Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a portmanteau of the words smoke and fog to refer to smoky fog due to its opacity, and odor. The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid-20th century, where it was commonly known as a London particular or London fog. This kind of visible air pollution is composed of nitrogen oxides, sulfur oxide, ozone, smoke and other particulates. Man-made smog is derived from coal combustion emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions.
Jilin is one of the three provinces of Northeast China. Its capital and largest city is Changchun. Jilin borders North Korea and Russia to the east, Heilongjiang to the north, Liaoning to the south, and Inner Mongolia to the west.
Jilin City is the second-largest city and former capital of Jilin province in northeast China. As of the 2020 census, 3,623,713 people resided within its administrative area of 27,166.37 square kilometres (10,488.99 sq mi) and 1,895,865 in its built-up area consisting of four urban districts. A prefecture-level city, it is the only major city nationally that shares its name with its province.
The Jilin chemical plant explosions were a series of explosions which occurred on November 13, 2005, in the No.102 Petrochemical Plant in Jilin City, Jilin Province, China, over the period of an hour. The explosions killed six, injured dozens, and caused the evacuation of tens of thousands of residents.
The Capitol Power Plant is a fossil-fuel burning power plant which provides steam and chilled water for the United States Capitol, the Supreme Court, the Library of Congress and 19 other buildings in the Capitol Complex. Located at 25 E St SE in southeast Washington, D.C., the CPP was the only coal-burning power plant in the District of Columbia, and it now mostly uses natural gas. The plant has been serving the Capitol since 1910, and is under the administration of the Architect of the Capitol.
Pollution in China is one aspect of the broader topic of environmental issues in China. Various forms of pollution have increased following the industrialisation of China, causing widespread environmental and health problems.
Air pollution in Hong Kong is considered a serious problem. Cases of asthma and bronchial infections have soared due to reduced air quality.
Air Pollution in Mexico City has been of concern to the city's population and health officials for decades. In the 20th century, Mexico City's population rapidly increased as industrialization brought thousands of migrants from all over the world. Such a rapid and unexpected growth led to the UN declaring Mexico City as the most polluted city in the world in 1992. This was partly due to Mexico City's high altitude, which causes its oxygen levels to be 25% lower. Carbon-based fuels also do not combust completely. Other factors include the proliferation of vehicles, rapid industrial growth, and the population boom. The Mexican government has several active plans to reduce emission levels which require citizen participation, vehicular restrictions, increase of green areas, and expanded bicycle accessibility.
Particulates or atmospheric particulate matter are microscopic particles of solid or liquid matter suspended in the air. The term aerosol refers to the particulate/air mixture, as opposed to the particulate matter alone, though it is sometimes defined as a subset of aerosol terminology. Sources of particulate matter can be natural or anthropogenic. They have impacts on climate and precipitation that adversely affect human health, in ways additional to direct inhalation.
The Air Quality Health Index (AQHI) is a scale designed in Canada to help understand the impact of air quality on health. It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. The Air Quality Health Index also provides advice on how to improve air quality by proposing behavioral change to reduce the environmental footprint. This index pays particular attention to people who are sensitive to air pollution. It provides them with advice on how to protect their health during air quality levels associated with low, moderate, high and very high health risks.
Air pollution in India is a serious environmental issue. Of the 30 most polluted cities in the world, 21 were in India in 2019. As per a study based on 2016 data, at least 140 million people in India breathe air that is 10 times or more over the WHO safe limit and 13 of the world's 20 cities with the highest annual levels of air pollution are in India. The main contributors to India's particulate air pollution include industrial and vehicular emissions, construction dust and debris, dependence on thermal power for electricity, waste burning, and use of wood and dung by low-income and rural households for cooking and heating. 51% of India's air pollution is caused by industrial pollution, 27% by vehicles, 17% by crop burning and 5% by other sources. Air pollution contributes to the premature deaths of 2 million Indians every year. Emissions come from vehicles and industry, whereas in rural areas, much of the pollution stems from biomass burning for cooking and keeping warm. In autumn and spring months, large scale crop residue burning in agriculture fields – a cheaper alternative to mechanical tilling – is a major source of smoke, smog and particulate pollution. India has a low per capita emissions of greenhouse gases but the country as a whole is the third largest greenhouse gas producer after China and the United States. A 2013 study on non-smokers has found that Indians have 30% weaker lung function than Europeans.
The 2013 Eastern China smog was a severe air pollution episode that affected East China, including all or parts of the municipalities of Shanghai and Tianjin, and the provinces of Hebei, Shandong, Jiangsu, Anhui, Henan, and Zhejiang, during December 2013. A lack of cold air flow, combined with slow-moving air masses carrying industrial emissions, collected airborne pollutants to form a thick layer of smog over the region. Levels of PM2.5 particulate matter averaged over 150 micrograms per cubic metre; in some areas, they were 300 to 500 micrograms per cubic metre.
APEC blue refers to the rare blue sky in Beijing during APEC China 2014 due to emission reduction campaign directed by Chinese government. Because of its transience, the new phrase "APEC blue" also refers to something wonderful but also fleeting.
The air pollution in Delhi, the capital territory of India, was found to be the worst of any major city in the world in an August 2022 survey of 7,000 world cities by the US-based Health Effects Institute. The air pollution in Delhi also affects the surrounding districts. Air pollution in India is estimated to kill about 2 million people every year and is the fifth largest killer in India. India has the world's highest death rate from chronic respiratory diseases and asthma, according to the World Health Organization. In Delhi, poor air quality has irreversibly damaged the lungs of 2.2 million children.
The World Health Organization guidelines were most recently updated in 2021. The guidelines offer guidance about these air pollutants: particulate matter (PM), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO). The WHO first released the air quality guidelines in 1987, then updated them in 1997. The reports provide guidelines intending to give guidelines to reduce the health effects of air pollution.
Air pollution in Taiwan is mostly derived from sources of domestic combustion, primarily the burning of fossil fuels. Taiwan's topography has been noted to be a contributing factor to its air pollution problem, leading to poor dispersal and trapping pollutants. Taipei, Taiwan's capital and largest city for example, is surrounded by mountains, and other industrial centers along the northern and western coasts of Taiwan are surrounded by high mountains.
Smog towers or smog free towers are structures designed as large-scale air purifiers to reduce air pollution particles (smog). This approach to the problem of urban air pollution involves air filtration and removal of suspended mechanical particulates such as soot and requires energy or power. Another approach is to remove urban air pollution by a chimney effect in a tall stack or updraft tower, which may be either filtered or released at altitude as with a solar updraft tower and which may not require operating energy beyond what may be produced by the updraft.
The 2021 East Asia sandstorm was a meteorological phenomenon that began in the Eastern Gobi desert steppe on March 14, and subsequently spread to the entire Mongolian Plateau South, the Loess Plateau, the North China Plain and the Korean Peninsula. It was caused by strong northwest winds coming in from Mongolia, as a result of hot and dry conditions.
The 2025 Bangkok smog was a severe air pollution event affecting the Bangkok Metropolitan Region beginning in January 2025.
