Test : Environmental Issues 4 - From Past 28 Years Questions (Old NCERT)

NO₂ and SO₂ after reacting with water in atmosphere produce HNO₃ & H₂SO₄ which fall down as acid rain.

CO₂ in its normal fraction in air (about 0.03%) is actually  not a pollutant but above this it is considered as a pollutant. At the elevated level it becomes a cause for global waring.

Increase in the concentration of CO₂ do not allow the earth's radiations to go out of earth’s atmosphere and contributes in increasing temperature of earth.

Fluorides of carbon is the major pollutant from jet plane emission.

MIC → (Methyl Isocyanate) was the deadly gas leaked from the fertilizer plant of Union Carbide company in Bhopal.

"Domestic waste" means any non-putrescible waste, consisting of combustible materials, such as paper, cardboard, yard clippings, wood, or similar materials, generated in a dwelling, including the real property upon which it is situated, containing four living units or less. These wastes are biodegradable hence, considered as biodegradable pollution. 

Lead (Pb) is the most hazardous metal pollutant present in automobile exhaust.

Ultraviolet radiation scause photochemical splitting of oxygen molecules in the stratosphere. The nascent oxygen combines with molecular oxygen to form ozone. In troposphere nascent oxygen comes from nitrogen dioxide.

DDT is not soluble in water but soluble in fats. Aquatic micro-organisms absorb them in fats where they accumulate to form concentration many times greater than in water. Zooplankton accumulate more concentrations, fishes feeding on zooplanktons also accumulate more concentration and finally birds feeding on fishes contain these compounds in more concentration. This increase in accumulation of toxic substances in the food pyramids is called "Biological magnification."

CO₂ is the major green house gas causing green house effect which is released in the atmosphere by burning fossil (combustion) or by activities like animal respiration. Deforestation adds to the increase in CO₂ in atmosphere because trees are cut down which are the big absorber of CO₂. 

Minamata disease.

In 1962, American biologist Rachel Carson published the book Silent Spring, which alleged that DDT caused cancer and harmed bird reproduction by thinning egg shells. This followed the principles of biological magnification, killing higher level organisms like the birds.
DDT is a persistent organic pollutant with a reported half life of between 2-15 years, and is immobile in most soils. 

Above 80 dB sound becomes hazardous.

Sewage kills plant life and also use oxygen for degradation, so oxygen content of water is lowered and hence animal life in water body start decreasing. 

The Taj Mahal is threatened by environmental pollution, especially by acid rain due to sulphur dioxide emitted from Mathura refinery.

By dumping of huge amount of sewage, the oxygen levels are depleted, which are reflected in terms of BOD values of water. The number of microbes also increases tremendously and these also consume most of the oxygen. Thus BOD of the river water will increase.

Release of mercur y in water causes pollution. Mercury enters the food chain killing fishes. Human beings feeding on such fishes will suffer from minamata disease. Similarly all carnivores feeding on fishes will develop this disease except rabbit because it is herbivore.

Organic pollutants brought in by the sewage drained into water bodies provides nutrients for stimulating growth of algae. Algal bloom reduces availability of light to the submerged plants which get killed. Dead algae and dead submerged  plants consume oxygen during decomposition, causing oxygen depletion and increases competition for oxygen.

The MIC gas tragedy occurred in Bhopal in 1984 and the Chernobyl tragedy (nuclear power plant) occurred in Ukraine in 1986.

The major contributor of Green House gases to the atmosphere is U.S.A., which itself releases around 37% of the chlorofluorocarbons (CFCs).

Part of fertilizers containing phosphates are passed down into water bodies as surface run off. Sewage contamination  also results in algal bloom (eutrophication) due to increased availability of nitrate and phosphate.

The content of CO₂ in atmospheric air is 0.034%. The main contributors to air are N₂ and O₂.

Increase in air pollution has resulted in gradual depletion of the ozone layer. This  has exposed the earth's surface to the harmful ultraviolet radiations of the sun. Exposure to UV rays increases the risk of skin cancer and other skin related disorders. 

Ozone hole is an area with extreme reduction in the ozone concentration. It was discovered over Halley Bay in Antarctica by Farman et. al (1985), members of British Antarctic Survey Team.
Image of the largest Antarctic ozone hole ever recorded in September 2006.