Researchers say that airplane traffic might be the reason behind the growing air pollution.
In a bid to find out what causes pollution in Los Angeles, researchers examined the Los Angeles International Airport (LAX), world's sixth busiest airport. For 29 days they drove around the area within 10 miles downwind of the airport to measure levels of air pollutants.
Their analysis shows that over a 23-square-mile area, particle number concentrations were double that of background levels and at a stretch of 9 square miles, levels were five times higher than background. Moreover, the particle number levels shot up by 10 times than the background levels within just 2 miles of the airport.
The researchers also examined pollution from vehicle exhausts. But, the results showed that automobiles contributed less than 5 percent of the particle number concentration levels. This shows that airplane traffic was the main culprit for polluting air in Los Angeles.
Researchers Scott Fruin, D.Env. P.E., Neelakshi Hudda and colleagues said that the effects of this pollution can continue up to 10 miles away from the airport.
The study results suggested that airports can be a significant source of pollution.
Last month, a research by the American Lung Association stated that Los Angeles tops the cities in the U.S. with worst air quality. And the city also violates the federal health standards for ozone an average of 122 days a year.
"Air pollution is not just a nuisance or the haze we see on the horizon; it's literally putting our health in danger," Bonnie Holmes-Gen, senior policy director of the American Lung Assosiation in California said then, according to The Los Angeles Times. "We've come a long way, but the status quo is not acceptable," he added.
Ultrafine particles have been an issue of concern for public health. They form from condensation of hot exhaust vapors and can deposit deeply into the lungs that might also enter the bloodstream. This can lead to development of atherosclerosis (blocked arteries) and can make other health conditions, such as asthma, worse.
The current findings are published in the journal 'Environmental Science & Technology.'
