Air Pollution, Sources pollutants and units.

Air Pollution is the presence of contaminants released by human activities into the earth's atmosphere having potential of causing harm to property or the precious lives of plants, animals or humans.

Sources of Air pollution 

Air pollution is caused by various types pf pollutants. Petroleum refineries release poisonous gases like sulfur dioxide, nitrogen oxides etc.

Natural Sources: Volcanos, forest fire, dust storm, oceans, plants.

Anthropogenic sources: Created by human beings.

Stationary sources

Point sources:- Industrial processing power plants, fuel combination etc.

Area Sources:- Residential heating coal gas oil, on site incineration, open burning etc.

Mobile sources 

Line sources Highway vehicle, rail road locomotive etc.

Air pollutants

Any substances occurring in the  atmosphere that may have adverse effects on humans, animals, plant life is known as an air pollutant.

Criteria Air pollutants:

Criteria air pollutants in a term used internationally to describe air pollutants that have been regulated and are used as indicators of air quality.

Based on National Ambient Air Quality Standards (NAAQS).

Primary Air pollutants 

These pollutants emitted directly from the identifiable sources are as given below

➜Oxides of sulfur (Particularly SO₂ )

➜Oxides of carbon (CO and SO₂ )

➜Oxides of nitrogen (NO_x )

➜Hydrocarbons

➜Suspended Particulate Matter (SPM)

Secondary Air Pollutants

These are produced from the chemical reaction of natural or anthropogenic primary pollutants due to their oxidation, these are more harmful.

➜Sulfuric  Acid (H₂SO₄ )

➜Ozone (O₃ )

➜Formaldehyde (HCHO)

➜Peroxy-Acyl Nitrate (PAN) etc.

Units of Measure of Air Pollutants

There are three basic units

➜Microgram per cubic metre (μց∕m3)

➜Parts per million (ppm)

➜Micron or its equivalent ( μm).

➜(μց/m3) and (ppm) are used to indicate concentration of gaseous  pollutants.

➜(μm) is used to report particle size.