Atmospheric pollution

Atmospheric pollution is the presence of undesirable matters in the air in large quantities, which have harmful effects. These are harmful to humans, vegetation, and other living beings. It occurs in many forms but is generally considered gaseous pollutants present in the atmosphere. Atmospheric pollution could be a result of manufacturing from industries and household activities.

Where does atmospheric pollution occur?

The troposphere is the lowest layer of the earth’s atmosphere, which spans up to 10 km from the earth’s surface. This is the closest region to human beings. Above this region lies the stratosphere, which is filled with ozone gas. Most of the atmospheric pollution occurs in these two layers of the atmosphere. Since the troposphere is at ground level, the pollutants are life-threatening. It also traps the heat and greenhouse gases contributing to climate change.

Causes of atmospheric pollution

The burning of fossil fuels such as coal, gas, oil, etc., is one of the major causes of atmospheric pollution. This releases carbon oxides at a severely high level, which is harmful to the atmosphere. It also emits other types of toxic pollutants into the air. Industrial emission is another major cause of atmospheric pollution. Major pollutants emitting from industries are particulate matter 2.5 and 10, Nitrogen dioxide, sulphur dioxide, and carbon monoxide.

Along with this, many indoor activities also cause atmospheric pollution. The use of chemicals containing Volatile Organic Compounds (VOCs) or ACs causing uneven temperature and even inadequate ventilation are causes of atmospheric pollution.

Pollutants from human activities are significant contributors to atmospheric pollution, and it is caused by motor vehicles, garbage, electricity generation, and excessive consumer products.

Sources of atmospheric pollution

The sources of atmospheric pollution are divided on the basis of areas where they originate and their movement.

1. Mobile sources= this is caused by factors which can move. This generally includes vehicles and other tools powered by something that could create pollutants. It has gases from cars, buses, construction equipment, boats, aeroplanes, trains, etc.
2. Stationary= as the name suggests, these are the sources that don’t move. It is also known as a point source. This includes sources like factories, power plants, residential wood burners, etc. Along with these is the construction of housing developments, dry lakes, and landfills.
3. Agriculture= the agriculture sector contributes to pollution increase by operations undertaken under the sector such as animal barns, manure storage pits, fertilisers, pesticides, etc. Manure emits ammonia into the air, which contributes to atmospheric pollution.
4. Natural sources= this includes the sources caused by forces and activities of nature. This could include dust blowing due to wind, volcanic eruptions which throw gaseous pollutants into the air, or even wildfires.

Mobile sources are responsible for more than half of the pollution. Stationary sources are placed second when it comes to the amount of pollution caused by it. On the other hand, pollution due to agricultural activities and natural causes is less than the first two. They do not cause significant harm to the atmosphere and are not lethal even long-term.

Types of atmospheric pollutants

Atmospheric pollution is divided into two categories depending on the matter of the pollutants. It could be gas or solid form:

Gaseous pollutants 

The pollutants in gas form are known as gaseous pollutants. There are a few major pollutants under this category:

Carbon oxide

Carbon dioxide and carbon monoxide contribute to a major part of the pollution and are called greenhouse gases. Human activities are major sources of these extremely harmful gases. The major source of carbon monoxide is the burning of fossil fuels like coal, charcoal, wood, etc. Old vehicles are also a significant source of carbon monoxide emissions. On the other hand, carbon dioxide is an essential gas for the process of nature. However, carbon dioxide is harmful when present in the atmosphere in large amounts.

Sulphur oxide

One of the major oxides which are dangerous is a higher concentration of sulphur dioxide. Although it naturally occurs during volcanic eruptions, natural causes are not the major source of this pollutant. It is released when fuel containing sulphur, such as coal, oil, etc., is burned. Also, industries release untreated sulphur into the air.

