|
Major air pollutants and their sources
|
|
Carbon monoxide (CO)
|
- Carbon monoxide is a colorless and odorless gas formed during the incomplete combustion of carbon-containing fuels like petrol, diesel, and wood.
- It is also released when both natural and synthetic materials, such as cigarettes, are burned.
- It lowers the amount of oxygen that enters our blood. It can slow our reflexes and make us confused and sleepy.
|
|
Carbon dioxide CO2
|
|
|
Chlorofluorocarbons (CFC)
|
- Gases that are released mainly from air-conditioning systems and refrigeration.
- When released into the air, CFCs rise to the stratosphere, where they come in contact with few other gases, which lead to a reduction of the ozone layer that protects the earth from the harmful ultraviolet rays of the sun.
|
|
Lead
|
- Present in petrol, diesel, lead batteries, paints, hair dye products, etc.
- Affects children in particular.
- Cause nervous system damage and digestive problems and, in some cases, cause cancer.
|
|
Ozone
|
- Occurs naturally in the upper layers of the atmosphere.
- At-the ground level, it is a pollutant with highly toxic effects.
- Vehicles and industries are the major source of ground-level ozone emissions.
- Ozone makes our eyes itch, burn, and water. It lowers our resistance to cold and pneumonia.
|
|
Nitrogen oxide (Nox)
|
- Causes smog and acid rain. It is produced from burning fuels including petrol, diesel, and Coal.
- Nitrogen oxide can make children susceptible to respiratory diseases in winters.
|
|
Suspended particulate matter (SPM)
|
- Consists of solids in the air in the form of smoke, dust, and vapour that can remain suspended for extended periods
- The finer of these particles when breathed in can lodge in our lungs and cause lung damage and respiratory problems.
|
|
Sulphur dioxide (SO2)
|
- A gas produced from burning coal, mainly in thermal power plants.
- Some industrial processes, such as production of paper and smelting of metals, produce sulphur dioxide.
- A major contributor to smog and acid rain.
- Sulphur dioxide can lead to lung diseases
|
|
Smog
|
- A combination of the words fog and smoke. Smog is a condition of fog that had soot or smoke in it.
- Interaction of sunlight with certain chemicals in the atmosphere.
- Primary components of photochemical smog is ozone.
- Oxides, and sunlight. It is formed when pollutants released from gasoline.
- Ozone is formed through a complex reaction involving hydrocarbons, nitrogen diesel- powered vehicles and oil-based solvents react with heat and sunlight from biofuels, the four most serious pollutants are particulates, carbon monoxide, polycyclic organic matter, and formaldehyde.
|
|
Other Pollutants
|
|
Volatile organic compounds
|
- The main indoor sources are perfumes, hair sprays, furniture polish, glues, air fresheners, moth repellents, wood preservatives, and other products.
- Biological pollutants – It includes pollen from plants, mite, and hair from pets, fungi, parasites, and some bacteria.
|
|
Formaldehyde
|
- Mainly from carpets, particle boards, and insulation foam. It causes irritation to the eyes and nose and allergies.
|
|
Radon
|
- It is a gas that is emitted naturally by the soil. Due to modern houses having poor ventilation, it is confined inside the house and causes lung cancers.
|
|
Fly Ash
|
Ash is produced whenever combustion of solid material takes place.
- Aluminium silicate (in large amounts)
- Silicon dioxide (SiO2) and
- Calcium oxide (CaO)
Fly ash particles are oxide rich and consist of silica, alumina, oxides of iron, calcium, and magnesium and toxic heavy metals like lead, arsenic, cobalt, and coppers.
|
|
Policy measures of MoEF (Ministry of Environment,Forest and Climate Change)
|
|
Important measures
|
- The Ministry of Environment and Forests vide its notification in 2009, has made it mandatory to use Fly Ash based products in all construction projects, road embankment works and low lying land filling works within 100 kms radius of Thermal Power Station.
- To use Fly Ash in mine filling activities within a 50 kms radius of Thermal Power Stations.
- Arresters: These are used to separate particulate matters from contaminated air.
- Scrubbers: These are used to clean air for both dusts and gases by passing it through a dry or wet packing material.
|
|
Government Initiatives
|
|
National Air Quality Monitoring Programme
|
- In India, the Central Pollution Control Board (CPCB) has been executing a nationwide programme of ambient air quality monitoring known as National Air Quality Monitoring Programme (NAMP).
|
|
The National Air Quality Monitoring Programme (NAMP) is undertaken in India:
|
- (i) To determine status and trends of ambient air quality.
(ii) to ascertain the compliance of NAAQS.
(iii) to identify non-attainment cities.
(iv) to understand the natural process of cleaning in the atmosphere; and
(v) to undertake preventive and corrective measures.
- Annual average concentration of SOx levels are within the prescribed National Ambient Air Quality Standards (NAAQS).
- National Ambient Air Quality Standards (NAAas) were notified in the year 1982, duly revised in 1994 based on health criteria and land uses.
- The NAAQS have been revisited and revised in November 2009 for 12 pollutants, which include, Sulphur dioxide (S02), nitrogen dioxide (N02), particulate matter having size less than 10 micron.
- (PM 10),particulate matter having size less than 2.5micron (PM2.5), ozone, lead, carbon monoxide (CO), arsenic, nickel, benzene, ammonia, and. Benzopyrene.
|