Smog
Part of a series on |
Pollution |
---|
External audio | |
---|---|
"Fighting Smog in Los Angeles", Distillations Podcast, 2018 Science History Institute |
Smog, or smoke fog, is a type of intense
Smog is often categorized as being either
Photochemical smog, as found for example in Los Angeles, is a type of air pollution derived from
Etymology
Coinage of the term "smog" has been attributed to Henry Antoine Des Voeux in his 1905 paper, "Fog and Smoke" for a meeting of the Public Health Congress. The 26 July 1905 edition of the London newspaper Daily Graphic quoted Des Voeux, "He said it required no science to see that there was something produced in great cities which was not found in the country, and that was smoky fog, or what was known as 'smog'."[3]: 1 [dead link] The following day the newspaper stated that "Dr. Des Voeux did a public service in coining a new word for the London fog."
However, the term appeared twenty-five years earlier than Voeux's paper, in the Santa Cruz & Monterey Illustrated Handbook published in 1880[4] and also appears in print in a column quoting from the book in the 3 July 1880, Santa Cruz Weekly Sentinel.[5] On 17 December 1881, in the publication Sporting Times, the author claims to have invented the word: "The 'Smog' – a word I have invented, combined of smoke and fog, to designate the London atmosphere..."[6]
Anthropogenic causes
Coal
Coal fire can emit significant clouds of smoke that contribute to the formation of winter smog. Coal fires can be used to heat individual buildings or to provide energy in a power-producing plant. Air pollution from this source has been reported in England since the
Transportation emissions
Traffic emissions – such as from
The major culprits from transportation sources are
Photochemical smog
Photochemical smog, often referred to as "summer smog", is the chemical reaction of sunlight,
The composition and chemical reactions involved in photochemical smog were not understood until the 1950s. In 1948, flavor chemist Arie Haagen-Smit adapted some of his equipment to collect chemicals from polluted air, and identified ozone as a component of Los Angeles smog. Haagen-Smit went on to discover that nitrogen oxides from automotive exhausts and gaseous hydrocarbons from cars and oil refineries, exposed to sunlight, were key ingredients in the formation of ozone and photochemical smog.[25]: 219–224 [26][27] Haagen-Smit worked with Arnold Beckman, who developed various equipment for detecting smog, ranging from an "Apparatus for recording gas concentrations in the atmosphere" patented on 7 October 1952, to "air quality monitoring vans" for use by government and industry.[25]: 224–226
Formation and reactions
During the morning rush hour, a high concentration of nitric oxide and hydrocarbons are emitted to the atmosphere, mostly via on-road traffic but also from industrial sources. Some hydrocarbons are rapidly oxidized by OH· and form peroxy radicals, which convert nitric oxide (NO) to nitrogen dioxide (NO2).
(1)
(2)
(3)
Nitrogen dioxide (NO2) and nitric oxide (NO) further react with ozone (O3) in a series of chemical reactions:
(4) ,
(5)
(6)
This series of equations is referred to as the photostationary state (PSS). However, because of the presence of Reaction 2 and 3, NOx and ozone are not in a perfectly steady state. By replacing Reaction 6 with Reaction 2 and Reaction 3, the O3 molecule is no longer destroyed. Therefore, the concentration of ozone keeps increasing throughout the day. This mechanism can escalate the formation of ozone in smog. Other reactions such as the photooxidation of formaldehyde (HCHO), a common secondary pollutant, can also contribute to the increased concentration of ozone and NO2. Photochemical smog is more prevalent during summer days since incident solar radiation fluxes are high, which favors the formation of ozone (reactions 4 and 5). The presence of a temperature inversion layer is another important factor. That is because it prevents the vertical convective mixing of the air and thus allows the pollutants, including ozone, to accumulate near the ground level, which again favors the formation of photochemical smog.
There are certain reactions that can limit the formation of O3 in smog. The main limiting reaction in polluted areas is:
(7)
This reaction removes NO2 which limits the amount of O3 that can be produced from its photolysis (reaction 4). HNO3 is a sticky compound that can easily be removed onto surfaces (dry deposition) or dissolved in water and be rained out (wet deposition). Both ways are common in the atmosphere and can efficiently remove radicals and nitrogen dioxide.
