Gases drawn into particles stay there

April 9, 2012
SPLAT II provides measurements of particles with unprecedented sensitivity and precision to scientists such as Alla Zelenyuk.

(Phys.org) -- Contrary to expectations, formation and growth of complex organic particles generated during oxidation of volatile organic molecules by ozone and nitrate follows a non-equilibrium path, according to a recent study in the Proceedings of the National Academy of Sciences.

The formation kinetic data show that the organic nitrates do not dissolve in the , but rather condense on quasi-solid particles' surfaces, where they are trapped, proving unequivocally that these particles are not in a liquid state. The study was conducted by University of California, Irvine chemist Prof. Barbara Finlayson-Pitts in collaboration with Dr. Alla Zelenyuk at Pacific Northwest National Laboratory.

These findings represent an important step in the development of a fundamental mechanistic understanding of the formation and properties of complex organic particles, putting into question prevailing assumptions used in current aerosol models. Reformulation of aerosol models would affect the predicted formation and evolution of , their role in heterogeneous chemistry, their projected impacts on air quality, visibility, and climate, and hence the development of reliable control strategies.

SPLAT, a one-of-a-kind single spectrometer that resides in EMSL, was used to characterize in great detail the properties of millions of particles that were formed in the 26-foot-long "aerosol flow tube" at AirUCI.

"What made these findings possible is the ability to characterize multitude of individual particles' properties with high precision," said Zelenyuk. "Incorporating what we found about these particles into models will provide fundamental understanding of formation and transformations of complex organic particles."

This research project represents the initial step towards developing a fundamental, mechanistic theory of organic particle formation and evolution. Future research will proceed to test how general the findings are to other organic particles formed under different conditions from different precursors. In parallel, a fundamental modeling framework that takes the experimental findings into account will be developed.

Explore further: When the air turns brown: Scientists discover reactions that create climate-changing brown carbon aerosol

More information: V Perraud, et al. 2012. "Nonequilibrium atmospheric secondary organic aerosol formation and growth." Proceedings of the National Academy of Science. 109:2836-2841. DOI: 10.1073/pnas.1119909109

Related Stories

Refining atmospheric climate models

February 1, 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 and Imre Consulting ...

Climate sensitivity greater than previously believed

December 20, 2011

Many of the particles in the atmosphere are produced by the natural world, and it is possible that plants have in recent decades reduced the effects of the greenhouse gases to which human activity has given rise. One consequence ...

Gases drawn into smog particles stay there, study reveals

February 21, 2012

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.

Recommended for you

New chemistry makes strong bonds weak

July 28, 2015

Researchers at Princeton have developed a new chemical reaction that breaks the strongest bond in a molecule instead of the weakest, completely reversing the norm for reactions in which bonds are evenly split to form reactive ...

Making polymers from a greenhouse gas

July 28, 2015

A future where power plants feed their carbon dioxide directly into an adjacent production facility instead of spewing it up a chimney and into the atmosphere is definitely possible, because CO2 isn't just an undesirable ...

New material opens possibilities for super-long-acting pills

July 28, 2015

Medical devices designed to reside in the stomach have a variety of applications, including prolonged drug delivery, electronic monitoring, and weight-loss intervention. However, these devices, often created with nondegradable ...

0 comments

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.