Study links air pollution and dense traffic to smaller babies

Babies born to mothers who live in areas with air pollution and dense traffic are more likely to have a low birthweight and smaller head circumference, a large European study has found.

The researchers found that babies were smaller even in areas with relatively low levels of air pollution, well below the limits considered acceptable in European Union guidance.

For every increase of 5 micrograms per cubic metre in exposure to fine particulate matter during pregnancy, the risk of low birthweight rose by 18 per cent.

Although they cannot establish that air pollution is the cause of low birthweight, the authors of the study, published in The Lancet Respiratory Medicine journal, believe the link is strong enough to demand action.

"The widespread exposure of pregnant women worldwide to urban ambient air pollution at similar or even higher concentrations that those assessed in our study provides a clear message to policymakers," said Marie Pedersen of the Centre for Research in Environmental Epidemiology in Barcelona, Spain.

Particulate matter is at the core of China's problems with air quality, which has been linked to hundreds of thousands of premature deaths. In one alert in Beijing this year, levels of PM2.5 fine particles reached 40 times WHO recommended limits.

Low birthweight in babies is a concern because it often predicts poorer health as children and as adults. A small head circumference could indicate problems with neurodevelopment.