Study suggests air quality regulations miss key pollutants

Sep 24, 2008

(PhysOrg.com) -- A new study led by the University of Colorado at Boulder reveals that air quality regulations may not effectively target a large source of fine, organic particle pollutants that contribute to hazy skies and poor air quality over the Los Angeles region.

According to the study, a much smaller percentage of organic haze than was previously thought is directly emitted by vehicles and industrial processes. Instead, 75 percent of fine, organic particle pollutants form when reactive gases called VOCs, or volatile organic compounds, are oxidized and condense onto existing particles in the air.

"Air quality regulations today effectively target most sources of 'primary,' or directly emitted particles," said lead author Ken Docherty, a researcher with the university's Cooperative Institute for Research in Environmental Sciences. "Yet our study indicates that the 'secondary,' or chemically formed particles contribute more significantly to poor air quality, even in very polluted urban regions.

"Our study suggests that regulations need to focus much more attention on the gases -- such as gasoline vapors -- that form secondary organic particles and create visible haze," he said. Other examples of VOCs include vapors from paints, varnishes, cleaning supplies, automotive products and dry-cleaned clothing.

The study will be published in the journal Environmental Science and Technology and was posted online Sept. 23.

According to California state regulatory agencies, motor vehicles and household products are both significant sources of VOCs in the Los Angeles region.

"Although current regulations do target many sources of VOCs, these regulations will need to further reduce VOC emissions and perhaps target still unknown sources to effectively reduce fine particle concentrations," said Docherty. He and his colleagues cautioned that it is not clear which VOCs are most responsible for haze formation.

Docherty also pointed out that while all types of fine particle pollutants are considered harmful, little is known about how a particle's chemical composition might exacerbate its impact on human health. Fine particles have diameters of less than 2.5 microns, or less than one-tenth the diameter of a human hair.

The CU-Boulder-led study employed several continuous and filter-based sampling techniques, as well as five different methods to estimate the amount of chemically formed, organic particles in haze. All five methods showed that 68 to 90 percent of total organic pollution hanging over the Los Angeles region during the afternoon is secondary in nature. During the morning commute, when direct emissions from vehicles are at their peak, secondary particles still make up about half of the organic haze.

"We have used almost all the methods that can be used to attack this problem, and the fact that they give consistent results at one location and time is very telling," said project director and CU-Boulder Professor Jose-Luis Jimenez. Jimenez conducted similar research in Pittsburgh in 2002 and Mexico City in 2006, where secondary organic particles also were found to contribute significantly to the region's poor air quality.

Provided by University of Colorado at Boulder

Explore further: UN moves toward major treaty for ocean biodiversity

add to favorites email to friend print save as pdf

Related Stories

The cost of Chinese air pollution

Jan 23, 2015

China's fabled air pollution assaulted Linda Greer, J76, the moment she arrived in Beijing in 2008, on her first trip there for the Natural Resources Defense Council (NRDC). "I literally could not see down the block," she ...

Beijing dangerous smog down four percent in 2014

Jan 05, 2015

Air pollution in Beijing dropped slightly last year, municipal authorities said, although levels of the most dangerous small particulate matter remained more than three times the internationally recommended ...

Pirate viruses caught in their own trap?

Dec 02, 2014

In order to infect a host cell and proliferate, some viruses, such as the hepatitis C virus, infiltrate the ribosomes, the molecular machines that assemble the proteins present in each of our cells. Viral ...

Mountains and winds confound particle distribution

Nov 05, 2014

Untangling complex relationships requires understanding and facts. Applying both, Pacific Northwest National Laboratory led research finding the true culprits instigating layers of tiny atmospheric particles ...

Recommended for you

Montana oil spill estimate lowered to 30,000 gallons

1 hour ago

Authorities have lowered their estimate of how much oil spilled from a broken pipeline beneath the Yellowstone River in eastern Montana, briefly contaminating the water supply of a city downstream.

British lawmakers demand freeze on fracking

15 hours ago

A committee of British lawmakers demanded a national moratorium on fracking due to environmental concerns on Monday, ahead of a crucial vote intended to boost the shale gas industry.

UN moves toward major treaty for ocean biodiversity

Jan 25, 2015

UN member states agreed Saturday to begin negotiations on a treaty to protect marine biodiversity in ocean areas extending beyond territorial waters, in a move heralded by environmental organizations.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

GrayMouser
not rated yet Oct 31, 2008
When did keys become a significant pollutant?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.