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Pollution & Climate Change — UPSC Prelims Science & Environment previous year questions — page 3

83 solved previous year questions on Pollution & Climate Change, papers from 1993 to 2023, drawn from UPSC CSE Prelims, UPPCS, UPSC CAPF. Each carries the printed answer key and the explanation from the source compilation.

1. #81Full-length test
   Which among the following statements is incorrect about Black carbon and Brown carbon?
   • ABlack Carbon reduces the albedo of the Earth when deposited on snow and ice
   • BBrown Carbon is brown smoke released by the combustion of biomass
   • CBlack Carbon is a long-lived carbon pollutant which, once released, remains in the atmosphere for years
   • DThe absorption capacity of black carbon is almost 50 times more than brown carbon
   Answer: (C) Black Carbon is a long-lived carbon pollutant which, once released, remains in the atmosphere for years
   Explanation

   Option c is the correct a is correct. Black carbon warms the Earth heat in the atmosphere and by reducing to reflect sunlight) when deposited on ice. It is the strongest absorber of sunlight and heats b is correct. Brown Carbon is brown by the combustion of organic matter or It coexists with black carbon when released in Both Black and Brown carbon aid to the and c is incorrect. Black carbon is a pollutant which remains in the atmosphere days to weeks before it descends as rain or snow. (BC) is a component of fine particulate matter (PM 2.5 µm in aerodynamic diameter). It is formed incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and d is correct. A recent study by HT-Kanpur that in terms of mass, brown carbon is 10 than black carbon. The absorption capacity of is 50 times more than brown carbon. It suggests carbon was able to absorb about

2. #82Full-length test
   Which of the following items are the major constituents of Photochemical smog? 1. Volatile organic compounds 2. Stratospheric ozone 3. Nitric oxide 4. Aldehydes 5. Peroxyacetyl nitrate (PAN) 6. Hydrocarbons 7. Sulphur dioxideSelect the correct answer using the code given below
   • A1, 2, 3, 5 and 7 only
   • B2, 3, 4, 5 and 6 only
   • C1, 3, 4, 5 and 6 only
   • D1, 2, 3, 4 and 6 only
   Answer: (C) 1, 3, 4, 5 and 6 only
   Explanation

   Option c is the correct exposed to ultraviolet radiation, N02 goes complex series of reactions with hydrocarbons to components of photochemical smog - a mixture of acid, aldehydes, Peroxyacyl Nitrates (PAN) other secondary pollutants. This formed ozone ozone, not stratospheric smog is also produced when sunlight oxides of nitrogen and at least one volatile (VOC) in the atmosphere. Paints, gasoline cleaning solvents release VOCs into the smog and photochemical smog are two of smog recognised so far. Sulfurous smog, also London smog, develops due to high concentration oxides in the dioxide is the composition of Winter smog smog. Important Tips Ground level Ozone: It is also known as tropospheric ozone; it is a colourless and highly irritating gas that forms just above (up to 2 miles) the Earth's surface. It is a "secondary" pollutant (not directly emitted into the air). It is produced when

3. #83Full-length test
   With reference to the role of Methane as a Greenhouse Gas (GHG), consider the following statements: 1. Rice cultivation is the biggest source of methane emissions. 2. It is a much more potent GHG than CO2. 3. India launched the Global Methane Pledge to reduce anthropogenic methane emissionsHow many of the above given statements are correct?
   • AOnly one
   • BOnly two
   • CAll three
   • DNone
   Answer: (B) Only two
   Explanation

   Option b is the correct Notes commonly known as P-Notes Derivative Instruments that are instruments foreign investors, who want to bet on a market with the domestic securities regulators Statement 1 is incorrect: Participatory notes issued by registered foreign portfolio investors investors who wish to be a part of the Indian without registering themselves with the Exchange Board of 2 is correct: The Securities and Exchange Board has barred and resident Indians from offshore derivative instruments I.e. 3 is correct: In India, investments notes is more in equities than debts

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