Natural causes
Volcanoes
An erupting volcano can emit high levels of sulfur dioxide along with a large quantity of particulates matter; two key components to the creation of smog. However, the smog created as a result of a volcanic eruption is often known as vog to distinguish it as a natural occurrence. The chemical reactions that form smog following a volcanic eruption are different than the reactions that form photochemical smog. The term smog encompasses the effect when a large number of gas-phase molecules and particulate matter are emitted to the atmosphere, creating a visible haze. The event causing a large number of emissions can vary but still result in the formation of smog.
Plants
Plants are another natural source of hydrocarbons that could undergo reactions in the atmosphere and produce smog. Globally both plants and soil contribute a substantial amount to the production of hydrocarbons, mainly by producing isoprene and terpenes.[28] Hydrocarbons released by plants can often be more reactive than man-made hydrocarbons. For example when plants release isoprene, the isoprene reacts very quickly in the atmosphere with hydroxyl radicals. These reactions produce hydroperoxides which increase ozone formation.[29]
Health effects
Smog is a serious problem in many cities and continues to harm human health.
There is a lack of knowledge on the long-term effects of air pollution exposure and the origin of asthma. An experiment was carried out using intense air pollution similar to that of the 1952 Great Smog of London. The results from this experiment concluded that there is a link between early-life pollution exposure that leads to the development of asthma, proposing the ongoing effect of the Great Smog.[35] Modern studies continue to find links between mortality and the presence of smog. One study, published in
Levels of unhealthy exposure
The
Premature deaths due to cancer and respiratory disease
In 2016, the Ontario Medical Association announced that smog is responsible for an estimated 9,500 premature deaths in the province each year.[39]
A 20-year American Cancer Society study found that cumulative exposure also increases the likelihood of premature death from respiratory disease, implying the 8-hour standard may be insufficient.[40]
Alzheimer risk
Tiny magnetic particles from air pollution have for the first time been discovered to be lodged in human brains– and researchers think they could be a possible cause of Alzheimer's disease. Researchers at Lancaster University found abundant magnetite nanoparticles in the brain tissue from 37 individuals aged three to 92-years-old who lived in Mexico City and Manchester. This strongly magnetic mineral is toxic and has been implicated in the production of reactive oxygen species (free radicals) in the human brain, which is associated with neurodegenerative diseases including Alzheimer's disease.[41][42]
Risk of certain birth defects
A study examining 806 women who had babies with birth defects between 1997 and 2006, and 849 women who had healthy babies, found that smog in the
Low birth weight
According to a study published in
Other negative effects
Although severe health effects caused by smog are the chief issue, intense air pollution caused by haze from air pollution, dust storm particles, and bush fire smoke, cause a reduction in irradiance that hurts both solar photovoltaic[46] production as well as agricultural yield.[47]
Areas affected
Smog can form in almost any climate where industries or cities release large amounts of air pollution, such as smoke or gases. However, it is worse during periods of warmer, sunnier weather when the upper air is warm enough to inhibit vertical circulation. It is especially prevalent in geologic basins encircled by hills or mountains. It often stays for an extended period of time over densely populated cities or urban areas and can build up to dangerous levels.
Canada
According to the Canadian Science Smog Assessment published in 2012, smog is responsible for detrimental effects on human and ecosystem health, as well as socioeconomic well-being across the country. It was estimated that the province of Ontario sustains $201 million in damages annually for selected crops, and an estimated tourism revenue degradation of $7.5 million in Vancouver and $1.32 million in The Fraser Valley due to decreased visibility. Air pollution in British Columbia is of particular concern, especially in the Fraser Valley, because of a meteorological effect called inversion which decreases air dispersion and leads to smog concentration.[48]
Delhi, India
For the past few years, cities in northern
Delhi is the most polluted
Environmentalists have criticized the Delhi government for not doing enough to curb air pollution and to inform people about air quality issues.[55] Most of Delhi's residents are unaware of alarming levels of air pollution in the city and the health risks associated with it.[58] Since the mid-1990s, Delhi has undertaken some measures to curb air pollution – Delhi has the third highest quantity of trees among Indian cities[65] and the Delhi Transport Corporation operates the world's largest fleet of environmentally friendly compressed natural gas (CNG) buses.[66] In 1996, the Centre for Science and Environment (CSE) started a public interest litigation in the Supreme Court of India that ordered the conversion of Delhi's fleet of buses and taxis to run on CNG and banned the use of leaded petrol in 1998. In 2003, Delhi won the United States Department of Energy's first 'Clean Cities International Partner of the Year' award for its "bold efforts to curb air pollution and support alternative fuel initiatives".[66] The Delhi Metro has also been credited for significantly reducing air pollutants in the city.[67]
However, according to several authors, most of these gains have been lost, especially due to stubble burning, rise in market share of diesel cars and a considerable decline in bus ridership.[68][69] According to CUE and System of Air Quality Weather Forecasting and Research (SAFER), burning of agricultural waste in nearby Punjab, Haryana and Uttar Pradesh regions results in severe intensification of smog over Delhi.[70][71] The state government of adjoining Uttar Pradesh is considering imposing a ban on crop burning to reduce pollution in Delhi NCR and an environmental panel has appealed to India's Supreme Court to impose a 30% cess on diesel cars.[72][73]
Beijing, China
Joint research between American and Chinese researchers in 2006 concluded that much of the city's pollution comes from surrounding cities and provinces. On average 35–60% of the ozone can be traced to sources outside the city. Shandong Province and Tianjin Municipality have a "significant influence on Beijing's air quality",[74] partly due to the prevailing south/southeasterly flow during the summer and the mountains to the north and northwest.
