Antimosquito coils release toxic fumes. (Environment).

In places with nocturnal mosquitoes, many people burn spiral-shaped strips of insecticide-treated plant matter near their beds. These mosquito coils smolder through the night to keep bugs at bay, but they can also cause asthma and wheezing in children. Now, researchers have measured several pollutants in smoke emitted from mosquito coils.

Formaldehyde is one example. A single burning coil can release as much of the carcinogen as can 51 cigarettes, the researchers report in an upcoming Environmental Health Perspectives. Each coil can also emit PM2.5, or airborne particles less than 2.5 micrometers wide, in amounts equivalent to those released by 137 cigarettes. Particles that small can carry toxic compounds deep into the lungs.

Junfeng Zhang of the University of Medicine and Dentistry of New Jersey and Rutgers University in Piscataway, N.J., and his colleagues obtained their data by testing six popular brands of mosquito coils from China and Malaysia. Since the amounts of various pollutants emitted by these brands differ widely, systematic testing of coils could help consumers make informed choices, the researchers suggest.--B.H.