Which of the following are the reasons/factors for exposure to benzene pollution? 1. Automobile exhaust 2. Tobacco smoke 3. Wood burning 4. Using varnished wooden furniture 5. Using products made of polyurethane Select the correct answer using the code given below:

Answer: A. Sources of benzene exposure include AUTOMOBILE EXHAUST (1), TOBACCO SMOKE (2) and WOOD BURNING (3). Varnished furniture and polyurethane are not significant benzene sources. BENZENE (C6H6) is an AROMATIC HYDROCARBON that is highly volatile, carcinogenic (Group 1 by IARC), and a major component of crude oil and petrol. Chronic exposure is linked to LEUKAEMIA, especially acute myeloid leukaemia, and to bone marrow suppression and aplastic anaemia. SOURCES OF BENZENE EXPOSURE in the environment and indoor air: (1) AUTOMOBILE EXHAUST: CORRECT. PETROL CONTAINS BENZENE (a few percent) as a natural component of refined gasoline and as an octane booster. Vehicular exhaust and EVAPORATIVE EMISSIONS AT FUEL STATIONS release benzene into the air. The CPCB caps benzene in petrol at 1 percent in Indian standards (BS-VI). Urban areas with heavy traffic have elevated benzene concentrations. (2) TOBACCO SMOKE: CORRECT. Cigarette smoke contains BENZENE at high concentrations. ACTIVE AND SECONDHAND SMOKERS face significant benzene exposure. Tobacco is the single largest source of benzene exposure for smokers and people in their environment. (3) WOOD BURNING: CORRECT. INCOMPLETE COMBUSTION OF BIOMASS (wood, agricultural residues, charcoal) releases benzene, polycyclic aromatic hydrocarbons (PAHs), and other volatile organic compounds. Indoor cooking with wood-fired chulhas in poorly ventilated homes (a major issue in rural India) creates significant benzene exposure for women and children. The Pradhan Mantri Ujjwala Yojana addresses this by promoting LPG. (4) VARNISHED WOODEN FURNITURE: WRONG. Modern wood finishes contain VOCs but not significantly benzene. Furniture-related indoor pollutants are primarily FORMALDEHYDE (from particleboard adhesives), toluene, xylene, and acetone, not benzene per se. (5) POLYURETHANE PRODUCTS: WRONG. Polyurethane products release ISOCYANATES (during manufacture), formaldehyde, and other VOCs, but benzene is not the characteristic emission. UPSC marks this as not a significant benzene source. So 1, 2, 3 are the principal benzene exposure routes; 4 and 5 are not. Source: CPCB Indian Air Quality Standards; WHO Indoor Air Quality Guidelines; IARC Monographs on benzene; Ministry of Health pollution reports.