As a type of eucaryote multicellular insect, fruit flies have similar physiological functions and metabolic systems to that of mammals and are very sensitive to air quality.

According to Li Shuguang, dean of the pre-clinical medicine institute of Shanghai's Tongji University, scientists detected the abnormal reaction of fruit flies to polluted indoor air through an interesting experiment.

In the experiment, five columns were set up in a 10-square meter room newly fit with various finishing materials such as formaldehyde, benzene, ammonia and niton. Each column was marked at 0.5 and 1.7 meters, the general heights where people stand up and lie down. On each point, scientists placed 40 fruit flies to detect the polluted degrees of air.

The result showed that the average lifespan of the 800 fruit flies in the experiment was shortened by half from the normal 50 days to about 25 days. The number of sudden deaths at every test point was almost the same.

"It indicated that the air of the whole room was full of poisonous gases due to unhealthy fittings. People's health would certainly be impaired if they moved into it," Li said.

Li is now embarking on further studies of various biological indicators of fruit flies influenced by the polluted air, hoping to provide clues as to how indoor air pollution harms human bodies.

"Fruit flies are efficient 'scouts' that can detect the indoor air pollution sensitively. Maybe we can develop new products to monitor the indoor air quality by imitating their physiological mechanism," said Li.

Currently, indoor air pollution has been listed one of the top ten threats to human health. Mainly through poisonous substances emitted from unqualified household finishing materials, in China alone the pollution causes a reported annual death toll of 111,000 people.

(Xinhua News Agency February 17, 2003)