United Kingdom
London
In 1306, concerns over air pollution were sufficient for Edward I to (briefly) ban coal fires in London.[7] In 1661, John Evelyn's Fumifugium suggested burning fragrant wood instead of mineral coal, which he believed would reduce coughing. The "Ballad of Gresham College" the same year describes how the smoke "does our lungs and spirits choke, Our hanging spoil, and rust our iron."
Severe episodes of smog continued in the 19th and 20th centuries, mainly in the winter, and were nicknamed "pea-soupers," from the phrase "as thick as pea soup". The
In 1956 the
It was after this that the great clean-up of London began. One by one, historical buildings which, during the previous two centuries had gradually completely blackened externally, had their stone facades cleaned and restored to their original appearance. Victorian buildings whose appearance changed dramatically after cleaning included the
Other areas
Other areas of the United Kingdom were affected by smog, especially heavily industrialised areas.
The cities of Glasgow and Edinburgh, in Scotland, suffered smoke-laden fogs in 1909. Des Voeux, commonly credited with creating the "smog" moniker, presented a paper in 1911 to the Manchester Conference of the Smoke Abatement League of Great Britain about the fogs and resulting deaths.[78]
One Birmingham resident described near black-out conditions in the 1900s before the Clean Air Act, with visibility so poor that cyclists had to dismount and walk in order to stay on the road.[79]
On 29 April 2015, the
Mexico City, Mexico
Due to its location in a highland "bowl", cold air sinks down onto the urban area of Mexico City, trapping industrial and vehicle pollution underneath, and turning it into the most infamously smog-plagued city of Latin America. Within one generation, the city has changed from being known for some of the cleanest air of the world into one with some of the worst pollution, with pollutants like nitrogen dioxide being double or even triple international standards.[82]
Santiago, Chile
Similar to Mexico City, the air pollution of Santiago valley, located between the Andes and the Chilean Coast Range, turn it into the most infamously smog-plagued city of South America. Other aggravates of the situation reside in its high latitude (31 degrees South) and dry weather during most of the year.
Tehran, Iran
In December 2005, schools and public offices had to close in Tehran and 1,600 people were taken to hospital, in a severe smog blamed largely on unfiltered car exhaust.[83]
United States
Smog was brought to the attention of the general U.S. public in 1933 with the publication of the book "Stop That Smoke", by Henry Obermeyer, a New York public utility official, in which he pointed out the effect on human life and even the destruction of 3,000 acres (12 km2) of a farmer's spinach crop.[84] Since then, the United States Environmental Protection Agency has designated over 300 U.S. counties to be non-attainment areas for one or more pollutants tracked as part of the National Ambient Air Quality Standards.[85] These areas are largely clustered around large metropolitan areas, with the largest contiguous non-attainment zones in California and the Northeast. Various U.S. and Canadian government agencies collaborate to produce real-time air quality maps and forecasts.[86] To combat smog conditions, localities may declare "smog alert" days, such as in the Spare the Air program in the San Francisco Bay Area. By 1970, Congress enacted the Clean Air Act to regulate air pollutant emissions.[87]
In the United States, smog pollution kills 24,000 Americans every year. The U.S. is among the dirtier countries in terms of smog, ranked 123 out of 195 countries measured, where 1 is cleanest and 195 is most smog polluted.[88]
Los Angeles and the San Joaquin Valley
Because of their locations in low basins surrounded by mountains, Los Angeles and the San Joaquin Valley are notorious for their smog. Heavy automobile traffic, combined with the additional effects of the San Francisco Bay and Los Angeles/Long Beach port complexes, frequently contribute to further air pollution.
