Physical Geography 101

Air Pollution

What is air pollution?

Brief History of Air Pollution

First human produced air pollution:
Early accounts of air pollution:
In 1273, King Edward I Longshanks of England banned the use of sea coal.
- the first "Clean Air Act"
By 1850 the Industrial Revolution had started in Europe and North America
London became known for its "pea-soup" fog - not a true fog, but a mixture of fog and smoke
In 1873 one such fog killed 700 people
In 1911 another killed 1150 people
- at this time a London physician, Harold Des Voeux, coined the term "smog" - smoke and fog
In 1952 nearly 4000 people died in one of the killer smogs.
Great Britian passes its first Clean Air Act in _____.
United States passes its first Clean Air Act in _____.

Types and Sources of Air Pollutants

Carbon Monoxide - CO
A colorless, odorless, poisonous gas
Dangerous because red blood cells will more readily carry CO than oxygen, O2

Sulfur Dixide - SO2
Colorless gas, produced by combustion of sulfur bearing fossil fuels (coal, oil)
Primary sources:
Natural sources:

Nitrogen Oxides - NOx
Forms during high temperature combustion of fuel
Nitrogen dioxide - NO2
Nitric oxide - NO
Nitrogen dioxide reacts with water to form Nitric Acid - HNO3
Nitric acid is a main component of acid rain

Compounds composed dominantly hydrogen, H and carbon, C
Methane, CH4 is a hydrocarbon
Benzene, formaldehyde and CFCs
Many hydrocarbons are carcinogenic

Any solid or liquid particle

Temperature Inversions

Inversions occur when the temperature of an air mass increases with increasing altitude.
Normally, warm pollution rises.
During an inversion, warm pollutants are unable to rise.
- quickly reaches the temperature of the surrounding air.

Pollution Domes and Plumes

Pollution domes develop around sources of pollution (city or industrial complexes) when there is a stable air mass (no wind) - the pollutants remain over the source forming a dome of pollution.
Pollution plumes develop when wind carries the pollutants away from the source area.

Global Dimming

Since 1950, solar radiation has decreased by 9 to 30% on various parts of the globe.
Caused by particle pollution:

Other Forms of Pollution