa.gov/indoor-air-quality-iaq/low-cost-air-pollution-monitors-and-indoor-air-quality |access-date=2025-02-23 |website=www.epa.gov |language=en}} Finally, air quality sensors can be incorporated into drones to measure air pollution higher up in the air.{{Cite web |title=Monitoring ambient air: choosing a monitoring technique and method |url=https://www.gov.uk/guidance/monitoring-ambient-air-choosing-a-monitoring-technique-and-method |access-date=2025-02-23 |website=GOV.UK |language=en}} Some websites attempt to map air pollution levels using available data.{{cite web |title=World Air Map: Live air quality everywhere in the world |url=https://air.plumelabs.com/en/ |access-date=20 December 2021 |website=Plume Labs Air Report}}{{cite web |title=Live Animated Air Quality Map (AQI, PM2.5...) {{!}} AirVisual |url=https://www.iqair.com/air-quality-map |access-date=27 January 2022 |publisher=IQAir}}

Air quality indexes (AQIs) offer a simple way for governments to communicate changes in air quality and associated health risks, especially during short-term pollution episodes, such as wildfires.{{cite web |title=Daily Air Quality Index |url=https://uk-air.defra.gov.uk/air-pollution/daqi |access-date=17 January 2025 |website=UK Air |publisher=Department for Environment, Food, and Rural Affairs}} An AQI is essentially a health protection tool people can use to help reduce their short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. Examples include Canada's Air Quality Health Index (AQHI),{{Cite web |last=Canada |first=Environment and Climate Change |date=2007-09-10 |title=About the Air Quality Health Index |url=https://www.canada.ca/en/environment-climate-change/services/air-quality-health-index/about.html |access-date=2022-02-27 |website=Canada.ca}} Malaysia's Air Pollution Index, and Singapore's Pollutant Standards Index.

{{Main|Air quality modeling}}

File:Portrait_of_Global_Aerosols.jpeg and white shows sulphate particle pollution.]]

When direct data is unavailable or when projecting future air pollutant levels, estimates can be derived using models or emission factors.{{Cite book |last=Vallero |first=Daniel A. |title=Fundamentals of Air Pollution |date=2014 |publisher=Academic Press |isbn=978-0-12-401733-7|edition=5th|page=704, 822}} Air pollutant emission factors are typical values that link the amount of a pollutant released into the air to a related activity. This could for instance be the typical amount of particulate matter released from a coal-power station.{{Cite web |last=Environment and Climate Change Canada |title=Air pollutant emissions |url=https://www.canada.ca/en/environment-climate-change/services/environmental-indicators/air-pollutant-emissions.html |access-date=2022-06-07 |website=Canada.ca|date=14 June 2010}} The United States Environmental Protection Agency has published a compilation of air pollutant emission factors for a wide range of industrial sources,{{cite web |title=AP 42, Volume I |url=http://www.epa.gov/ttn/chief/ap42/index.html |url-status=live |archive-url=https://web.archive.org/web/20100924132127/http://www.epa.gov/ttn/chief/ap42/index.html |archive-date=24 September 2010 |access-date=29 August 2010 |website=US Environmental Protection Agency}} as well as the European Environment Agency.{{cite web |date=19 June 2009 |title=EMEP/EEA air pollutant emission inventory guidebook—2009 |url=http://www.eea.europa.eu/publications/emep-eea-emission-inventory-guidebook-2009 |access-date=11 December 2012 |website=Eea.europa.eu |publisher=European Environmental Agency}}

Air quality models use meteorological and emissions data to simulate how pollutants disperse and react in the atmosphere. Regulatory agencies use them to assess whether a new source of air pollution would exceed acceptable pollution levels, for permitting purposes. They can also be used to predict future pollution levels under different policy scenarios.{{Cite web |last=US EPA |date=2016-07-14 |title=Air Quality Models |url=https://www.epa.gov/scram/air-quality-models |access-date=2025-04-19 |website=www.epa.gov |language=en}} There are models for local pollution, but also for cross-boundary pollution.{{Cite web |date=2016 |title=Air Pollution Modelling |url=https://www.apis.ac.uk/air-pollution-modelling |access-date=2025-04-19 |website= |publisher=Air Pollution Information System}}