Los Angeles, in particular, is strongly predisposed to the accumulation of smog, because of the peculiarities of its geography and weather patterns. Los Angeles is situated in a flat basin with the ocean on one side and mountain ranges on three sides. A nearby cold ocean current depresses surface air temperatures in the area, resulting in an
Los Angeles was one of the best-known cities suffering from transportation smog for much of the 20th century, so much so that it was sometimes said that Los Angeles was a synonym for smog.[89] In 1970, when the Clean Air Act was passed, Los Angeles was the most polluted basin in the country, and California was unable to create a State Implementation Plan that would enable it to meet the new air quality standards.[90] However, ensuing strict regulations by state and federal government agencies overseeing this problem (such as the California Air Resources Board and the United States Environmental Protection Agency), including tight restrictions on allowed emissions levels for all new cars sold in California and mandatory regular emission tests of older vehicles, resulted in significant improvements in air quality.[91] For example, air concentrations of volatile organic compounds declined by a factor of 50 between 1962 and 2012.[92] Concentrations of air pollutants such as nitrous oxides and ozone declined by 70% to 80% over the same period of time.[93]
Major incidents in the U.S.
- 26 July 1943,
- 30-31 October 1948, Donora, Pennsylvania: 20 died, 600 hospitalized, thousands more stricken. Lawsuits were not settled until 1951.[96]
- New York City, New York: Smog kills at least 169[97]people.
Ulaanbaatar, Mongolia
In the late 1990s, massive immigration to Ulaanbaatar from the countryside began. An estimated 150,000 households, mainly living in traditional Mongolian gers on the outskirts of Ulaanbaatar, burn wood and coal (some poor families burn even car tires and trash) to heat themselves during the harsh winter, which lasts from October to April, since these outskirts are not connected to the city's central heating system. A temporary solution to decrease smog was proposed in the form of stoves with improved efficiency, although with no visible results. Coal-fired ger stoves release high levels of ash and other particulate matter (PM). When inhaled, these particles can settle in the lungs and respiratory tract and cause health problems. At two to 10 times above Mongolian and international air quality standards, Ulaanbaatar's PM rates are among the worst in the world, according to a December 2009 World Bank report. The Asian Development Bank (ADB) estimates that health costs related to this air pollution account for as much as 4 percent of Mongolia's GDP.[98]
Southeast Asia
Smog is a regular problem in
The
Pakistan
Since the start of the winter season, heavy smog loaded with pollutants covered major parts of Punjab, especially the city of Lahore,[106] causing breathing problems and disrupting normal traffic.[107] A recent study from 2022 shows that the primary cause of pollution in Lahore is from traffic-related PM (both exhausts and non exhaust sources)[108]
Doctors advised residents to stay indoors and wear facemasks outside.[109]
Pollution index
The severity of smog is often measured using automated optical instruments such as nephelometers, as haze is associated with visibility and traffic control in ports. Haze, however, can also be an indication of poor air quality, though this is often better reflected using accurate purpose-built air indexes such as the American Air Quality Index, the Malaysian API (Air Pollution Index), and the Singaporean Pollutant Standards Index.
In hazy conditions, it is likely that the index will report the suspended particulate level. The disclosure of the responsible pollutant is mandated in some jurisdictions.
The Malaysian API does not have a capped value. Hence, its most hazardous readings can go above 500. When the reading goes above 500, a state of emergency is declared in the affected area. Usually, this means that non-essential government services are suspended, and all ports in the affected area are closed. There may also be prohibitions on private sector commercial and industrial activities in the affected area excluding the food sector. So far, the state of emergency rulings due to hazardous API levels was applied to the Malaysian towns of Port Klang, Kuala Selangor, and the state of Sarawak during 1997 Southeast Asian haze and the 2005 Malaysian haze.[needs update]
Cultural references
- The London "T.S. Eliot's "The Love Song of J. Alfred Prufrock".
- In the 1957 What's Opera, Doc, Elmer Fudd called for various calamities to befall Bugs Bunny, ending in a screamed "SMOG!!"
