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:

The correct answer is D, 1, 2, 3, 4 and 5. All five release benzene, either by burning carbon-based material or by giving off fumes from solvents and synthetic materials.

Benzene is a volatile organic compound and a known human carcinogen linked to leukaemia. It is a natural part of petrol, so vehicle exhaust and fuel vapour are the largest outdoor sources. Incomplete burning of organic matter produces it too, which is why tobacco smoke, a major indoor source, and wood fires both contain it. Indoors, varnishes, paints, glues and polyurethane foams and finishes slowly release benzene and similar compounds, a process called off-gassing, so freshly finished furniture and foam products add to the load.

A is wrong: it leaves out varnished furniture and polyurethane products, which are indoor sources.

B is wrong: it leaves out vehicle exhaust, the biggest source of all.

C is wrong: it leaves out tobacco smoke and polyurethane products.

Exam tip: benzene = petrol and exhaust outdoors, cigarette smoke plus varnish, paint and foam off-gassing indoors; it is a carcinogen linked to leukaemia.