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.
In meteorology, an inversion is a phenomenon in which a layer of warmer air overlies cooler air. Normally, air temperature gradually decreases as altitude increases, but this relationship is reversed in an inversion.
The Great Smog of London, or Great Smog of 1952, was a severe air pollution event that affected London, England, in December 1952. A period of unusually cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants—mostly arising from the use of coal—to form a thick layer of smog over the city. It lasted from Friday 5 December to Tuesday 9 December 1952, then dispersed quickly when the weather changed.
Haze is traditionally an atmospheric phenomenon in which dust, smoke, and other dry particulates suspended in air obscure visibility and the clarity of the sky. The World Meteorological Organization manual of codes includes a classification of particulates causing horizontal obscuration into categories of fog, ice fog, steam fog, mist, haze, smoke, volcanic ash, dust, sand, and snow. Sources for particles that cause haze include farming, traffic, industry, windy weather, volcanic activity and wildfires. Seen from afar and depending on the direction of view with respect to the Sun, haze may appear brownish or bluish, while mist tends to be bluish grey instead. Whereas haze often is considered a phenomenon occurring in dry air, mist formation is a phenomenon in saturated, humid air. However, haze particles may act as condensation nuclei that leads to the subsequent vapor condensation and formation of mist droplets; such forms of haze are known as "wet haze".
The Clean Air Act 1956 was an Act of the Parliament of the United Kingdom enacted principally in response to London's Great Smog of 1952. It was sponsored by the Ministry of Housing and Local Government in England and the Department of Health for Scotland, and was in effect until 1993.
The 1939 St. Louis smog was a severe smog episode that affected St. Louis, Missouri on November 28, 1939. Visibility was so limited that streetlights remained lit throughout the day and motorists needed their headlights to navigate city streets.
Fumifugium, or, The inconveniencie of the aer and smoak of London dissipated together with some remedies humbly proposed by J.E. esq. to His Sacred Majestie, and to the Parliament now assembled is a pamphlet published in London, 1661, by John Evelyn. It is one of the earliest known works on air pollution and is still considered a significant contribution to the literature on the subject over three and half centuries after its publication. The letter was specifically addressed to King Charles II of England and discussed problems with the capital's air pollution dating back to medieval times. Evelyn refers to Greek philosophers, who once believed that air was the principle of the earth and primary substance of the soul up until the time that air pollution began to cause ill health.
Air pollution is the contamination of air due to the presence of substances called pollutants in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. It is also the contamination of the indoor or outdoor environment either by chemical, physical, or biological agents that alters the natural features of the atmosphere. There are many different types of air pollutants, such as gases, particulates and biological molecules. Air pollution can cause diseases, allergies, and even death to humans; it can also cause harm to other living organisms such as animals and crops, and may damage the natural environment or built environment. Air pollution can be caused by both human activities and natural phenomena.
Smokeless fuel is a type of solid fuel which either does not emit visible smoke or emits minimal amounts during combustion. These types of fuel find use where the use of fuels which produce smoke, such as coal and unseasoned or wet wood, is prohibited.
The 1948 Donora smog killed 20 people and caused respiratory problems for 6,000 of the 14,000 people living in Donora, Pennsylvania, a mill town on the Monongahela River 24 miles (39 km) southeast of Pittsburgh. The event is commemorated by the Donora Smog Museum.
Air pollution in the United Kingdom has long been considered a significant health issue, and it causes numerous other environmental problems such as damage to buildings, forests, and crops. Many areas, including major cities like London, are found to be significantly and regularly above legal and recommended pollution levels. Air pollution in the UK is a major cause of diseases such as asthma, lung disease, stroke, cancer, and heart disease, and is estimated to cause forty thousand premature deaths each year, which is about 8.3% of deaths, while costing around £40 billion each year.
A dense wave of smog began in Northeast China, especially in major cities including Harbin, Changchun and Shenyang, as well as the surrounding Heilongjiang, Jilin, and Liaoning provinces on 20 October 2013. Unseasonably warm temperatures with very little wind across northeastern China coincided with the initiation of Northeast China's coal-powered municipal heating system. Record densities of fine particulates were measured in the city.
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.
Air pollution measurement is the process of collecting and measuring the components of air pollution, notably gases and particulates. The earliest devices used to measure pollution include rain gauges, Ringelmann charts for measuring smoke, and simple soot and dust collectors known as deposit gauges. Modern air pollution measurement is largely automated and carried out using many different devices and techniques. These range from simple absorbent test tubes known as diffusion tubes through to highly sophisticated chemical and physical sensors that give almost real-time pollution measurements, which are used to generate air quality indexes.
The 1966 New York City smog was a major air-pollution episode and environmental disaster, coinciding with that year's Thanksgiving holiday weekend. Smog covered the city and its surrounding area from November 23 to 26, filling the city's air with damaging levels of several toxic pollutants. It was the third major smog in New York City, following events of similar scale in 1953 and 1963.
The 1962 London smog was a severe smog episode that affected London, England, in December 1962. It occurred ten years after the Great Smog of London, in which serious air pollution had killed as many as 12,000 people. While the 1952 smog had led to the passing of the 1956 Clean Air Act, which restricted the burning of domestic fuels in urban areas with the introduction of smokeless zones, fogs continued to be smoky in London for some years after the act as residents and operators were given time to convert from domestic fuels. The December 1962 smog is thought to have led to the deaths of up to 700 people.
The Harvard "Six Cities" study was a major epidemiological study of over 8,000 adults in six American cities that helped to establish the connection between fine-particulate air pollution and reduced life expectancy. Widely acknowledged as a landmark piece of public health research, it was initiated by Benjamin G. Ferris, Jr at Harvard School of Public Health and carried out by Harvard's Douglas Dockery, C. Arden Pope of Brigham Young University, Ferris himself, Frank E. Speizer, and four other collaborators, and published in the New England Journal of Medicine in 1993. Following a lawsuit by The American Lung Association, the study, and its various follow-ups, led to a tightening of pollution standards by the US Environmental Protection Agency. This prompted an intense backlash from industry groups in the late 1990s, culminating in a Supreme Court case, in what Science magazine termed "the biggest environmental fight of the decade".
John Switzer Owens was an Irish physician and environmental engineer. He invented some of the first scientific instruments for collecting and measuring air pollution and helped to establish the first large-scale pollution monitoring network in the United Kingdom.
A deposit gauge is a large, funnel-like scientific instrument used for capturing and measuring atmospheric particulates, notably soot, carried in air pollution and "deposited" back down to ground.
Peter Brimblecombe is an Australian-born, British atmospheric chemist, currently emeritus professor of atmospheric chemistry at the University of East Anglia and National Sun Yat-sen University in Taiwan. In a five-decade research career, he has written or co-authored seven books and around 350 peer-reviewed papers on air pollution and its effects on human health and the environment, but is probably best known as the author of The Big Smoke, which has been described as a definitive history of air pollution.
