What is air pollution definition in environmental chemistry?

Air pollution is a burning problem in the whole world today. If the density of solid waste or unwanted matter in the air exceeds the normal ratio due to various natural and man-made causes, then this type of air is called polluted air and this process is called air pollution.

If excessive amounts of gaseous substance that are harmful to life and the environment, are increases in the air, then this type of air are called polluted air.

Air pollution is most harmful for human civilization and this problem causes the most damage at the fastest rate.

The air polluting substance damages the life circle of the living world and also destroys the quality of a wide area.

What are the sources of air pollution in environmental chemistry?

The presence of different gaseous substance such as, CO, NO, NO₂, SO₂, CO₂, H₂S, NH₃, CH₄, dust particle, smoke etc in the air are the causes of air pollution.

There are different sources from which these gaseous substances enter into the air and create air pollution. The entire sources are divided into categories.

Air pollution due to natural cause and
Air pollution due to man-made causes

Air pollution due to natural cause

There are few natural causes of air pollution. These are discussed below.

The gaseous substances SO₂, H₂S, CO etc emit due to volcanic eruption and enter into the atmosphere that pollutes air.

The gaseous matter those are produced from the decomposition of the organism and directly enter into the air.

A huge extent of dust particle from forest fire and dust storm enter the atmosphere that causes of air pollution.

Also, virus, bacteria, yeast, flower pollen etc enter the atmosphere and pollute air.

Air pollution due to man-made causes

The man-made causes of pollution are most responsible for air pollution. Most of the pollutants are created due to any type of human activity.

The sources of all type of pollutants those are responsible for air pollution, are discussed below.

The gaseous pollutants such as CO, CO₂ and fly ash those emit from thermal power station and mixed with air.

The various acid vapor (SO₂, NO, HCl, CS₂) and acidic gaseous matter that are used as raw material, emit from acid production industry. These pollutants enter the atmosphere and pollute air.

The gaseous substance that emits from ammonia production industry and also from the usable space, these enters the atmosphere and pollutes air.

The gases such as, SO₂, CO etc and fine dust particle that emit at the time of heat oxidation, calcinations or crushing process of metal extractions.

Also, the gaseous substances due to combustion of fossil fuel enter the atmosphere and pollute air.

The various gaseous oxides such as, CO, CO₂, SO₂, NO₂ etc emit with smoke from motor vehicles, industries and household fuel that enter the atmosphere directly and pollute air.

The fine and coarse solid particle from cement and asbestos industry and also dust particle from mining area enter into the air and pollute it.

The different pollutants such as, CO, NOx, SO₂, Pb etc that emit from petroleum refineries and oil powered motor vehicles are mixed with air directly and pollute it.

Different poisonous gases that emit from the chemical weapons of mass destruction enter the atmosphere and pollute air.

Also the gaseous substance such as, CO₂, CO, SO₂, NO₂ etc those are produced from nuclear power station, thermal power station enter the atmosphere. This is the other causes of air pollution.

What are the harmful effects of air pollution on environment?

Carbon monoxide

Carbon monoxide is a primary contaminant. It is an intense Lewis alkali and also a strong field ligand.

As a result, CO forms permanent complex compound carboxy hemoglobin combines with hemoglobin in the blood which is more stable than the compounds formed by CO2 or O2.

This causes the blood to clot and the oxygen supply to the cells is disrupted or stopped. Normally, animals die due to lack of oxygen in the blood.

Symptoms of nausea, dizziness, etc. are seen in the presence of a small amount of carbon monoxide.

Due to the presence of carbon monoxide in cigarette smoke, smokers suffer from headaches due to the high amount of CO in their blood.

Sulfur dioxide

Sulfur dioxide is a primary contaminant. It plays a major role in the preparation of sulfuric acid. Sulfur dioxide is a highly harmful substance in both the environment and the living world.

This gas combines with water vapor of atmosphere and forms sulfuric acid.

The oxidants present in the air also produce sulfuric acid in conjunction with water vapor after being oxidized by oxygen.

This acid mixed with rain water and falls on the earth in the form of acid rain that damages the environment and the plant world. It also erodes monuments made of marble.

The presence of sulfur dioxide causes inflammation and irritation of the lining of the eyes and various parts of the respiratory tract.

Its effects include bronchitis, respiratory distress, asthma etc. Sulfur dioxide plays a major role in creating fog. This results in smog damage in the presence of sulfur dioxide in the air.

The effect of sulfur dioxide is that the normal growth of the plant is reduced and the leaves become dry. This disrupts photosynthesis.

Chlorine

In the absence of rigid precautions, chlorine is liable to escape into the atmosphere from the sites of industrial units manufacturing paper, plastics, dyes, chlorinated hydrocarbons and other chloro chemicals.

There is also a possibility of accidental leakage in storage tanks and pipe lines.

Chlorine has a sharp irritating odor and is poisonous when inhaled in larger quantity, the maximum allowable exposure being 1 ppm for 8 hours.

Oxides of nitrogen (NOx)

Among the oxides of nitrogen NO and NO2 are act mainly as air pollutant. Nitric oxide does not directly harm human health. But its impact on the environment is greater.

