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 and detrimental for human and animal health.
Air Pollution is the deterioration of the quality of the air to an extent that:
- it becomes difficult to breathe, often toxic or detrimental,
- it complicates the health of living beings,
- it causes the body organs to malfunction,
- it damages the habitats of animal, plants, and other living organisms,
- it poses the threat to the natural environment and its habitats.
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.
Air Pollutants refer to the abnormal substances (solids, liquids, and gases) that are present in air in intolerable limits.
Classification of air pollutants: Air pollutants can also be divided into two categories: primary pollutant and secondary pollutant.
- 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.
- 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.
Major Air Pollutants
The pollutants that contribute major portion of global air pollution are:
- Sulphur Oxides (SOx): These substances are produced by industry, particularly the industrial combustion of fossil fuels. They are also produced naturally when volcanoes erupt.
- Nitrous oxides(N2O): These oxides are released into the atmosphere when industrial combustion occurs at high temperatures.
- Carbon monoxide (CO): When fuels (especially wood, oil, coal and natural gas) do not burn ‘cleanly’ (i.e. their combustion is incomplete), they can emit carbon monoxide. One of the main sources of CO is exhaust fumes from vehicles such as cars.
- Carbon dioxide (CO2): This noxious gas is another pollutant released when fossil fuels are burnt.
- Particulates: Small particles can be released into the air by aerosol use and by the combustion of fossil fuels (for example, soot is released when coal is burned).
Besides above, nitrogen oxide (NOx) and hydrocarbons (H.C.) are major pollutants. Further, organic and inorganic acids, bacteria, viruses, insecticides, etc. pollutes the air.
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. The major pollutants from natural sources includes:
- 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) includes:
- 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.
The impact of air pollution.
1. Acid rain: Acid compounds in the air dissolve into the rain and make the rain acidic. When it falls, acid rain can erode buildings and poison the earth and sea. It also degrades the soil quality, decreases farm output, and damages forests.
2. Smog: Particulates can cause thick, gloomy clouds in the air. This can severely limit visibility, and is a particular problem in big cities where vehicle use is very heavy.
3. Respiratory problems in humans: Sulfides, nitrous oxides and carbon monoxide can all cause respiratory illness in humans In high quantities or over long periods of time, these pollutants can also be fatal.
4. Global warming: Greenhouse gases are a group of pollutants (for instance CO and SO) which form a layer in the atmosphere above the earth which traps in the sun’s rays and causes them to reflect back onto the earth. This warms up the earth and is known as the greenhouse effect because it essentially turns the earth into a giant greenhouse filled with heat.
5. The acidification of the oceans: If the air is polluted, these pollutants can dissolve into the oceans and saturate them with carbon, particulates, sulfides and nitrates. In this way, air pollution turns into water pollution as well, spoiling the habitats of marine and freshwater life.
6. Freak weather: Global warming does not just cause global temperatures of earth and sea to rise. It also causes freak weather events such as huge blizzards, forest fires, tsunamis and so on. This disrupts agriculture, destroys animals’ habitats and causes poverty, drought and the displacement of vast numbers of human beings across the face of the earth.
How to Control Air Pollution?
Much of the air pollution is caused due to human activity. The following remedial measures can be taken to control air pollution:
- Plant more trees. Trees absorb greenhouses gases such as CO2 and releases O2 into the air.
- Use fewer vehicles. Vehicles releases much of the pollutants into the air. An alternative way to save air polluting is to start using e-vehicles.
- Use less fossil fuels. Fossil fuels such as coal, when burned, releases massive quantity of polluting gases into the environment.
- Make use of Renewable energy. Unlike thermal power plants, that pollutes the air, renewable sources of power such as hydro power, wind power, solar power, etc., are comparatively less polluting.
- Use green technologies. Unlike traditional factories, that releases a lot of polluting fumes in the air, modern green plants releases a minimal of polluting gases.
Air pollution is a huge problem, and it is one that humans have caused. As such, humans have a responsibility to fix it as well. We should all act now to end air pollution and thus to make the world a happier and healthier place for both humans and animals.
Also read: 10 Ways to reduce and control air pollution
Also read: Air Pollution (Wikipedia)
Contributors: (1) Vishal, (2) Laura