Pollution prevention seeks to prevent pollution such as air pollution and could include adjustments to industrial and business activities such as designing sustainable manufacturing processes (and the products' designs){{cite journal |last1=Camahan |first1=James V. |last2=Thurston |first2=Deborah L. |author2-link=Deborah Thurston |title=Trade-off Modeling for Product and Manufacturing Process Design for the Environment |journal=Journal of Industrial Ecology |date=1998 |volume=2 |issue=1 |pages=79–92 |doi=10.1162/jiec.1998.2.1.79 |bibcode=1998JInEc...2...79C |s2cid=154730593 |language=en |issn=1530-9290}} and related legal regulations as well as efforts towards renewable energy transitions.{{cite journal |last1=Jacobson |first1=Mark Z. |last2=von Krauland |first2=Anna-Katharina |last3=Coughlin |first3=Stephen J. |last4=Palmer |first4=Frances C. |last5=Smith |first5=Miles M. |title=Zero air pollution and zero carbon from all energy at low cost and without blackouts in variable weather throughout the U.S. with 100% wind-water-solar and storage |journal=Renewable Energy |date=1 January 2022 |volume=184 |pages=430–442 |doi=10.1016/j.renene.2021.11.067 |bibcode=2022REne..184..430J |s2cid=244820608 |language=en |issn=0960-1481 |url=https://www.sciencedirect.com/science/article/abs/pii/S0960148121016499 |url-access=subscription}}{{cite journal |last1=Gielen |first1=Dolf |last2=Boshell |first2=Francisco |last3=Saygin |first3=Deger |last4=Bazilian |first4=Morgan D. |last5=Wagner |first5=Nicholas |last6=Gorini |first6=Ricardo |title=The role of renewable energy in the global energy transformation |journal=Energy Strategy Reviews |date=1 April 2019 |volume=24 |pages=38–50 |doi=10.1016/j.esr.2019.01.006 |bibcode=2019EneSR..24...38G |s2cid=135283552 |language=en |issn=2211-467X}}

File:Thermal-oxidizer-rto.jpgs are air pollution abatement options for hazardous air pollutants (HAPs), volatile organic compounFds (VOCs), and odorous emissions.|alt=a smokestack attached to a metal box]]

Various pollution control technologies and strategies are available to reduce air pollution. For instance, industrial plants can install scrubbers, such as flue gas desulfurization or catalysts to remove NO_x.{{Cite journal |last1=Amann |first1=Markus |last2=Kiesewetter |first2=Gregor |last3=Schöpp |first3=Wolfgang |last4=Klimont |first4=Zbigniew |last5=Winiwarter |first5=Wilfried |last6=Cofala |first6=Janusz |last7=Rafaj |first7=Peter |last8=Höglund-Isaksson |first8=Lena |last9=Gomez-Sabriana |first9=Adriana |last10=Heyes |first10=Chris |last11=Purohit |first11=Pallav |last12=Borken-Kleefeld |first12=Jens |last13=Wagner |first13=Fabian |last14=Sander |first14=Robert |last15=Fagerli |first15=Hilde |date=2020-09-28 |title=Reducing global air pollution: the scope for further policy interventions |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |volume=378 |issue=2183 |page=20190331 |doi=10.1098/rsta.2019.0331 |pmc=7536039 |pmid=32981437|bibcode=2020RSPTA.37890331A }} Stringent environmental regulations, effective control technologies and shift towards the renewable source of energy also helping countries like China and India to reduce their sulfur dioxide pollution.{{Cite journal |last1=Kuttippurath |first1=J. |last2=Patel |first2=V. K. |last3=Pathak |first3=M. |last4=Singh |first4=A. |date=2022 |title=Improvements in SO2 pollution in India: role of technology and environmental regulations|journal=Environmental Science and Pollution Research |language=en |volume=29 |issue=52 |pages=78637–78649 |doi=10.1007/s11356-022-21319-2 |pmid=35696063 |pmc=9189448 |bibcode=2022ESPR...2978637K |s2cid=249613744 |issn=1614-7499}}

In the power sector, a very effective means to reduce air pollution is the transition to renewable energy or nuclear power.

