Which of the following are the reasons/factors for exposure to benzene pollution? Select the correct answer using the code given below:

Answer: (a) 1, 2 and 3 only

Exhaust, tobacco smoke and wood burning — the combustion sources — are the accepted answer.

Statement by statement

1. ✓ YES Vehicle exhaust (petrol) is a major benzene source.

2. ✓ YES Tobacco smoke contains benzene.

3. ✓ YES Burning wood releases benzene.

4. ✗ NOT ACCEPTED Varnished furniture gives off various VOCs, but UPSC did not count it as a benzene source.

5. ✗ NOT ACCEPTED Polyurethane products are not listed as a benzene exposure source.

The idea

Benzene is a small ring-shaped hydrocarbon. It is present in crude oil and petrol, and it also forms whenever organic material burns without enough air. So think of benzene as a smoke and fuel pollutant: exhaust, cigarettes, wood fires.

Petrol contains benzene → Some escapes at fuel pumps and from exhaust → Burning tobacco or wood also forms it → Breathed in → Long exposure damages bone marrow → leukaemia

Why the others are wrong

(d) Counts varnish and polyurethane, which the key does not.

The trap

Varnish and foam “smell of chemicals”, so (d) feels safe. The key keeps only burning sources.

Also know

Benzene is one of the 12 pollutants in India’s national air quality standards. Fuel rules limit benzene in petrol to 1%. Paints, varnishes and new furniture give off other vapours, mainly formaldehyde, toluene and xylene.