Particulate pollutants

It is a mixture of minute particles and liquid droplets. It comprises components that include acids such as nitrates and sulphates, organic chemicals, metal and dust particles. The toxicity of particulate pollutants depends on their size. Some major particulate pollutants are soot (powder-like substance originating from incomplete burning of coal and charcoal) metal particles that might react with compounds like SO2 and become toxic for humans. Also, asbestos dust is highly poisonous and comes from open-pit mining of asbestos-rich areas. If the asbestos is released in the water bodies or grounds directly, it could also impact the local population in many ways.

Atmospheric ozone 

Atmospheric ozone with the chemical formula of O3 exists in the stratosphere (15-50 km above earth’s surface), and it protects the earth from harmful ultraviolet radiation from the sun. These UV  radiations can cause skin cancer ( known as melanoma) and therefore, we need to maintain the ozone layer. Ozone is produced as a result of the action of ultraviolet radiations on dioxygen.

However, the ozone at the ground level could be harmful. It is created by a chemical reaction between nitrogen oxide and VOC under sunlight.

Industrial facilities, electrical appliances and tools, motor vehicle exhaust, gasoline vapours, and chemical solvents emit ozone and are major NOx and VOC sources.

Example of Atmospheric pollution

Smog = Smoke + Fog

The name suggests that it is a combination of smoke and fog. It is one of the most common examples of air pollution. It is of two types i.e Classical smog and photochemical smog. Classical smog or London smog is a mixture of smoke, fog and sulphur dioxide whereas Photochemical smog or los angeles smog’s main components result from the action of sunlight on unsaturated hydrocarbons and nitrogen oxides produced by automobiles and factories. Photochemical smog has a high concentration of oxidising agents like NO2 .

Smog irritates the nose and throat and their high concentration causes headache, chest pain, dryness of the throat, cough and difficulty in breathing. Both ozone and PAN act as powerful eye irritants.

Effects of atmospheric pollution

Depending on the pollutants and length of exposure, the effect on the human body can differ.

1. Pollutants from burning fossil fuels cause heart ailments that reduce the heart’s ability to pump adequate amounts of oxygen. It also causes respiratory issues.
2. Industrial pollutants harm health depending upon the nature of the pollutant. It could range from basic eye and throat irritation to chronic illnesses like cancer.
3. Smog and soot created because of atmospheric pollution cause respiratory illness lasting from short to long periods. It can cause and intensify asthma in patients. Along with this, this could enter the bloodstream, worsen bronchitis and cause a heart attack.
4. Breathing the gaseous pollutants like methane from decaying garbage carbon and sulfur oxides from industries and fossil fuels may even lead to death. This, along with vehicle emission, is a significant reason for holes in the ozone layer due to which harmful Ultraviolet rays enter the atmosphere.
5. Pesticides and fertilisers with harmful chemicals often get mixed up with water and soil, which also impacts the health of humans and the vegetation around them.
6. Many of the hazardous pollutants can affect human beings’ immune, nervous, endocrine systems, and reproductive health.
7. Greenhouse gases have become a significant area of concern across the countries in the world. It causes climate change, which is responsible for melting glaciers and rising sea levels, extreme weather, increased infections, and climate migration.

Preventive measures

Air pollution can be prevented if we take  few preventive measures such as

1. Using raw materials such as water ,energy etc. efficiently
2. Replacing hazardous  substances from less  harmful ones
3. Use filters for chimneys
4. Avoid usage of crackers
5. Use low sulphur fuels
6. Use of petrol without lead 
7. Use of smokeless chulha
8.  Establishment of industries away from the cities and towns

Conclusion

Atmospheric pollution is a great threat towards existence of humankind as we need oxygen for our survival. Atmospheric pollution  is any undesirable change in physical,chemical and biological properties of atmosphere or contamination due to human activities which make it harmful for living beings.  There is a need to create awareness among people about atmospheric pollution so that it can be prevented . Even government has put restrictions on combustion of fossil fuels and made many laws to protect our environment from pollution.