Air pollution is one of the major issues across the world with counties like India and China take their lead because of their huge population and the excess usage of automobiles. Most of the metro cities like Delhi, Mumbai, Chennai, and Bangalore are being alerted regularly when the air quality depletes overnight. One of the burning issues in cities like Delhi is the airborne diseases because of the higher composition of dust, smog, and fog in the air that we breathe. "Air pollution is the increase in the amount of chemical and harmful particles in the air". This is especially true if the size of the particulate measure smaller than 2.5um. Some of the polluting particles can be carbon monoxide, nitric oxide, lead, arsenic, cyanide, CFCs( Chloro Fluro carbons) and ammonia. Air pollution can lead to asthma, chronic obstructive disorders of lungs such as lung cancer, and tuberculosis. It can even damage the brain,kidneys, cardiac system through poor oxygen supply as a result of lower oxygen levels in the air. They also destroy crops by reducing their growth and yield leading to premature death.
Table Of Contents
2. Causes of air pollution
3. Managing/controlling air pollution
4. Electrostatic precipitation of air
5. Automobile pollution and control
Causes of air pollution
The causes of air pollution can be divided into natural and manmade. This is because, air pollution is not just the result of man`s act but also as a result of natural causes like dust, storms, forest fires, volcanoes releasing a great amount of ash. Manmade causes are pollution caused by industrial and domestic activities, population explosion, deforestation, urbanization, etc. Some of the ways through which air pollution can be caused are.
1. Fuel-burning (coal, wood, fossils, cow dung cakes, kerosene) that releases a lot of carbon which leads to the formation of a poisonous combination entering into the air.
2. Motor vehicles emit exhaust gases which can pollute the air, especially in urban areas.
3. Industries generate a greater amount of Sulphur dioxide, oxides of carbon, asbestos, nitrogen oxide, chlorine, cement, and dust. These are poisonous particulates.
4. A huge amount of Sulphur dioxide and fly-ash is released in the thermal power plants that pollute the air.
5. The radioactive rays are emitted by nuclear power plants.
6. Fertilizers and pesticides resulted by agriculture are another threat for air in addition to the soil pollution.
7. Mining activities will release particulate matter into the air and pollutes it.
8. Excessive cutting of trees( deforestation ) will increase the amount of carbon dioxide in the atmosphere leading to air pollution.
9. Refrigeration, fire exhausting, aerosol sprays use CFCs (chlorofluorocarbons) that causes pollution by depleting the ozone layer.
10. Smoking pollutes the air by emitting carbon monoxide and nicotine.
Managing/controlling air pollution
The government of India has passed a few acts to control pollution like the environmental protection act (1990), environment act (1986). Despite these, the individual responsibility of every citizen is really an issue and this the most important aspect to manage air pollution. Air pollution can be prevented by regulating human activities whenever possible. Although it is difficult to stop industrialization, population explosion, and urbanization, some of the compensatory activities can be developed as follows
1. Limiting the use of motor vehicles and replacing them with pedal cycles, or some eco-friendly engine made vehicles for travelling.
2. Use of hybrid cars and encouraging the use of hydrogen power in them.
3. Planting trees across all the available spaces including vertical tree planting, skyscrapers in major towns and cities.
4. Using electrostatic precipitators, Baghouses, and Particulate scrubbers.
5. Upgrading the industries, factories, and aircraft with quality engines.
6. Encouraging and using renewable sources of energy like wind, water, solar, geothermal and tidal energy.
Electrostatic precipitation of air
There are a few manmade techniques that can help to control particulates in some industrial settings such as thermal power plants, smelters and other industries where there is a substantial amount of release of particulate and gaseous air pollutants. Such pollutants have to be filtered out before releasing them into the atmosphere. There are many methods of removing particulate matter, one of the most popular methods is, electrostatic precipitator method. It is a particulate removing device that removes particles including the dust, smoke, and smog. The equipment uses the technique of air being forced in against an electrostatic charge. The polluted gas released from thermal plants is passed forcefully against a layer of scrubbing liquid to trap the particulate matter. The precipitator has electrode wires with several thousands of volts to release some charged electrons. These electrons get stick to dust particles to ultimately give them a negative charge. As seen in the picture below, dirty air enters into the precipitator where the electrodes become active by electric current. At that time the negatively charged wire will release electrons to bind with particulate that comes and settles on some plates called collection plate. The collecting plates are grounded and attract the charged dust particles to that clean air can pass through the electrostatic precipitator. Precipitators are much effective in the removal of pollutants from the gas, but scrubbers may be vulnerable to corrosion because there is frequent exposure of these with the toxic gases. As per the pollution control board, the released particulate must not be smaller than 2.5 micrometres because smaller sized particulate goes deep into the lungs causing diseases.
Electrostatic precipitator( image from Britannica)
Automobile pollution and control
India is the second-largest producer of automobiles in the world. Two-wheelers are being used predominantly against all other vehicles. Two-wheelers are the major reason for the emission of particulate and gases in our country. This is again a major concern when it comes to urban areas. Luckily, the pollution by automobiles can be completely managed through proper maintenance, using lead-free petrol and diesel, the application of pollution control filters, etc. In recent days, governments have made some regulations to adapt platinum-palladium and rhodium as the catalysts to reduce the emission. When the exhaust passes through this catalytic converter, the hydrocarbons that are unburnt will get converted into carbon dioxide and water. Carbon monoxide and nitric oxide will be changed to carbon dioxide and nitrogen gas, respectively. Supreme Court of India has brought many initiatives by keeping in mind the seriousness of pollution in our capital city-Delhi and some metro cities. In addition to platinum-palladium and rhodium, the Indian government is strongly insisting to adopt compressed natural gas (CNG) from diesel and petrol, this is especially for buses. In the year 2002, all the buses of Delhi were converted to CNG based fuel. This is because petrol or diesel emits a large amount of smoke which has a lot of unburnt hydrocarbons. CNG is an effective way to curb the pollution because they release the least smoke and most of the hydrocarbons are completely burnt. On the other hand, CNG is much cheaper than petrol or diesel. Apart from CNG, our government has encouraged the use of unleaded petrol, low-sulfur petrol, diesel. There are also some measures where every vehicle must undergo, a regular emission testing policy. The owners of vehicles emitting solid, black emission are penalized. There is a scale that allows a maximum sulfur at 350 parts-per-million (ppm) in diesel and 150 ppm in petrol, anything excess is subjected to further action by the department of traffic control.