The air pollutants can be classified in many ways as shown below:-
- According to origin: The air pollutants are classified into:
Primary pollutants:
The pollutants that are emitted directly from identifiable sources produced by natural events
( eg: dust storms and volcanic eruptions) and human activities (eg: emissions from vehicles, industries etc.) are called primary pollutants. Eg: smoke, dust, oxides of sulphur & nitrogen, hydrocarbons and particulate matter etc. Secondary pollutants:
The pollutants that are formed in the atmosphere by chemical interactions between primary pollutants and atmospheric constituents are known as secondary pollutants. Eg. Sulphur trioxide, ozone, ketones, sulphuric acid, nitric acid, carbonic acid etc.
- According to state of matter: The pollutants are classified into:-
Gaseous air pollutants:
These pollutants exist in a gaseous state at normal temperature and pressure. They are carbon dioxide, nitrogen dioxide, sulphur oxides etc.
Particulate air pollutants:
These are not gaseous substances. They are suspended droplets, solid particles or mixtures of the two.
- According to sources: Pollutants originate from
Natural sources:
These include volcanic eruptions, deflation of sand and dust, forest or wild fires of natural vegetation, sulphur springs, natural geysers, organic and inorganic decays, vegetative decays, marsh gases, cosmic dust, pollen grains of flowers, photochemical reactions, soil debris etc.
Man-made sources:
These include human activities such as industries, factories, urban centres, aircraft, nuclear experiments, automobiles, agriculture, domestic burning of wood and burning of fossil fuels, deforestation, mining, waste treatment plants and power plants. ch is injurious to health, of human, animal or plant life or which interferes with the comfortable enjoyment of life and prosperity” is known as air pollution.
|
Participants