Smog

:For the rock band named Smog, see Smog (band).

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Smog is a kind of heavy air pollution. Under weather conditions that prevent circulation of air, it can stay for an extended period of time over densely populated cities, such as London, Los Angeles, Santiago, Athens, Beijing, Hong Kong or the Ruhr Area and build up to dangerous levels. The word "smog" is a portmanteau constructed from the words "smoke" and "fog", although modern usage of the term does not require either a smoke or fog component and "smog" is often used as shorthand for "air pollution". The term was first coined by Dr. 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, ?e 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.?? The following day the newspaper stated that ?Dr Des Voeux did a public service in coining a new word for the London fog.?

Related Topics:
Air pollution - Weather - London - Los Angeles - Santiago - Athens - Beijing - Hong Kong - Ruhr Area - Portmanteau - Smoke - Fog - Dr. Henry Antoine Des Voeux - Public Health Congress

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

There are two major varieties of smog. Photochemical smog is associated with cities such as Los Angeles and oil combustion while reducing smog is associated with London and the use of coal and other sulphur-rich fossil fuels.

Related Topics:
Photochemical smog - Coal - Sulphur - Fossil fuels

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Photochemical smog is caused when two kinds of air pollution combine in the presence of sunlight. The first kind is the particulates and nitric oxides from the exhaust of fossil fuel-burning engines in cars, trucks, coal power plants, and industrial manufacturing factories. The second kind is the emission of volatile organic compounds from paints, solvents, pesticides, and other chemicals. According to the Clean Water Action Council of Northeastern Wiscounsin, gasoline and other petroleum-based chemicals and solvents often vaporize directly into the atmosphere, contributing to ozone. Two major residential sources are gasoline-powered lawnmowers and the starter fluid for backyard grills.

Related Topics:
Photochemical smog - Pollution - Sunlight - Particulate - Nitric oxide - Fossil fuel - Cars - Coal - Power plant - Volatile organic compound - Paint - Solvent - Pesticide - Chemical - Gasoline - Ozone - Lawnmower

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Smog can form in almost every climate, but is far 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.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Episodes of smog became common in London in the late 19th century and were nicknamed "pea-soupers". The Great Smog of 1952 darkened the skies over London and killed approximately 12,000 people. The British government first blamed a flu epidemic, reluctant to admit that coal smoke was to blame. In 1956 the Clean Air Act introduced smokeless zones to the capital. Only smokeless fuels could be used in these areas. Consequently, reduced sulphur dioxide levels made the intense and persistent London smog a thing of the past. Smog caused by traffic pollution, however, does occur in modern London.

Related Topics:
London - 19th century - Great Smog of 1952 - Flu - Epidemic - 1956 - Clean Air Act - Sulphur dioxide

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Smog is a problem in a number of cities and continues to harm life. According to the U.S. EPA, air is unhealthy because of smog if it contains more than 80 parts per billion (ppb)or 0.5 ppm of ozone (the primary component of smog) http://www.usatoday.com/weather/news/2004-04-15-air-quality-ap_x.htm, more than 53 ppb of nitrogen dioxide or 80 ppb particulates. High levels of smog aggravate and even cause human respiratory problems, including emphysema, bronchitis, and asthma. Hospital admissions and respiratory deaths often increase during periods when ozone levels are high http://www.cwac.net/air_pollution/ozone.html.

Related Topics:
EPA - Ozone - Nitrogen dioxide - Emphysema - Bronchitis - Asthma

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

An erupting volcano can also emit high levels of sulfur dioxide, creating volcanic smog, or vog.

Related Topics:
Volcano - Sulfur dioxide - Vog

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The burning of forests in Indonesia has on a number of occasions created prolonged smog-like haze, which have extended to parts of Malaysia, Philippines, Singapore and Thailand.

Related Topics:
Forests - Indonesia - Haze - Malaysia - Philippines - Singapore - Thailand

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The high density of factories located in Mainland China polluted Hong Kong. Now, Hong Kong's skyscrapers can barely be seen.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~