Test: Air Pollution (NCERT)

Bag filter and scrubber are used to control particulate matter in air pollution.

Electrostatic precipitators (ESPs) are very efficient devices which remove 99 % of particulates present in the industrial and thermal plant exhausts. There are electrode wires and a stage of collecting plates. The collecting plates. The collecting plates wires and a stage of collecting plates. The collecting plates are connected with ground. The electrode wires are provided with several thousand volts electric current. It creates a corona which releases electrons. The electrons attach to the suspended particles and make them negatively charged within a fraction of a second. Air with charged particles passes slowly over collecting plates. The particulate matter settles over them and are removed.

The electrostatic precipitator is used to remove air pollution caused by the factories.So, the correct option is 'A- Negatively charged wire, B- Discharge corona, C- Collection plate, D- Negatively charged dust particles'

Pollens are present in air. Excess of pollen are produced in certain seasons which causes allergic reactions in several human beings. The common allergic reactions are asthma, bronchitis and rhinitis.

Anthropogenic air pollutants are man made pollutants like emissions, burning of fossil fuels, mining, etc. Sulphur dioxide is produced in large quantity during smelting of metallic ores and burning of petroleum and coal in industries and by motor vehicles. It is the cause of acid rain.

The Air (Prevention and Control of Pollution ) Act 1981 deals with the preservation of air quality and the control of air pollution with a concern for the detrimental effects of air. By an amendment in 1987m noise was also recognised as an air pollutant.

Bhopal gas tragedy, the world's worst industrial catastrophe was not due to radioactive fallout, but it was because of leakage of phosgene and methyl isocyanate gas.

CNG produces 45% fewer hydrocarbons than gasoline.
Unleaded petrol doesn't produce lead in the atmosphere.
Catalytic converter reduces emissions of three harmful compounds found in car exhaust which are Carbon monoxide (a poisonous gas) Nitrogen oxides (a cause of smog and acid rain) Hydrocarbons (a cause of smog)

50% carbon monoxide emissions are from automobiles. Normally CO has a brief residence in atmosphere and gets oxidised to CO_². However, in congested and closed areas it proves quite harmful. Carbon monoxide combines with haemoglobin produces carboxyhaemoglobin of COHb. At 50 ppm, CO converts 7.5 % of haemoglobin into carboxyhaemoglobin with 8 hours. It impairs oxygen transport resulting in giddiness, headache, decreased vision, cardiovascular malfunction and asphxia.

Acid rain damages plants by direct effect on foliage and growing point- chlorosis, necrosis, defoliation, dieback. It causes leaching of essential minerals of soil.

The Bhopal disaster or Bhopal gas tragedy was an industrial accident. It happened at a Union Carbide subsidiary pesticide plant in the city of Bhopal, India. On the night of 2-3 December 1984, the plant released approximately 40 tonnes of toxic methyl isocyanate (MIC) gas, exposing more than 500,000 people to toxic gases. The plant in Bhopal where the disaster happened started to produce 'Carbaryl' in 1977. Carbaryl is mainly used as an insecticide. The disaster happened because water entered a tank containing Methyl isocyanate. This caused a chemical reaction which resulted in the buildup of much Carbon dioxide, among other things. The resulting reaction increased the temperature inside the tank to reach over 200 °C (392 °F). The pressure was more than the tank was built to withstand. The tank had valves to control the pressure. These were triggered in an emergency, which reduced the pressure. As a result, large amounts of toxic gases were released into the environment. 

Automobiles burn petroleum inefficiently causing 80% of air pollution and 75% of noise pollution in urban areas. They release hydrocarbons (13.7%), carbon monoxide (77.2%), nitrogen oxides (7.7%), sulphur oxides, ammonia, aldehydes and lead (90% of total lead poisoning). Lead is present in petroleum in the form of Pb(CH₃)₄ and Pb(C₂H₅)₄ as antiknock agent.

Acid rain is caused by large-scale emission of acidic gases into the atmosphere from thermal power plants, industries, and automobiles. The common ones are sulfur dioxide, nitrogen oxides NO_x, volatile organic carbons VOCs and hydrogen chloride. NO_x is also produced in the atmosphere through lightning. Sulfur dioxide and nitrogen oxides are changed in the atmosphere into sulphuric acid and nitric acid by combining with oxygen and water.

Lichens are indicators of air pollution, espedav of the concentration of sulphur dioxide in the atmosphere. Air pollutants dissolved in rain water, mainly sulphur dioxide can damage lichens and prevent them born growing. So, lichens are natural indicators of air pollution. 

Nitrogen oxides are produced naturally through biological and non-biological activities. Human activity forms nitrogen oxides in combustion process of industries, automobiles, incinerators and nitrogen fertillisers. Nitrogen oxides give rise to photochemical smog.

Chlorofluorocarbons are the chemicals whichare used as refrigerants, propellants and solid plastic foams. The chemicals are released as aerosol by jets flying at high altitudes. Along with nitrogen oxides, chlorofluorocarbons react with ozone of ozonosphere and deplete the same.

Peroxyacyl nitrate (PAN) is produced due to reaction between NO_X and hydrocarbons under effect of UV-radiation of sunlight.

Secondary air pollutants are more toxic than primary air pollutants.

Carbon monoxide (CO) is produced due to incomplete combustion of fossil fuels, metallurgical operations, automobile emission, cigarette smoking. CO combines with haemoglobin, produces carboxyhaemoglobin which impairs oxygen transport resulting in headache, decreased vision, cardiovascular disease, asphyxia.

Hiroshima Day is on August.