Airplane traffic in air enters health danger zone

Stuck on the road for ages amid the crawling traffic this morning, thinking about the growing air pollution? Look up in the sky - no, not to pray to the almighty again.

Heavy airplane traffic can contribute even more pollution and the effect continues for up to 16 km away from the airport - leaving residents near airports around the world in a health danger zone, a significant study indicates.

In the study, researchers suspected that residents near Los Angeles International Airport (LAX) - the sixth busiest airport in the world - were getting exposed to excessive doses of pollution from airplanes even farther from the runways.

During its busiest times, 40 to 60 jets take off and land every hour from LAX.

Over a period of 29 days, the scientists drove the area within 16 km downwind of the airport to measure levels of air pollutants.

The area included densely packed residential neighbourhoods flanked by three major freeways.

They found that over a 23-square-mile area, particle number (PN) concentrations were double the background levels (that is, the PN concentrations without the LAX contribution).

Over nine square miles, levels were five times higher than background.

And within nearly two miles east of the airport, PN levels were nearly 10 times higher.

Based on their calculations, scientists concluded that within the area they found to have elevated pollution from the airport, automobiles contributed less than five percent of the PN levels.

"The LAX should be considered one of the most important sources of PN in Los Angeles," the scientists stated in the report published in the ACS journal Environmental Science & Technology.