A piece of good news for those who cannot give up smoking -- take a lot of vitamin C and you could avert heart and lung diseases caused by cigarette smoke (Nature, Vol 370, No 6489).

A team of German and US scientists successfully tested the hypothesis on hamsters exposed to cigarette smoke. Vitamin C, say researchers, is capable of preventing 90 per cent of the damage caused by cigarette smoke to white blood cells. The damaged white blood cells tend to clump together and stick to the blood vessel walls, causing arteriosclerosis -- the thickening of the arteries -- which can lead to heart and lung diseases.

Meanwhile, a study conducted as a part of a major programme to track the sources of particles in the smog over Los Angeles, has identified cigarette smoke as contributing up to 1.3 per cent of the total particulate matter (New Scientist, Vol 143, No 1939).

According to Glen Cass at the California Institute of Technology, although contribution by cigarette smoke is small, it is one of a half-a-dozen minor sources which account for one-fourth of the city's air pollution.