- The 1970 made-for-TV movie A Clear and Present Danger was one of the first American television network entertainment programs to warn about the problem of smog and air pollution, as it dramatized a man's efforts toward clean air after emphysema killed his friend.[110]
- The history of smog in LA is detailed in Smogtown by Chip Jacobs and William J. Kelly.[111]
See also
- Smog tower
- Asian brown cloud
- 1997 Southeast Asian haze
- 2005 Malaysian haze
- 2006 Southeast Asian haze
- 2013 Eastern China smog
- 2013 Northeastern China smog
- 2013 Southeast Asian haze
- 2015 Southeast Asian haze
- Atmospheric chemistry
- CityTrees
- Contrail
- Criteria air contaminants
- Emission standard
- Great Smog of London
- Haze
- Inversion (meteorology)
- List of least polluted cities by particulate matter concentration
- Nitric oxide
- Ozone
- Umweltzone
- Vog
References
- ISBN 978-5-7057-5026-9.)
{{cite book}}
: CS1 maint: multiple names: authors list (link - ISBN 978-0-19-504605-2.[page needed]
- ^ Piazzesi, Gaia (2006). The Catalytic Hydrolysis of Isocyanic Acid (HNCO) in the Urea-SCR Process (PDF) (PhD Thesis). ETH Zurich. Archived from the original (PDF) on 1 December 2017. Retrieved 25 October 2013.
- ^ Meyrick, Henry (1880). Santa Cruz & Monterey Illustrated Handbook. San Francisco News Publishing Co. pp. 7–8.
It is really not fog at all, but cloud of pure white mist, warmer and much less wetting than a "Scotch mist," and differing entirely from the true British fog, facetiously spelled "smog," because always colored and strongly impregnated with smoke, a mixture as unwholesome as it is unpleasant.
- ^ "The morning fog". Santa Cruz Weekly Sentinel. 3 July 1880. p. 3. Retrieved 18 September 2019.
It is really not fog at all, but cloud of pure white mist. warmer and much less wetting than a "Scotch Mist," not differing entirely from the true British fog, facetiously spelled "smog" because always colored and strongly impregnated with smoke, a mixture as unwholesome as it is unpleasant.
- ^ Playhouses without Plays, Sporting Times, London, December 17, 1881, p6. Accessed September 12, 2020, The British Newspaper Archive.
- ^ a b Chris (2007). "Environmentalism in 1306". By Environmental Graffiti. Archived from the original on 25 July 2008.
- ^ Karl (2008). "Environmentalism in 1306". By Environmental Graffiti.
- ^ Heilmann, Sebastian, ed. (2017). China's Political System. Rowman & Littlefield. p. 360. Archived from the original on 11 October 2016.
- ^ "Clearing the Air". The Surface Transportation Policy Project. 19 August 2003. Archived from the original on 8 February 2007. Retrieved 26 April 2007.
- ^ "EPA Tools Available as Summer Smog Season Starts" (Press release). Boston, Massachusetts: United States Environmental Protection Agency. 30 April 2008.
- ^ "Sprawl Report 2001: Measuring Vehicle Contribution to Smog". Sierra Club. 2001. Archived from the original on 15 November 2001. Retrieved 25 October 2013.
- ^ "Smog – Causes". The Environment: A Global Challenge. Archived from the original on 19 January 2001. Retrieved 25 October 2013.
- ^ a b c Smog — Who Does It Hurt? What You Need to Know About Ozone and Your Health (EPA-452/K-99-001) (PDF) (Report). United States Environmental Protection Agency. July 1999. Archived from the original (PDF) on 28 March 2008.
- ^ "State and County Emission Summaries: Carbon Monoxide". Air Emission Sources. United States Environmental Protection Agency. 25 October 2013.
- ^ a b c d "Motor vehicle pollution". Queensland Government. 4 April 2013.
- ^ a b c "Health". Nitrogen Dioxide. United States Environmental Protection Agency. 14 February 2013.
- ^ "The Regional Transport of Ozone: New EPA Rulemaking on Nitrogen Oxide Emissions (EPA-456/F-98-006)" (PDF). United States Environmental Protection Agency. September 1998.
- ^ "State and County Emission Summaries: Nitrogen Oxides". Air emission sources. United States Environmental Protection Agency. 25 October 2013.
