Air Pollution and Its Control
* An undesirable change in the physical, chemical or biological characteristics of air, water, land or soil that may have detrimental effects on living organisms is called pollution.
* Substances that bring about such undesirable changes are called pollutants.
* Common air pollutants are automobile exhausts, chemicals and toxic gases from industries and natural particulate matter such as dust, pollen and ash.
* The usage of CNG, unleaded and low- sulphur petrol and diesel, catalytic converters and the implementation of stringent pollution level norms can reduce air pollution.
* Noise is also considered as an air pollutant.
* Green House Effect and Global Warming
* The greenhouse effect is the heating of the earth’s surface due to greenhouse gases such as carbon dioxide, methane, nitrous oxide and ozone.
* Continuous heating of the earth due to the greenhouse effect has resulted in global warming.
* The rise in the earth’s temperature is resulting of odd climatic changes such as the EI Nino effect and melting of polar and mountain ice caps.
* The melting of glacier and snow caps will result in a rise in sea level, which could submerge many coastal areas.
* A reduction in the use of fossil fuels and deforestation can help reduce global warming.
* Optimal utilisation of energy and planting trees can reduce greenhouse gases.
Ozone Depletion
* Ozone is found in low concentrations throughout the earth’s atmosphere but its highest concentration is found in the lower portion of the stratosphere, where it forms the ozone layer.
* The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in Dobson units.
* In the troposphere, ozone acts as an air pollutant while in the stratosphere, ozone serves as a protective layer.
* The ozone layer is depleting due to CFCs, which are mainly used as refrigerants in air- conditioners, refrigerants and aerosol products.
* A thin layer of ozone, known as an ozone hole, exists over the Antarctic and Arctic regions.
* There are 196 nations who have signed the Montreal Protocol to limit their production of CFCs.
Preventing Different Types of Pollution
Water pollution can be prevented by:
* Treating domestic sewage and industrial waste in treatment plants before releasing them into water bodies.
* Prohibiting activities like washing and bathing in lakes, canals and rivers.
Soil pollution can be prevented by:
* Using organic manure
* Recycling waste paper, glass, plastic and metal
* Trees help to reduce water, soil, air and sound pollution. Hence plantation activities must be encouraged.
Air pollution can be reduced by using:
* Electrostatic precipitators and scrubbers in factories
* Solar cookers, biogas and smokeless chulhas at homes
* CNG, catalytic converters, unleaded petrol and bio – fuel in vehicles
* Public transport in big towns and cities
* Using televisions and tape recorders at low volume and minimal honking while driving can prevent sound pollution