A growing number of countries regulates waste, which include national or city-wide waste management systems, opening managed landfills, landfill gas capture (for electricity production), and waste separation. In agriculture, air pollution can be minimised by not overusing fertilisers and by not feeding excess protein to livestock.

{{Further|Sustainable transport}}

File:Electric Rickshaws.jpg in Nepal|alt=a row of electric rickshaws with a couple of people inside]]

File:Alicante Tram 5.jpg, Spain|alt=see caption]]

The avoid-shift-improve framework groups efforts to cut pollution from vehicles into reducing travel, shifting to sustainable transport, and improving vehicle technology.{{Cite journal |last1=Leroutier |first1=Marion |last2=Quirion |first2=Philippe |date=2023-11-01 |title=Tackling Car Emissions in Urban Areas: Shift, Avoid, Improve |url=https://linkinghub.elsevier.com/retrieve/pii/S0921800923002148 |journal=Ecological Economics |volume=213 |page=107951 |doi=10.1016/j.ecolecon.2023.107951 |bibcode=2023EcoEc.21307951L |issn=0921-8009}} Reducing motor vehicle travel can curb pollution. One strategy is to build compact cities, so that amenities are close by and cars are not needed.{{cite book |last1=Ringenson |first1=Tina |chapter=Mobility as a Service and the Avoid-Shift-Improve Approach |date=2021 |title=Progress in IS |page=218 |location=Cham |publisher=Springer International |isbn=978-3-030-88062-0 |last2=Kramers |first2=Anna|doi=10.1007/978-3-030-88063-7_14 }} Motor traffic can be reduced by creating more walkable cities and by investing in cycling infrastructure.{{Cite web |title=Blue skies and healthy lives: How active travel is transforming our cities |url=https://www.c40.org/news/how-active-travel-is-transforming-cities/ |access-date=2025-01-10 |website=C40 Cities |language=en-GB}} Working from home is another way of avoiding motorised traffic.

Traffic can be shifted to cleaner modes of transport, for instance by increased use of public transport.{{cite journal |last1=Landrigan |first1=Philip J. |date=1 January 2017 |title=Air pollution and health |journal=The Lancet Public Health |language=English |volume=2 |issue=1 |pages=e4–e5 |doi=10.1016/S2468-2667(16)30023-8 |issn=2468-2667 |pmid=29249479}} For instance, by increasing the cost of car parking or offering free public transport. Tackling congestion, which increases fuel usage, with congestion charging, also shifts people to use cleaner modes of transport. Finally, road vehicles can be improved from increased fuel efficiency, improved quality of fuels, emission standards, and conversion to electric vehicles.{{Cite journal |last1=Jonidi Jafari |first1=Ahmad |last2=Charkhloo |first2=Esmail |last3=Pasalari |first3=Hasan |date=2021-12-01 |title=Urban air pollution control policies and strategies: a systematic review |url=https://doi.org/10.1007/s40201-021-00744-4 |journal=Journal of Environmental Health Science and Engineering |language=en |volume=19 |issue=2 |pages=1911–1940 |doi=10.1007/s40201-021-00744-4 |issn=2052-336X |pmc=8617239 |pmid=34900316|bibcode=2021JEHSE..19.1911J }} For example, buses in New Delhi, India, switched to compressed natural gas after 2000, to help eliminate the city's "pea-soup" smog.{{Cite journal |last1=Krelling |first1=Christian |last2=Badami |first2=Madhav G. |date=2022-01-01 |title=Cost-effectiveness analysis of compressed natural gas implementation in the public bus transit fleet in Delhi, India |url=https://www.sciencedirect.com/science/article/abs/pii/S0967070X21002973 |journal=Transport Policy |volume=115 |pages=49–61 |doi=10.1016/j.tranpol.2021.10.019 |issn=0967-070X}}

File:Solar_Cooker_Phuktar_Gompa_Zanskar_Oct22_A7C_04476.jpg at the Phugtal Monastery in Ladakh, India|alt=a parabolic mirror concentrates heat into a placeholder for kettles and pans.]]