- ^ "ESS Topic Smog". Amazing World of Science With Mr. Green. Retrieved 19 September 2019.
- ^ "Nox/VOC Smog Fact Sheet" (PDF). Canadian Council of Ministers of the Environment. Archived from the original (PDF) on 28 September 2011.
{{cite journal}}
: Cite journal requires|journal=
(help) - ^ "Smog: Photochemical smog & Sulfurous smog". 4 January 2016.
- ^ "Educate about Smog: What causes acid rain?". www.englishnotes4all.com. Archived from the original on 2 November 2018. Retrieved 5 November 2018.
- ISBN 978-0-534-37697-0.
- ^ ISBN 978-0-941901-23-9.
- ^ Gardner, Sarah (14 July 2018). "Smog: the battle against air pollution". Marketplace.org. American Public Media. Archived from the original on 24 January 2018. Retrieved 6 November 2015.
- ^ Kean, Sam (2015). "The Flavor of Smog". Distillations. 2 (3): 5. Retrieved 22 March 2018.
- ^ Elsevier. "Chemistry of the Natural Atmosphere, Volume 71 - 2nd Edition". www.elsevier.com. Retrieved 15 November 2018.
- PMID 17921528.
- ^ Watson, Traci (16 April 2004). "EPA: Half of USA breathing illegal levels of smog". USA Today. Washington.
- ^ Marziali, Carl (4 March 2015). "L.A.'s Environmental Success Story: Cleaner Air, Healthier Kids". USC News. Retrieved 16 March 2015.
- PMID 26761628.
- ^ "Ozone Pollution". Clean Water Action Council of Northeast Wisconsin.
- ^ "Health Effects of Ozone in the General Population". Ozone and Your Patients' Health: Training for Health Care Providers. United States Environmental Protection Agency. 10 September 2013.
In addition to these effects, evidence from observational studies strongly indicates that higher daily ozone concentrations are associated with increased asthma attacks, increased hospital admissions, increased daily mortality, and other markers of morbidity.
- PMID 27392261.
- ^ Ambient air pollution, smog episodes and mortality in Jinan, China: Jun Zhang, Yao Liu, Liang-liang Cui, Shou-qin Liu, Xi-xiang Yin & Huai-chen Li Scientific Reports 7, Article number: 11209 (2017) doi:10.1038/s41598-017-11338-2
- PMID 31277656.
- ^ "Guidelines for the Reporting of Daily Air Quality – the Air Quality Index (AQI)" (PDF) (EPA-454/B-06-001). United States Environmental Protection Agency, Office of Air Quality Planning and Standards. May 2006.
{{cite journal}}
: Cite journal requires|journal=
(help) - ^ Hamilton, Tyler (9 June 2016). "$3.83 to power hybrid plug-in for 6 days". Wheels.ca. Archived from the original on 18 August 2010.
- ^ Smoggy Skies May Cause Respiratory Death NPR.org
- ^ "Toxic air pollution nanoparticles discovered in the human brain". Lancaster University. 5 September 2016.
- ^ Reuben, Aaron (24 June 2015). "The terrifying truth about air pollution and dementia". Mother Jones.
- PMID 23045474.
- PMID 28871018.
- PMID 24429273.
- S2CID 251430613.
- PMID 10570123.
- ISBN 978-1-100-19064-8. Archived from the original(PDF) on 4 August 2016. Retrieved 18 March 2017.
- ^ Badarinath, K. V. S., Kumar Kharol, S., & Rani Sharma, A. (2009), Long-range transport of aerosols from agriculture crop residue burning in Indo-Gangetic Plains—a study using LIDAR, ground measurements and satellite data. Journal of Atmospheric and Solar-Terrestrial Physics, 71(1), 112–120
- ^ Sharma, A. R., Kharol, S. K., Badarinath, K. V. S., & Singh, D. (2010), Impact of agriculture crop residue burning on atmospheric aerosol loading—a study over Punjab State, India. Annales Geophysicae, 28(2), pp 367–379
- PMID 21465742.
- ^ "Causes of Smog | How to Protect Yourself from Smog - Honeywell Blog". Official Blog Updates - Honeywell Air Purifiers. 26 November 2017. Retrieved 7 March 2018.
- ^ "Delhi is most polluted city in world, Beijing much better: WHO study". Hindustan Times. Archived from the original on 8 May 2014. Retrieved 8 May 2014.
