Gases drawn into smog particles stay there, study reveals

Feb 21, 2012
AirUCI researchers simulated smog compounds in the lab by mixing common household chemicals and outdoor air in this 26-foot-long “aerosol flow tube.” Credit: Veronique Perraud / AirUCI

Airborne gases get sucked into stubborn smog particles from which they cannot escape, according to findings by UC Irvine and other researchers published today in the Proceedings of the National Academy of Sciences.

The results could explain a problem identified in recent years: Computer models long used by the U.S. , California air regulators and others significantly underestimate organic aerosols – the major component of smog particles. Such pollution blocks views of mountains and has been linked to everything from asthma to heart attacks. It is also the largest unknown in climate change calculations.

"You can't have a lot of confidence in the predicted levels right now," said lead author Veronique Perraud, assistant project scientist to pioneering UCI air chemist Barbara Finlayson-Pitts. "It's extremely important, because if the models do a bad job of predicting particles, we may be underestimating the effects on the public."

An independent expert who reviewed the research for PNAS agreed.

"The conclusions are highly significant," said Purdue University atmospheric chemist Paul Shepson. "This paper should – and, I expect, will – have a big impact. We've known for nearly a decade that there's a huge difference between what's in the models and what's actually in the air. Thanks to this paper, we have a much better idea of why."

Scientists at UCI, a U.S. Department of Energy laboratory and Portland State University combined pinene, a common ingredient in household cleaners such as Pine Sol and outdoor emissions, with oxides of nitrogen and ozone to mimic smog buildup.

Models used by regulators for decades have assumed that in such pollution form liquid droplets that quickly dissolve potentially unhealthy . But the new work found that once gases are sucked into a particle, they get buried deeper and deeper.

"They check in, and they don't check out. They cannot escape. The material does not readily evaporate and may live longer and grow faster in total mass than previously thought," Finlayson-Pitts said. "This is consistent with related studies showing that may be an extremely viscous tar."

Perraud noted that broader study needs to be done: "The next logical step is to straighten the models out. We need enough follow-up data to do so."

Sophisticated tools made it easier to pinpoint the exact characteristics of chemical compounds in air. The scientists used a 26-foot-long "aerosol flow tube" at the AirUCI unit and a one-of-a-kind, 900-pound instrument known as SPLAT (a single particle laser ablation time-of-flight mass spectrometer) at the Pacific Northwest National Laboratory.

Explore further: Earthquake early alert system ready to expand in California

Related Stories

Chemists discover ozone-boosting reaction

Jul 20, 2009

(PhysOrg.com) -- Burning of fossil fuels pumps chemicals into the air that react on surfaces such as buildings and roads to create photochemical smog-forming chlorine atoms, UC Irvine scientists report in ...

Refining atmospheric climate models

Feb 01, 2011

(PhysOrg.com) -- A long, frustrating search for the source of "extra" aerosols seen in field experiments but not in models might have come to an end when scientists at Pacific Northwest National Laboratory ...

Sunlight changes aerosols in clouds

Oct 12, 2011

(PhysOrg.com) -- Today's climate models regard organic aerosols as static carbon-based molecules, but scientists at Pacific Northwest National Laboratory and the University of California, Irvine showed that ...

Recommended for you

"Ferrari of space' yields best map of ocean currents

4 hours ago

A satellite dubbed the "Ferrari of space" has yielded the most accurate model of ocean circulation yet, boosting understanding of the seas and a key impact of global warming, scientists said Tuesday.

Researcher studies deformation of tectonic plates

7 hours ago

Sean Bemis put his hands together side by side to demonstrate two plates of the earth's crust with a smooth boundary running between them. But that boundary is not always smooth and those plates do not always ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

tadchem
1 / 5 (2) Feb 21, 2012
So the particulate pollution acts to diminish the concentration of gaseous pollutants? As they grow in mass the pollutant particles would increase their settling speed, falling out of the air faster, and this negative feedback would enforce an upper limit on their size.
The particles collect toxic gases, fall out of the air, and leave the air cleaner.
Shootist
1 / 5 (2) Feb 21, 2012
So the particulate pollution acts to diminish the concentration of gaseous pollutants? As they grow in mass the pollutant particles would increase their settling speed, falling out of the air faster, and this negative feedback would enforce an upper limit on their size.
The particles collect toxic gases, fall out of the air, and leave the air cleaner.


Don't get excited. They never publish these things unless the news is bad.

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.