Various technologies are available for clean cooking, to replace traditional biomass stoves or three-stone fires. For instance, a switch to cooking with biogas, bioethanol, electricity, natural gas or LPG (liquified petroleum gas), significantly reduces air pollution. Improved cookstoves, which use biomass more efficiently, improve air quality less, but can be an intermediate solution if clean cookstoves or their fuels are not available. These clean cooking devices, including those run on fossil fuels, usually have a smaller climate impact than traditional biomass stoves.{{cite book|author=International Energy Agency, African Development Bank Group|title = A Vision for Clean Cooking Access for All|date=2023|url=https://iea.blob.core.windows.net/assets/f63eebbc-a3df-4542-b2fb-364dd66a2199/AVisionforCleanCookingAccessforAll.pdf|pages=19, 21}}

Kerosine for lighting can be replaced with efficient LED lights, for instance solar-powered LED lights.{{Cite book |url=https://www.who.int/publications/i/item/9789241565233 |title=Burning opportunity: clean household energy for health, sustainable development, and wellbeing of women and children |publisher=World Health Organization |year=2016 |location=Geneva, Switzerland |page=52 |archive-url=https://web.archive.org/web/20171124101534/http://www.who.int/airpollution/publications/burning-opportunities/en/ |archive-date=November 24, 2017 |url-status=live}} Combustion of fossil fuels for space heating can be replaced by the use of electricity in heat pumps.{{Cite web |date=2024-11-13 |title=Air pollution from heating and cooling: stepping up clean energy use urgently needed - European Commission |url=https://joint-research-centre.ec.europa.eu/jrc-news-and-updates/air-pollution-heating-and-cooling-stepping-clean-energy-use-urgently-needed-2025-01-07_en |access-date=2025-01-10 |website=joint-research-centre.ec.europa.eu |language=en}}

{{Main|Air quality law|Emission standard}}

File:"When the smoke came", air pollution in Shanghai.jpg" in 2014, which drastically lowered particle pollution levels across the country.{{Cite web |title=AQLI Policy Impacts—China: National Air Quality Action Plan (2014) |url=https://aqli.epic.uchicago.edu/policy-impacts/china-national-air-quality-action-plan-2014/ |access-date=2025-05-24 |website=AQLI |language=en}}]]

Although a majority of countries have air pollution laws, 43% of countries lack a legal definition of air pollution, 34% lack outdoor air quality standards, and just 31% have laws for tackling pollution originating from outside their borders. Few countries have limits that are as strict as the World Health Organization's recommendations.{{cite book |url=https://www.unep.org/resources/report/regulating-air-quality-first-global-assessment-air-pollution-legislation |title=Regulating Air Quality: The First Global Assessment of Air Pollution Legislation |date=2021 |publisher=United Nations Environment Programme |isbn=978-92-807-3872-8 |location=Nairobi, Kenya |pages=7, 41, 46, 56 |access-date=10 April 2024}}