- ^ a b "Delhi's Air Has Become a Lethal Hazard and Nobody Seems to Know What to Do About It". Time magazine. Archived from the original on 2 March 2014. Retrieved 10 February 2014.
- ^ a b "India's Air Pollution Triggers Comparisons with China". Voice of America. Archived from the original on 21 February 2014. Retrieved 20 February 2014.
- ^ "A Delhi particular". The Economist. Retrieved 6 November 2012.
- ^ "How Crop Burning Affects Delhi's Air". Wall Street Journal. Retrieved 15 February 2014.
- ^ a b Harris, Gardiner (25 January 2014). "Beijing's Bad Air Would Be Step Up for Smoggy Delhi". New York Times. Retrieved 27 January 2014.
- ^ Bearak, Max (7 February 2014). "Desperate for Clean Air, Delhi Residents Experiment with Solutions". New York Times. Retrieved 8 February 2014.
- ^ Madison Park (8 May 2014). "Top 20 most polluted cities in the world". CNN.
- ^ "Children in Delhi have lungs of chain-smokers!". India Today. Retrieved 22 February 2014.
- ^ "Pollution increasing lung cancer in Indian women". DNA. 3 February 2014. Retrieved 3 February 2014.
- ^ "Delhi blanketed in thick smog, transport disrupted". Reuters. 18 December 2013. Archived from the original on 20 December 2013. Retrieved 18 December 2013.
- ^ "January days getting colder, tied to rise in pollution". The Times of India. 27 January 2014.
- ^ "Delhi 'third greenest' city". Ndtv.com. Retrieved 11 March 2011.
- ^ a b "Smog city to clean capital How Delhi did it". Express India. Archived from the original on 31 December 2010. Retrieved 11 March 2011.
- ^ Chandra, Neetu (28 April 2013). "Delhi Metro helps reduce vehicular air pollution, indicates research". India Today.
- ^ R. Kumari; A.K. Attri; L. Int Panis; B.R. Gurjar (April 2013). "Emission estimates of Particulate Matter and Heavy Metals from Mobile sources in Delhi (India)". J. Environ. Science & Engg. 55 (2): 127–142.
- ^ "What is the status of air pollution in Delhi?". CSE, India. Retrieved 2 March 2014.
- ^ "Delhi's air quality deteriorating due to burning of agriculture waste". Economic Times.
- ^ "Thick blanket of smog envelopes Delhi, northern India". India Today.
- ^ "Straw burning ban soon to reduce smog in NRC, Times of India, 4 January 2014". The Times of India.
- ^ "Impose 30% cess on diesel cars, panel tells Supreme Court - Times of India". The Times of India. 11 February 2014.
- ^ David G. Streetsa, Joshua S. Fub, Carey J. Jangc, Jiming Haod, Kebin Hed, Xiaoyan Tange, Yuanhang Zhang, Zifa Wangf, Zuopan Lib, Qiang Zhanga, Litao Wangd, Binyu Wangc, Carolyne Yua, Air quality during the 2008 Beijing Olympic Games. Accessed 23 April 2012
- PMID 14698923.
- ISBN 978-0563204411.
- ^ Minney, R. J. (1963). No. 10 Downing Street: A House in History. Boston: Little, Brown & Co. pp. 429–33.
- ^ "The Great Smog Of 1952". The Met Office. Archived from the original on 29 October 2013.
- ^ "When smog was a frequent occurrence". WW2 People's War. BBC. 10 August 2005. Retrieved 3 August 2006.
- ^ "Court orders UK to cut NO2 air pollution". BBC News. BBC. 29 April 2015. Retrieved 29 April 2015.
- ^ "UK Supreme Court orders Government to take "immediate action" on air pollution". ClientEarth. 29 April 2015. Archived from the original on 5 May 2015. Retrieved 29 April 2015.
- ^ SBC.ac.at Archived 14 September 2011 at the Wayback Machine, Air pollution in Mexico City, University of Salzburg
- ^ "Hundreds treated over Tehran smog". BBC News. 10 December 2005. Retrieved 3 August 2006.
- ^ "Popular Science". Bonnier Corporation. 10 October 1933 – via Google Books.
- ^ EPA.gov, The Green Book Nonattainment Areas, Green Book |
- ^ "About AIRNow". AIRNow. 6 May 2013. Archived from the original on 29 October 2013. Retrieved 25 October 2013.
