Long-term exposure to traffic-related pollution may significantly increase the risk of asthma in early childhood, a study has warned. The findings, published in the Journal of Allergy and Clinical Immunology, showed that living close to a major road was linked to childhood asthma at all ages examined.

"Children living less than 100 metres from a major road had nearly three times the odds of current asthma - children who either experience asthma symptoms or use asthma medications daily - by ages seven to 10, compared with children living more than 400 metres away from a major road," said study co-author Mary Rice from the Beth Israel Deaconess Medical Center (BIDMC) in Boston, US.