This creates secondary pollutant PAN and Photochemical smog in the presence of a few other elements and sunlight in the environment.

The effects of photochemical fumes irritate the eyes, nose and cause shortness of breath. If this fog persists, there is a possibility of death.

In addition, its presence disrupts the photosynthesis process in plants. As NO2 is a gas of acidic nature, it dissolves in rain water and causes acid rain.

The Lewis alkalinity of NO causes some disruption in the circulation of oxygen through the blood.

Hydrogen sulfide (H₂S)

As the sulfide ion is a soft base, H2S easily forms a stable metallic sulfide in contact with low electrolytic metals.

For this reason, the metallic copper used for electric current easily converts to metallic sulfide in humid air and interferes with the conduction of electricity.

In addition, fancy items made of metallic silver and nickel turn black by forming sulfide salts on contact with H2S.

H2S being a gas of acidic nature causes architectural erosion in the presence of humid air.H2S is a toxic gas. Its effects on humans are deadly. As a result, it causes headaches, nausea, and sore eyes.

H2S can also cause anorexia, diarrhea, and bronchial pneumonia. Toxicity is caused by the reaction of H2S with essential proteins present in the human body.

Gaseous hydrocarbon

The oxides of nitrogen and oxygen those present in the atmosphere react with hydrocarbon in presence of sunlight and form photo-chemical smog.

This photochemical haze causes eye and nose irritation and shortness of breath. Polycyclic aromatic hydrocarbons are carcinogenicsubstances that can cause cancer. Methane gas also has a green house effect

Suspended particulate matter

The aerosol formed by the diffusion medium in the air as a fine phase of solid or liquid particles with a diameter of 0.002µ to 500µ microns is generally called floating contaminant particles.

These particles stay in the atmosphere for a few seconds to a few months. These particles can be of two types, organic and inorganic. These particles are, smoke, dust, smog, fog etc.

Smoke

The smoke produced by incomplete combustion of fuel contains particles of 0.05-0.1 diameter. Its position in the atmosphere lasts for a few days.

Dust

Particles with a diameter of 1µ to 100µ are mixed in the atmosphere during stone crushing, cement factories, dust storms, and when the Haskin machine is running.

However, their location in the atmosphere due to short times duration. These are called dust.

Mist

Some vapors and gaseous substances condense in the atmosphere to form liquid particles or fog with a diameter of 10 microns.

For example, sulfur dioxide gas condenses into sulfur trioxide liquid particles.

Spray

Liquid perfumes, liquid pesticides, dyes are used to make them into fine particles and spraying in the air is called spray. Their position is long lasting in the air.

Fume

Condensation of liquids in the air, fermentation or heating of any organic matter causes fumes.

Fly-ash

During the burning of coal, tiny solid particles mix with the smoke from the thermal power plant into the air. They are called fly-ash. Fly-ash can extend far from the source.

Particles smaller than 5 micron enter the alveoli of the lungs through the nostrils and damage the lungs.

As a result, asbestos workers in asbestos factory, beriliosis in the lungs of beryllium extraction workers, silicosis in cement factory are seen.

The lungs are also affected by black particles in coal mines and white fibers in textiles.

Aerosols, which are soluble in the blood or react with blood components, infect the blood and disrupt its normal functioning.

When floating matter particles accumulate on the leaves of plants over time, the mouth of the stomata closes and photosynthesis is disrupted. The fog created for the aerosol causes a lack of sunlight.

Prevention of air pollution in environmental chemistry

Based on the different aspects of air pollution, two methods can be adopted to decontaminate the air.

In the first case the raw material used is used after separating the cause of the air bubble present.

As a result, there is no possibility of air pollution or the tendency to generate air pollution is reduced.

In the second cases, various technologies are used to remove the pollutants from the air. By taking these two measures, it is possible to get rid of a lot of pollution in the air.

In the first case, the following measures have to be taken to decontaminate the air. Sulfur must be released from coal or mineral oil before being used in combustion.

In case of gaseous fuels, sulfur dioxide present in the fuel should be used after release.

Before the gas emitted from the vehicle is released into the atmosphere, it must be sent to a catalytic converter in the presence of a platinum catalyst to convert the contaminant NOx to nitrogen.

Fine carbon particles must also be removed using state-of-the-art filters before the gas emitted from the vehicle mixes with the air.

Many times the more harmful gas converts CO into less harmful CO₂ and the gas emitted by the motor vehicle is mixed into the air.

In this oxidation process, the organic compounds present in the exhaust gas of the vehicle are also oxidized and converted to CO₂.

Gaseous contaminants dissolved in water are dissolved by water scrubber.

In the second case, the following measures can be taken to decontaminate the air.An electrostatic precipitator is used to release fine floating dust in the air.

The air used in various industries is decontaminated by removing the harmful gases by using absorbers or filters.

Planting trees is the most effective process to prevent air pollution. This is because on the one hand it removes dust and polluted gaseous elements floating in the air and on the other hand there is a possibility of natural rain.