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3. Air pollution wet & dry smog, indoor pollution

Smog is a combination of smoke and fog, which creates air pollution (Smog = smoke + fog).

Wet smog, or London Great smog (1952) – pollution containing acid smoke from burning coal.

History: London, 5-10 December 1952, 4000 people died from respiratory diseases. In 2002 the official death toll was raised from 4,000 to nearly 12,000.

The major agents: sulfur dioxide SO2, mist, soot particles.

The primary factors: low temperature (t=0°C); high atmospheric pressure, early morning, temperature inversion.

Wet smog causes reduced visibility and damage of respiratory system.

Photochemical smog (dry smog), or Los Angeles smog – air pollution during which relatively high level of ground-level ozone, is present at low altitudes as a result of the light-induced reaction of pollutants:

VOCs + NO' + sunlight → O3 + HNO3 + organics

VOCs – Volatile Organic Compounds – the unburnt hydrocarbons and their derivatives emitted into the air as pollutants from internal combustion engines and other sources.

Urban ozone – “Ozone layer in the wrong place" (to contrast it with the stratospheric ozone depletion). The smog often has a brown haze due to the presence of nitrogen dioxide

The major agents: tropospheric ozone (urban ozone, or “bad ozone”) – secondary pollutant.

The primary factors: high temperature (t0 =24-320); low atmospheric pressure, midday, temperature inversion.

Dry smog causes vision reduction and irritation of eyes, nose, and throat.

The main physical reason of the smog is the atmospheric temperature inversion.

Temperature inversion – a phenomenon which occurs where ground air cools quickly than upper levels.

This temperature differential prevents air mixing and traps pollutants close to the ground.

Today - Almaty is one of ten most polluted cities in the world. The data is the result of the research of the international consulting company Mercer Human Resource Consulting, the agency reports referring to the news agency newsru.

Company Mercer made the list of the most polluted cities in the world, having their data based on level of air pollution, the degree of waste recycling, quality of drinking water, presence of hospital services, medical equipment and presence of infectious diseases in 215 large cities of the world.

1. Baku, Azerbaijan. Pollution index: 27.6. High level of air pollution due to oil extraction. 2. Dacca, Bangladesh. Pollution index: 29.6. High level of water pollution. 3. Antananarivo, Madagascar. Pollution index: 30.1. 4. Port-o-Prins, Haiti. Pollution index: 34. 5. Mexico City, Mexico. Pollution index: 37.7. 6. Addis Ababa, Ethiopia. Pollution index: 37.9. 7. Mumbay, India. Pollution index: 38.2. 1 billion is required to restore ecology of the city. 8. Bagdad, Iraq. Pollution index: 39. Military actions in Iraq and burning of oil deposits became the reason of air pollution in the city. 9. Almaty (Alma-Ata), Kazakhstan. Pollution index: 39.1. 10. Brazzaville, Congo. Pollution index: 39.1. High degree of pollution, shortage of drinking water and water pollution of the city due to wastes. The cleanest city in the world has been recognized the Canadian Calgary. Pollution index made 131.7.