London - Air pollution significantly raises the risk of babies dying in their first year, a major study has found.
A project tracking nearly eight million infants born in England and Wales found that exposure to chemicals in the air drove up the risk of death by up to 50 percent.
The sooty particulates and nitrogen dioxide pumped out by traffic and sulphur dioxide from industrial emissions are each linked to an increase in risk, researchers from Cardiff University found.
Experts have long warned that air pollution poses a risk to health. But the new research, to be presented at the European Respiratory Society International Congress in Madrid on Sunday, contains some of the starkest findings yet of the extent of that harm.
The study found that three air pollutants – particulate matter known as PM10, nitrogen dioxide and sulphur dioxide – separately and in combination are associated with a 20 to 50 percent increased risk of death for babies born in the most polluted areas.
Dr Sarah Kotecha, from the Cardiff school of medicine, will tell the congress: "We found that NO2, PM10 and SO2 are each linked in varying degrees to infant deaths from any cause, and to neonatal and post-neonatal deaths. This is an important finding as the pollutants are produced and derived from different sources."
Dr Kotecha and her colleagues analysed data from 7.98 million births in England and Wales between 2001 and 2012, obtained from the Office for National Statistics.
They divided the country into around 35 000 similarly populated areas. The most polluted ones saw between 20 to 40 percent higher death rates among infants aged up to one year, 20 to 40 percent higher risks of deaths within 28 days of birth and 30 to 50 percent for post-neonatal deaths between 28 days and a year.
Dr Kotecha said: "Our findings show that although progress has been made, the challenge remains to reduce air pollution in order to reduce the numbers of infant deaths."
A second study, also to be presented to the conference, will show that exposure to traffic pollution in the womb is linked to a reduction in lung function at the age of eight.
Professor Anna Hansell of the University of Leicester, who led that study, said: "Our findings suggest that air pollution in pregnancy and early life has important impacts on lung function in early childhood..."
Dr Penny Woods, chief executive of the British Lung Foundation, said the studies "add to the ever-growing body of evidence showing the terrible harm air pollution is doing to our country’s lungs".