Envis Centre, Ministry of Environment & Forest, Govt. of India

Printed Date: Thursday, December 14, 2017

Pollutants & Sources

 

 

Air Pollution offers is in a number of ways. It damages public properly, reduces productivity both industrial and agricultural and causes long term bio-geochemical changes.  Smaller particulates (below 10 µm) in diameter (Pm10) can easily penetrate the lungs and cause respiratory and cardio vascular problems. Ozone may cause asthma, eye irritation and heart disease. Lead and other bio-accumulative pollutants can cause severe damage to the nervous system and the brain. Carbon monoxide reduces the oxygen carrying capacity of the blood.

  

 

Common atmospheric pollution sources and their pollutants

 

Category

Source

Emitting pollutants

Agriculture

Open burning

Suspended particulate matter, carbon monoxide, volatile organic compounds

Mining and quarrying

Coal mining; crude oil and gas production; stone quarrying

Suspended particulate matter, sulphur dioxide, oxides of nitrogen, volatile organic compounds

Power generation

Electricity; gas; steam

Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, sulphur trioxide, lead

Transport

Combustion engines

Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead

Community service

Municipal incinerators

Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead

 

 

SOURCES OF ATMOSPHERIC POLLUTANTS

 

DUSTS

 

The atmosphere contains dust even in the absence of human activity. Meteoric dust from outer space settles at the earth at rate of about 1,000 tonnes/year. However, this amount is exceedingly small compared to other sources. Volcanic eruptions and dust storms can contribute large amounts of dust to the earth’ atmosphere. It has been estimated that the volume of fine ash thrown into the atmosphere by a strong volcanic eruption amounts to as much as 100 billion cu yd. 
The dust in the atmosphere has a wide range of chemical composition. The composition of dust from natural sources varies as the various portions of the earth’s crust.

 

CONDENSATION NUCLEI

 

Vapours in general must be greatly supersaturated before condensation can occur in the absence of foreign particles. A supersaturation of about 4.2 times is required for water vapour. However, whenthe vapour contains particles which can act as nuclei for condensation, little supersaturation is required. Condensation nuclei are important because of the way in which they affect our everyday life. They are largely responsible for fogs and rain. Without them, condensation would occur mainly on the walls of buildings and other exposed surfaces of the earth.

 

BIOLOGICAL AEROSOLS

 

Aerosols of biological origin are probably not important in direct chemical reaction that may occur in the atmosphere. However, the study of aerobiology has provided information that may be important as it applies to the transport of other materials in the atmosphere.

 

GASEOUS IMPURITIES

 

A large number of gaseous impurities is emitted into the air.  The concentrations of impurities can range from practically zero to about 100 percent at the sources. Furthermore, the variety of gaseous impurities is enormous. Howerver, there are a few gases and classes of gases which seem to deserve special attention because of their prevalence in the atmospheres of many industrial cities:

  • Sulphur Dioxide
  • Hydrogen Sulphide
  • Oxides of Nitrogen
  • Ammonia
  • Hydrogen Fluoride
  • Hydrocarbons
  • Aldehydes and Ketones
  • Organic Acids
  • Organic Halides
  • Carbon Monoxide

What you can do to reduce air pollution?

 

  • Encourage your family to walk to the neighborhood market.
  • Whenever possible take your bicycle.
  • As far as possible use public forms of transport.]
  • Don't let your father drop you to school, take the school bus.
  • Encourage your family to form a car pool to office and back.
  • Reduce the use of aerosols in the household.
  • Look after the trees in your neighborhood.
  • Begin a tree-watch group to ensure that they are well tended and cared for.
  • Switch-off all the lights and fans when not required.
  • If possible share your room with others when the air conditioner, cooler or fan is on.
  • Do not burn leaves in your garden, put them in a compost pit.
  • Make sure that the pollution check for your family car is done at regular intervals.
  • Cars should, as far as possible, be fitted with catalytic converters.
  • Use only unleaded petrol.