Introduction and Meaning: Air pollution is the presence of harmful foreign substances (pollutants) in the atmosphere, emitted by both natural and anthropogenic (human activity) sources.
Air pollution is the contamination or presence of unwanted substances in the air making it harmful for human and animal health.
Air Pollution is condition when the quality of air deteriorates to an extent that it becomes difficult to breathe.
For example, the emissions from industries and motor vehicles pollutes the air to an extent that causes damage to living organisms.
Pure air is necessary for our health. Air pollution is the leading cause of several diseases. During the past few years, air pollution has emerged as one of the leading causes of death worldwide.
What causes Air Pollution? The air is polluted in different ways. It is polluted through industrialization, urbanization, and motorization. It is polluted by thermal plants, installation of chemical and petrochemical plants and rapid increase of motor vehicles, deforestation and test of modern weapons. Greenhouse gases released by large industries are largely responsible for air pollution.
Also read: Air Pollution: Meaning, Causes, Effects, Solution.
Air Pollutants: Air Pollutants refer to the abnormal substances (solids, liquids, and gases) that are present in air in intolerable limits.
The pollutants that contribute major portion of global air pollution are:
- Carbon Monoxide (CO)
- Nitrogen Oxide (NOx.)
- Hydrocarbons (H.C.)
- Sulphur Oxides (SOx)
- Other particulars
Other than the above-mentioned pollutants, organic and inorganic acids, bacteria, viruses, insecticides, etc. pollutes the air.
Also read: Essay on Environmental Pollution: Causes, Effects and Solution
Characteristics: The characteristics of Air pollution of a particular region or location is influenced by:
- The type of air pollutants and its magnitude.
- The source of emission of the air pollutants.
- The topographical and meteorological conditions of the region.
- The manner in which the pollutants are mixed with the atmospheric air.
- The raw materials used by the industries emitting the pollutants.
- The science and engineering technology used in the manufacturing process and the quantum of emissions discharged.
- The manner in which the discharges are released into the environment.
- The density of population of the region.
- The extent of industrialization in the area.
- The extent of deforestation and the forest cover of the region.
Sources of air pollutants
Major sources of air pollution includes both natural sources and man-made source (anthropogenic).
A. Natural sources:
The natural sources of air pollutants includes volcanic eruptions, forest fires, deflation of sands and dusts, storms, etc.
Pollutants from natural sources
Volcanic pollutants are produced as a result of volcanic activities. Examples: ashes, smokes, carbon dioxide, chlorine, sulfur, dust and other gases.
Land surface pollutants often get mixed with earth’s atmosphere. The dust, sand, soil particles, salt, etc. are the examples of land pollutants.
The cosmic particles and rays, comets, etc. are the natural sources of air pollution.
Green plants and vegetation that produces Volatile organic compounds (VOC) in large quantity are indirect pollutants.
B. Anthropogenic (Man-made sources)
Industries, automobiles, agriculture, power plants, domestic sources, etc. are the man-made or anthropogenic sources of air pollution.
Pollutants from anthropogenic sources (human activity or man-made sources)
Industrial air pollutants are the harmful substances that are released into the air during the manufacturing, production and other industrial process. The smokes, fumes, etc. emitted from large industries and power plants are the examples of industrial air pollutants. The dust and particulate matters also gets mixed with air to worsen the situation.
Domestic air pollutants are the contaminated chemicals and substances that released into the air as a result of household activities. The domestic sources of air pollutant includes gases from kitchen, burning of coal gas, fuel wood, etc.
Vehicular pollutants are emitted by various automobiles. The mixes and polluted the air. For example, the smoke, gases, fumes, emissions from surface, water and air transport vehicles causes pollution.
Agricultural activities also involves the introduction of pollutants into the environment. When insecticides, pesticides and herbicides are sprayed on agricultural fields, they also get mixed with air. This results to an increase in air pollution of the surrounding environment.
Pollutants from fossil-fuel based power plants: The heavy dependence on fossil fuels for meeting the power requirement has done much damage to our environment. When fossil fuels are burnt, the produces several harmful gases including CO2. The heat generated from the power plants negatively affects the environment. The smokes and fly ash that is discharged get mixed with air.
Also read: 10 Ways to reduce and control air pollution
Classification of Air Pollutants
Air pollutants can also be divided into two categories: primary pollutant and secondary pollutant.
1. Primary pollutants
Primary pollutants are emitted directly from the sources. The example of primary pollutant includes carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide, nitric-oxide, ammonia, hydrogen sulphide, and radioactive substances. Industrial fumes and smokes, ash, dust, mist, are other primary sources of air pollution.
2. Secondary pollutants
The secondary pollutants are not emitted from the sources. They are formed when primary pollutants interact with atmospheric constituents. Example includes sulphur-trioxide (SO3), nitrogen-trioxide, ozone (O3), hydrocarbons, acid rain, etc.
Also read: Air Pollution (Wikipedia)
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