Atmospheric Chemistry

Atmospheric chemistry is that branch of chemistry that deals with chemical composition and reactions of the atmosphere and gives information on the effects of those compositions on the survival of living organisms on the planet. 

Atmospheric chemistry deals with the atmosphere of the planets. The atmosphere of a planet is important in many ways, the interaction between the living organisms and the atmosphere. The ecosystem which is created on the earth is also one of the results of the atmosphere. The atmosphere also deals with problems such as ozone depletion, acid rain, and other hazards of the chemical reactions taking place in the atmosphere.

Thus, in this regard, the chemistry of acid rain and ozone depletion are studied under the scope of atmospheric chemistry. The results and the outcomes of the atmosphere on living organisms and others are also part of atmospheric chemistry.

Earth’s Atmosphere

The earth’s atmosphere comprises different layers as the distance increases from ground level. The different layers of earth’s atmosphere are as follows:

• Troposphere

The first layer of the atmosphere is the troposphere. It mainly starts from ground and can range up to 11 km above ground. The main gaseous components of the troposphere include nitrogen, carbon dioxide, water molecules, and oxygen.

• Stratosphere

The second layer after troposphere is exosphere where it starts from a range of 11 km to 50 km from ground level. The ozone layer is the main composition of the stratosphere, and it can range up to 15 km. 

• Mesosphere

The next layer in the atmosphere is mesosphere which starts from 50 km and goes to 90 km above the ground. The layer is mainly accountable for ionosphere, and therefore, ions of gases are present here such as O2+ , NO+ and other ions as well.

• Thermosphere

The thermosphere is the second last layer of atmosphere and it ranges from 90 km to 500 km. Some ions which are present in the ionosphere region travel to the thermosphere too.

• Exosphere

The exosphere is the last layer of the earth’s atmosphere, and thus it can be referred to as the external or outer space. It mainly consists of hydrogen gas, and the temperature of the exosphere is very high as compared to other layers.

Gaseous Composition

The atmosphere of the earth comprises of numbers of gases and some of these gases are the causes for the effects of climatic change such as global warming, acid rain, and ozone depletion. The atmosphere is a mixture of gases in different proportions. The primary composition of gases are as follows:

• Nitrogen

The nitrogen gas is the most abundant gas which is present in the atmosphere. The proportion of nitrogen gas in the atmosphere is around 78.04%. It is one of the major gases that leads to the harmful effect of acid rain on living organisms. It reacts with oxygen and forms nitrogen oxide which is hazardous to the nature and the living organisms on the earth.

• Oxygen

The second most abundant gas present in the atmosphere is oxygen which is around 20.94% in the atmosphere. Oxygen is the lifeline of living organisms and due to the presence of oxygen, life sustains on the planet.

• Argon

The third abundant gas present in the atmosphere is argon which is around 0.93% in the earth’s atmosphere.

The other gases comprise carbon dioxide, methane, neon, hydrogen, and others. They are present in small proportions in the atmosphere. The gases are constantly being added up to the atmosphere, and their chemical reactions are causing a threat to the living organisms on the earth. The by-products of the reactions between the gases are hazardous to nature and make it difficult to sustain life on the planet.

Reactions of Atmosphere

The gases present in the atmosphere result in a harmful impact on living organisms and causes harm to mankind. The reactions and the result of these reactions are as follows:

•  Acid Rain

When the combustion of fuels takes place from the vehicles and industries, then harmful gases like sulphur dioxide emit into the atmosphere. These gases rise up and react with water vapour present in the atmosphere, which further forms sulphuric acid, and when it rains, it rains in the form of acid rain. Acid rain is mainly caused due to the emissions of harmful gases from vehicles and industries into the atmosphere directly.

•  Ozone Depletion

The release of chlorine and bromine in gaseous form from the industry, especially refrigeration, goes into the atmosphere and reaches up to the ozone layer. Thus, it causes the thinning of the ozone layer particularly over the region of Antarctica. The chlorofluorocarbons are the main causes for the depletion of the ozone layer. With the depletion of the ozone layer, the harmful ultraviolet rays come directly into the troposphere, thus causing harm to living organisms in the form of skin allergies.

Conclusion

Atmospheric chemistry is that branch of chemistry or science that deals with the chemistry of the atmosphere. It gives a brief idea about the chemical composition of the atmosphere of the earth. The reactions taking place in the atmosphere in different layers are described by atmospheric chemistry. The harmful effects of the reactions air pollution, acid rain, global warming and many others are well explained by atmospheric chemistry. 

The atmosphere is a blanket of different layers which are troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The gaseous constituents of these layers of atmosphere depend on the temperature of the layer. The exosphere has the highest temperature and it is considered to be outer space as it is far away from the earth’s troposphere. The harmful effects of these gases and their proportions in the atmosphere varies.