What is air pollution?
Air pollution is the presence of harmful gases, dust, and smoke in the atmosphere that causes to effects the health of humans or other living organisms. There are different types of pollutants present in the air in the atmosphere and causes different types of disease and allergies. Ammonia, carbon monoxide, sulfur dioxide, nitrous oxides, methane, carbon dioxide, chlorofluorocarbons, and ozone are the main types of gaseous pollutants that caused air pollution. Both human activities and natural sources can create air pollution in our environment. For solutions to air pollution to get clean air, we need to reduce the emission of such harmful gases in our environment.
Air pollution measurement
The concentration of gaseous pollutants is measured by the unit ppm. ppm is the number of pollutants molecules present in one million molecules of air. For example, if 50 molecules of carbon monoxide are present in one million molecules of air, the concentration of carbon monoxide in air is equal to 50 ppm. Therefore, the ppm value of a given gaseous pollutant indicates that the number of pollutants molecules present in 1000000 molecules of air.
Sources of air pollutants
In this paragraph, we discuss various sources which produce air pollution in the atmosphere.
Burning of coal, wood and oils
When coal, wood, and oils are burnt, it produces black smoke. Back smoke contains poisonous gas like carbon monoxide, sulfur dioxide, and unburnt carbon particles. The smoke is black due to the presence of carbon particles on it. Carbon monoxide, sulfur dioxide, and unburnt carbon particles produced by different types of burning go into the air and make it polluted.
Air pollution caused by vehicles
Air pollution in vehicles is caused by gases released due to the internal combustion of vehicles engines like cars, buses, trucks, airplanes. Now let us see how the pollutants are produced in the vehicles. Petrol, diesel, or gasoline is used as fuel in vehicles engines. The main components of these fuels are hydrocarbons. It burns very fast in vehicles. Due to the short time available for burning, incomplete combustion of fuels takes place. Therefore some CO, unburnt carbon particles, CO2, water vapour, some alcohol, and acids are produced during the burning of fuels. CO, CO2, and carbon particles mixing with air and air get polluted.
When fuels are burnt in an engine, a very high temperature is produced. At high temperatures, nitrogen and oxygen present in the air combine together to form NO and NO2 gas. These gases also pollute the air of our environment. It also mixed with rainy water or moisture to form acid rain or snow.
Air pollution from industries
The chemical industries emit various types of poisonous gases into the air. These gases make the air polluted. For example, an industry producing bleaching powder emits chlorine gas into the air. The industries working for the extraction of metals like iron, copper, and zinc produces SO2 gas which causes air pollution.
Radioactive waste materials
The radioactive waste materials produced during the enrichment of nuclear fuels in nuclear power reactor, hospitals, and laboratories emit high-energy gamma radiation. Radioactive pollution produces some serious diseases like leukemia. The radiation initiates unwanted cell growth which causes cancer.
Air pollution causes and effects
Effects of carbon monoxide on the environment
Before we discuss the toxic effects or air pollution caused by carbon monoxide on the environment or human beings or animals, we need to know about the structure and facts of hemoglobin. It is an octahedral complex of iron (II). The center of the octahedron contains Fe (II) and four corners of the square are occupied by four nitrogen of heme group. The fifth position is occupied by the nitrogen atom of histidine while six position is empty. When human beings or animals inhales oxygen from the environment, oxygen combine with hemoglobin to form an oxy-hemoglobin complex (HbO2). It dissociates in the cells to form hemoglobin and oxygen. Therefore, it is used as an oxygen carrier for humans or animals.
The affinity to gain carbon monoxide is greater for hemoglobin than oxygen. Therefore, if human beings or animals inhale CO instead of oxygen, the vacant position of hemoglobin is occupied by CO to form carboxyhemoglobin. It makes Hb unable to take up oxygen from the lungs and carry it to the cells. Therefore, oxygen available for body cells is reduced. This is called anoxia. It causes suffocation and may even lead to the death of human beings or animals.
Effects of carbon dioxide in the atmosphere
Although a small quantity of carbon dioxide is not usually considered to causes air pollution. But the excess quantity of carbon dioxide in the air causes the greenhouses effect to increases the temperature of the earth’s atmosphere. The trapping of infrared radiations reflected from earth’s surface by the carbon dioxide layer in atmosphere is called greenhouse effect.