Some air pollution laws include specific air quality standards, such as the U.S. National Ambient Air Quality Standards and E.U. Air Quality Directive,{{Cite web |url=http://ec.europa.eu/environment/air/quality/legislation/directive.htm |archive-url=https://web.archive.org/web/20110511090225/http://ec.europa.eu/environment/air/quality/legislation/directive.htm |archive-date=2011-05-11 |title=European Commission - Environment - Air - Air quality |date=11 May 2011 |author=European Commission}} which specify maximum atmospheric concentrations for specific pollutants. Other examples of air quality laws around the world include the Clean Air Act in Britain, the US Clean Air Act, and TA Luft in Germany.{{Cite web |title=German TA-Luft is guaranteed by us |url=https://www.centrotherm-cs.de/en/innovation/news-journal/detail/?cHash=2f8c3c73736a8bfee683c94544e0d805&tx_news_pi1%5Baction%5D=detail&tx_news_pi1%5Bcontroller%5D=News&tx_news_pi1%5Bnews%5D=9 |access-date=2022-02-27 |website=centrotherm clean solutions |language=en-US |archive-date=29 June 2022 |archive-url=https://web.archive.org/web/20220629162917/https://www.centrotherm-cs.de/en/innovation/news-journal/detail/?cHash=2f8c3c73736a8bfee683c94544e0d805&tx_news_pi1%5Baction%5D=detail&tx_news_pi1%5Bcontroller%5D=News&tx_news_pi1%5Bnews%5D=9 }} Some air pollution laws put limits on emissions (e.g. from vehicles), as well as air standards.{{cite book |url=https://www.unep.org/resources/report/regulating-air-quality-first-global-assessment-air-pollution-legislation |title=Regulating Air Quality: The First Global Assessment of Air Pollution Legislation |date=2021 |publisher=United Nations Environment Programme |isbn=978-92-807-3872-8 |location=Nairobi, Kenya |page=42 |access-date=10 April 2024}}

Some air pollution action has been successful at the international level, such as the Montreal Protocol, which reduced the release of harmful ozone-depleting chemicals. It was ratified worldwide. On the other hand, international action on climate change, have been less successful, as levels of greenhouses gases have continued to rise since the 1997 Kyoto Protocol and the 2015 Paris Agreement.

The World Health Organization's Global Air Quality Guidelines encourage improvements in a similar way to national standards, but are "recommendations" and "good practice" rather than mandatory targets that countries must achieve.{{cite web |title=WHO Global Air Quality Guidelines |url=https://www.who.int/news-room/questions-and-answers/item/who-global-air-quality-guidelines |website=World Health Organization |access-date=17 January 2025}}

In 2022, the UN General Assembly passed a resolution recognizing the right to a clean, healthy, and sustainable environment as a human right. The resolution is not legally binding. This resolution followed the declaration from the UN Human Rights Council, earlier that year.{{Cite web |date=2022-07-28 |title=In historic move, UN declares healthy environment a human right |url=https://www.unep.org/news-and-stories/story/historic-move-un-declares-healthy-environment-human-right |access-date=2025-02-12 |website=www.unep.org |language=en}}

While many countries have air pollution laws, they differ in how they can be enforced via litigation. In the European Union, individual countries, including France, have been fined by the EU for not complying with air quality rules. The revised Ambient Air Quality Directive also makes it possible for individuals in the EU to seek compensation.{{Cite web |date=2020-10-30 |title=Air quality: Commission decides to refer France to the Court over failure to meet its obligation to protect citizens against poor air quality |url=https://ec.europa.eu/commission/presscorner/detail/en/ip_20_1880 |access-date=2025-02-12 |website=European Commission}} While China allows litigation on environmental grounds, it is rare as it is seen as risky.{{Cite web |last=Kurushina |first=Daria |date=2024-07-09 |title=Climate litigation can power China's low-carbon transition |url=https://dialogue.earth/en/justice/climate-litigation-can-power-chinas-low-carbon-transition/ |access-date=2025-05-24 |website=Dialogue Earth |language=en}} In Chile, the right to a healthy environment is part of the constitution, and the Supreme Court found that the government has to act to provide clear air because of this.{{Cite journal |last1=Tigre |first1=Maria Antonia |last2=Urzola |first2=Natalia |last3=Goodman |first3=Alexandra |date=2023-04-01 |title=Climate litigation in Latin America: is the region quietly leading a revolution? |url=https://www.elgaronline.com/view/journals/jhre/14/1/article-p67.xml?tab_body=pdf |journal=Journal of Human Rights and the Environment |language=en |volume=14 |issue=1 |pages=67–93 |doi=10.4337/jhre.2023.01.04 |bibcode=2023JHRE...14...67T |issn=1759-7188}}