- ^ US EPA, OP (22 February 2013). "Summary of the Clean Air Act". www.epa.gov. Retrieved 13 March 2022.
- ^ Associated Press, 5 June 2019, "AP Fact Check: Trump Didn't Set Records on Clean Air in US"
- ^ Roger G. Noll (1999). The Economics and Politics of the Slowdown in Regulatory Reform.
- ^ "Early Implementation of the Clean Air Act of 1970 in California." EPA Alumni Association. Video, Transcript (see p6). 12 July 2016.
- ^ US EPA, OAR (5 May 2016). "Vehicle Emissions California Waivers and Authorizations". US EPA. Retrieved 26 November 2020.
- ^ Laboratory (CSL), NOAA Chemical Sciences. "NOAA CSL: 2012 News & Events: 50-year decline in some Los Angeles vehicle-related pollutants". csl.noaa.gov.
- ^ "Is clean air worth the cost? A case study for developing megacities". 15 February 2015.
- ^ Jess McNally (2010). "July 26, 1943: L.A. Gets First Big Smog". Wired.
- OCLC 431334523. Retrieved 12 October 2014.
- ^ "World War II and the Postwar Years". Environmental History Timeline. 1948. Archived from the original on 5 February 2011.
- ^ Tracton, Steve (20 December 2012). "The Killer London Smog Event of December 1952: A Reminder of Deadly Smog Events in the US". The Washington Post. Retrieved 25 February 2015.
- ^ Cullen, Andrew (22 March 2010). "Mongolia: Ulaanbaatar Grapples with Smog Problem". EurasiaNet.org. Archived from the original on 28 August 2012. Retrieved 1 October 2012.
- ^ de la Torre, Ferdie (5 October 2006). "Indon haze spreads to NMI". Saigpan Tribune. Archived from the original on 18 February 2007.
- ^ Chelvi, S.Tamarai. "15 areas with unhealthy air (updated)". Petaling Jaya: Sun Media Corporation Sdn. Bhd. Archived from the original on 10 January 2009.
- ^ ASEAN Secretariat, Jl. (28 June 2007). "Combating Haze in ASEAN: Frequently Asked Questions". ASEAN Haze Action Online. Archived from the original on 29 October 2013. Retrieved 25 October 2013.
- ^ "Singapore: PSI hits new all-time high of 401 on Friday". Channel NewsAsia. 21 June 2013. Archived from the original on 24 June 2013.
- ^ ASEAN Secretariat, Jl. "ASEAN Agreement on Transboundary Haze Pollution". ASEAN Haze Action Online. Archived from the original on 10 September 2015. Retrieved 31 January 2019.
- ^ ASEAN Secretariat, Jl. "About Us". ASEAN Haze Action Online. Archived from the original on 12 September 2015. Retrieved 31 January 2019.
- ^ Malaysian Meteorological Department. "Fire Danger Rating System (FDRS) for Southeast Asia". Ministry of Science, Technology, and Innovation (MOSTI), Malaysia. Archived from the original on 29 October 2013. Retrieved 25 October 2013.
- ^ "Smoke signal: Winter smog is a reminder India and Pakistan need to talk about more than geopolitics". Scroll.in. 5 November 2017.
- ^ "Polluted smog covers Pakistan's city of Lahore". Fox News. 5 November 2016. Retrieved 6 November 2016.
- S2CID 245135298.
- ^ Khan, Rina Saeed (24 January 2015). "Lahore smog: It's not a natural phenomenon". dawn.com. Retrieved 6 November 2016.
- ^ Hal Erickson (2013). "A Clear and Present Danger". Movies & TV Dept. The New York Times. Archived from the original on 13 November 2013.
- ISBN 978-1-58567-860-0. Retrieved 31 January 2019.
- Upadhyay, Harikrishna (2016-11-07)"All You Need To Know About Delhi Smog / Air Pollution – 10 Questions Answered", Dainik Bhaskar. Retrieved on 7 November 2016.
Further reading
- Brimblecombe, Peter. "History of air pollution." in Composition, Chemistry and Climate of the Atmosphere (Van Nostrand Reinhold (1995): 1–18
- Brimblecombe, Peter, and László Makra. "Selections from the history of environmental pollution, with special attention to air pollution. Part 2*: From medieval times to the 19th century." International Journal of environment and pollution 23.4 (2005): 351–367.
- Corton, Christine L. London Fog: The Biography (2015)