THE damage air pollution does to children鈥檚 health may begin even before birth. Developing fetuses are very susceptible to the harmful effects of some pollutants, a study in New York city suggests.
鈥淭his is yet more evidence that the fetal period is an exquisitely sensitive time in development, and environmental policies should reflect these facts,鈥� says Frederica Perera of the Columbia Center for Children鈥檚 Environmental Health in New York.
There has long been concern about the health effects of the polycyclic aromatic hydrocarbons (PAHs) from vehicle exhausts and power plants. The chemicals, which can coat particulate pollution or exist in vapour form, are highly carcinogenic.
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Nearly a decade ago, Perera鈥檚 team found high levels of DNA damage caused by PAHs in newborns (快猫短视频, 19 October 1996, p 4). But the study, which tested blood from umbilical cords, was done in the highly polluted city of Krakow in Poland, where PAH levels were 30 times those of most western cities. Would the results hold for much cleaner air, and for people from different ethnic groups?
Perera鈥檚 group has now analysed white blood cells from 265 African-American and Latina mothers and their newborn infants, taken in New York between 1997 and 2001. Animal studies suggest the placenta filters out 90 per cent of PAHs, but they found equal levels of PAH-induced DNA damage in both mothers and infants (Environmental Health Perspectives, DOI: 10.1289/ehp.7065). This means fetuses must be 10 times as vulnerable to PAH damage as adults, Perera says. 鈥淲hat gets across is not detoxified, and the damage to the DNA is not repaired in the fetus as it is in the mother.鈥�
Animal studies also suggest that particulates can cause mutations in DNA (快猫短视频, 22 May, p 19). However, it remains to be seen if exposure to PAHs in the womb increases the risk of cancer later in life. 鈥淚 don鈥檛 think we can say yet,鈥� says Roberto Bertollini of the World Health Organization鈥檚 European office.
He says there is some evidence that particulates also affect fetal growth, and that air pollution may have other small but widespread effects on health. Although PAH levels are falling in most western cities, thanks to cleaner car exhausts, for instance, Bertollini thinks more could be done.