{{Portal|Global warming|Plants|Trees}}

{{Div col|small=yes}}

• Air stagnation
• Atmospheric chemistry
• Global Atmosphere Watch
• Global dimming
• List of smogs by death toll

{{Div col end}}

{{Reflist}}

{{Library resources box |by=no |onlinebooks=no |others=yes lcheading=Air – Pollution}}

• {{cite book |last1=Cherni |first1=Judith |title=Economic Growth Versus the Environment: The Politics of Wealth, Health and Air Pollution |date=2002 |publisher=Palgrave |location=New York |isbn=0-333-92956-X |url=https://archive.org/details/economicgrowthve0000cher|access-date=8 January 2025}}
• {{cite book |last1=Corton |first1=Christine |title=London Fog: The Biography |date=2015 |publisher=Harvard University Press |isbn=978-0-674-08835-1 |url=https://books.google.com/books?id=uipUCwAAQBAJ |access-date=8 January 2025}}
• {{cite journal |last1=Fowler |first1=David|author1-link=David Fowler (physicist) |last2=Brimblecombe |first2=Peter |last3=Burrows |first3=John |last4=Heal |first4=Mathew |last5=Grennfelt |first5=Peringe |last6=Stevenson|first6=David|first7=Alan|last7=Jowett|first8=Eiko|last8=Nemitz|first9=Mhairi|last9=Coyle|first10=Xuejun|last10=Liu|first11=Yunhua|last11=Chang|first12=Gary|last12=Fuller|first13=Mark|last13=Sutton|first14=Zbigniew|last14=Klimont|first15=Mike|last15=Unsworth|first16=Massimo|last16=Vieno|title=A chronology of global air quality |journal=Phil. Trans. R. Soc. A |date=30 October 2020 |volume=378 |issue=2183 |doi=10.1098/rsta.2019.0314 |pmid=32981430|pmc=7536029 |bibcode=2020RSPTA.37890314F }}
• {{cite book |last1=Gonzalez |first1=George |title=The Politics of Air Pollution: Urban Growth, Ecological Modernization, and Symbolic Inclusion |date=2012 |publisher=State University of New York Press |location=New York |isbn=978-0-7914-8386-2 |url=https://books.google.com/books?id=ofxc2dMtEBAC |access-date=8 January 2025}}
• {{cite book |last1=Hill |first1=Marquita |title=Understanding Environmental Pollution |date=2020 |publisher=Cambridge University Press |location=Cambridge, UK |isbn=978-1-108-43610-6 |edition=Fourth |url=https://books.google.com/books?id=hILoDwAAQBAJ |access-date=4 February 2025}}
• {{cite book | first1 = Chris |last1=Woodford|author1-link=Chris Woodford (author) | date = 2021 | title = Breathless: Why Air Pollution Matters – and How it Affects You | publisher = Icon Books | pages = | isbn = 978-1-78578-710-2 | url = https://books.google.com/books?id=0lEXEAAAQBAJ|access-date=8 January 2025}}

{{Commons}}

{{Wikivoyage|3=travel information}}

• [https://www.who.int/data/gho/data/themes/air-pollution/who-air-quality-database WHO Ambient Air quality database]
• [http://aqicn.org/map/world/ Global real-time air quality index map]
• [https://www.airnow.gov/aqi/ Air Quality Index (AQI) Basics and Calculator]
• [https://ec.europa.eu/environment/air/quality/index.htm European Commission > Environment > Air > Air Quality]
• [https://www.epa.gov/haps/ Hazardous air pollutants] at EPA.gov

{{Pollution}}

{{World topic|prefix=Air pollution in|title=Air pollution in the world|noredlinks=yes}}

{{Asia Pollution|state=collapsed}}

{{Environmental science}}

{{Public health}}

{{Natural resources}}

{{Authority control}}

{{DEFAULTSORT:Air Pollution}}

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