Expectant mothers, who live in cities, are 30 percent more likely to give birth prematurely because of air pollution, a Californian-based study has claimed.
Researchers from the University of California looked at 100,000 births registered within a five-mile radius of air quality monitoring stations in the state, from 22 months starting in June 2004.
They used information provided by the California Department of Health about the babies and their mothers together with air pollution levels.
The results revealed that overall exposure to “critical” pollutants like polycyclic aromatic hydrocarbons (PAH) led to a 30 percent increased risk of giving birth prematurely.
Other toxic substances, such as benzene and fine particulate matter from diesel fumes were associated with a 10 percent increase, while ammonium nitrate fine particles were associated with a 21 percent increase in premature birth.
The researchers also found that the air was more polluted in winter than summer in coastal areas, indicating that local weather patterns played an important part in the dispersal of pollutants.
“Air pollution is known to be associated with low birth weight and premature birth,” said Dr Beate Ritz.
“Our results show that traffic-related PAH are of special concern as pollutants, and that PAH sources besides traffic contributed to premature birth. The increase in premature birth risk due to ammonium nitrate particles suggests secondary pollutants are also negatively impacting the health of unborn babies.
“To reduce the effects of these pollutants on public health, it is important that accurate modeling of local and regional spatial and temporal air pollution be incorporated into pollution policies,” he added.
The results are published in Environmental Health.