If the atmosphere contains too much quantity of carbon dioxide, the greenhouse effect is considerably increased. Therefore, the temperature of the earth is increased too much. It melts all the glaciers to causes floods on lower-lying areas on the earth, changes the biological activities of oceans, and patterns of cropping.
Effects of nitrogen dioxide on human health
Nitrogen dioxide is a toxic gas and it effects human beings, animals, and vegetables in the following ways,
- Nitrogen dioxide in the atmosphere reacts with rainy water or moisture in presence of oxygen or ozone to form nitric acid rain or snow. Nitric acid rain gradually gets up stone and marbles of the buildings and corrodes metals. It fades the color of the fabrics and effects the acidity of lakes.
- Nitrogen dioxide causes extensive leaf drops in plants.
- It reacts with oxygen to produces other pollutants namely ozone.
- It is very corrosive and attracts the skin of human beings. NO2 helps in the formation of smog. Smog in air pollution effects the eyes due to the presence of ozone gas on them.
- It has been shown that if monkey inhales NO2 of 15 to 20 ppm concentration for 2 hours, their lungs, liver, and kidneys are totally damaged.
Effects of sulfur dioxide
Sulfur dioxide presents in the air effects human beings animals and plants in the following ways,
- Sulfur dioxide present in the air undergoes photolytic and catalytic oxidation to form sulfur trioxide. Sulfur trioxide reacts with rainy water or moisture to form sulfuric acid. It comes down to the atmosphere in the form of sulfuric acid rain or snow which is as dangerous as nitric acid rain. It also causes soil pollution and water pollution.
- Sulfur dioxide in the air irritates the respiratory system of human beings or animals.
- If plants get a high concentration of SO2 over a short period, the brownish colour in the tips of pine needles gets decolorized. If plants are exposed to the sulfur dioxide of low concentration over longer periods, the production of chlorophyll in plants is hampered.
- Due to the corrosive nature of SO2 and H2SO4, these air pollutants decolorize the building materials like limestone marbles roof slate, and mortar.
Harmful effects of ozone
Some ozone is produced during the various combustion processes taking place in the air around us. Ozone gas in the air does not cause air pollution. If the concentration is more than 0.1 ppm in air pollution, ozone gas is toxic and causes harmful effects to human beings. Breathing of ground-level ozone gas causes different types of health problems like chest pain, coughing, throat irritation, and congestion. It can reduce lung function and inflame the lining of the lungs.
Effects of dust
Dust in air pollution is produced due to heavy traffic on roads and some industrial operations. Dust in air pollution spoils our clothes and causes poor visibility. It is allergic and causes the diseases like bronchitis. It is deposited on the leaves of plants which hindered the process of photosynthesis.
Effects of smoke on health
Smoke in air pollution is produced during the burning of fuels like coal and oil in homes or factories. The smoke contains unburnt carbon particles which pollute the air of our enviourment. It spoils our clothes, blackens the building and prevents sun rays to reach every corner of our city. Smoke damages our lungs. For solutions, the pollution of air caused by smoke can be prevented by using electrical energy, solar energy, Tindel energy, etc.
Air pollution solutions
We have already discussed that air is polluted by the presence of CO, CO2, NH3, CH4, SO2, O3, unburnt hydrocarbon, dust, smoke, etc. The solutions to control the pollution of air by these pollutants prevented by following methods,
- By adding lead tetraethyl, Pb(C2H5)4 to petrol or by catalytic oxidation of CO and hydrocarbon by the platinum catalyst. Present time lead tetraethyl is avoided due to lead posing. This method can be used to control air pollution caused due to the presence of CO and unburnt hydrocarbon on it.
- By keeping the vehicles properly tuned for the optimum ignition of fuel. It prevents air pollution caused by CO and hydrocarbons present in the exhaust fumes of vehicles.
- By growing more plants. It is the solution to control air pollution caused by carbon dioxide gas.
- For removing carbon particles produced by burning fuels like coal and oil, we used electrostatic precipitators.
- By using smokeless sources of energy or renewable energy. It is used for the prevention of air pollution caused by smoke or carbon particles produced during the burning of oil or coal.
- Using natural gas or liquefied petroleum gas (LPG) in the place of wood or coal for heating or cooking purposes. It saves air from the pollutant like CO2 and SO2.
- The use of tall chimneys in homes and factories for solutions to air pollution at the ground level.