London, Feb 13 (IANS): The more time you spend at a signalled traffic intersection during your daily commute, the greater is your risk of developing respiratory and heart diseases, says a study led by an Indian-origin researcher.

Spending just two percent of journey time passing through traffic intersections managed by lights, contributes to about 25 percent of total exposure to harmful nanoparticles particles, the findings showed.

"It is not always possible to change your route to avoid these intersections, but drivers should be aware of the increased risks at busy lights," said lead author Prashant Kumar from the University of Surrey in Britain.

"The best ways to limit your exposure is to keep vehicle windows shut, fans off and try to increase the distance between you and the car in front where possible," Kumar, an alumnus of Indian Institute of Technology Delhi, suggested.

The team monitored drivers' exposure to air pollutants at various points of a journey.

Signalised traffic intersections were found to be high pollution hot-spots due to the frequent changes in driving conditions.

With drivers decelerating and stopping at lights, then revving up to move quickly when lights go green, peak particle concentration was found to be 29 times higher than that during free flowing traffic conditions.

As well as concentration, researchers found that as cars tend to be close together at lights, the likelihood of exposure to vehicle emissions is also significantly increased.

The study appeared in the journal Atmospheric Environment.