Washington, July 24 - Children of stressed parents are more likely to develop asthma triggered by air pollution, says a new study.

Researchers found that stress and low parental education were also linked with larger effects of exposure to tobacco smoke during pregnancy.

The study was led by Rob McConnell, professor at the University of Southern California (USC).

McConnell said that 'we found that it was children exposed to the combination of air pollution and life in a stressful environment who were at highest risk of developing asthma'.

Asthma is the most common chronic illness among children in developed countries, and a number of studies have linked it to environmental factors, including stress and

socio-economic status.