aggravated because of four developments:
Increasing traffic, growing cities, rapid economic development, and industrialization
contamination of air by the discharge of harmful substances
Major air pollutants and their sources
- Carbon monoxide (CO)
- It is a colourless, odourless gas that is produced by the incomplete burning of carbon – based fuels including petrol, diesel, and wood.
- It is also produced from the combustion of natural and synthetic products such as cigarettes.
- It lowers the amount of oxygen that enters our blood. It can slow our reflexes and make us confused and sleepy.
- Carbon dioxide (CO2)
principle greenhouse gas
- Chloroflorocarbons (CFC)
- gases that are released mainly fromair-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 (S02)
- 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.
- Ozone is formed through a complex reaction involving hydrocarbons, nitrogen oxides, and sunlight. It is formed when pollutants released from gasoline, 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
Pollutants
- i) Volatile organic compounds
The main indoor sources are perfumes, hair sprays, furniture polish, glues, air
fresheners, moth repellents, wood preservatives, and other products.
- ii) Biological pollutants
It includes pollen from plants, mite, and hair from pets, fungi, parasites, and some bacteria.
iii) Formaldehyde
Mainly from carpets, particle boards, and insulation foam. It causes irritation to the eyes and nose and allergies.
- iv) 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.
Composition
- Aluminium silicate (in.large amounts)
- silicon dioxide (Si02) and
- Calcium oxide (Ca0).
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:
- 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 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
(1) 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 (NAAQS) 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 (NO2), particulate matter having size less than 10 micron
(PM10),particulate matter having size less than 2.5micron (PM2.5), ozone, lead, carbon monoxide (CO), arsenic, nickel, benzene, ammonia, and. Benzopyrene.
BPCS Notes brings Prelims and Mains programs for BPCS Prelims and BPCS Mains Exam preparation. Various Programs initiated by BPCS Notes are as follows:-