Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study: Acidic surfaces on atmospheric aerosols greatly increase secondary aerosol formation

25.10.2002


Atmospheric particles that become acidic through exposure to such pollutants as sulfuric acid can lead to vast increases in the formation of secondary organic aerosols, a new study indicates. Such aerosols are major components of the unsightly haze that hangs over cities and oil refineries and even affects otherwise pristine U.S. national parks.



A report on the research appears in Friday’s (Oct. 25) issue of the journal Science. Authors, all at the University of North Carolina at Chapel Hill, are Dr. Myoseon Jang, research associate; doctoral students Nadine M. Czoschke and Sangdon Lee; and Richard M. Kamens, professor of environmental sciences and engineering at the UNC School of Public Health.

"We think this exciting work is potentially very important and so do other scientists we have discussed it with across the United States," said Kamens. "What Dr. Jang has done in our laboratory was to discover an acid-catalyzed process that brings about secondary organic aerosol formation. "She also has found that this under-appreciated reaction may generate five to 10 times more aerosol in the atmosphere than we previously thought," he said. "It appears to explain a number of different kinds of phenomena that lead to aerosol formation."


Jang’s "ground-breaking" new research involves testing aerosols in reaction chambers and large outdoor smog chambers and determining what happens to them under varying experimental conditions, Kamens said.

In the new work, scientists introduced fine inert particles known as seed aerosols into Teflon film reaction chambers, he said. Into some chambers they injected identical particles coated with 2 percent to 5 percent sulfuric acid, which is about the same level found on tiny bits of floating diesel soot.

"What they did then was to introduce into the gas phase atmosphere of the chambers aldehydes and alcohols," Kamens said. "Dr. Jang found that when the aldehydes and alcohols were present, there was a huge increase in the amount of aerosol that formed."

Studies with a variety of different aldehydes, which are formed in the atmosphere by oxidation of emitted hydrocarbons, revealed that some aldehydes derived from aromatic compounds were far more reactive in producing aerosols than scientists believed. Aromatic compounds come largely from automobile and other exhausts, while trees generate massive amounts of terpenoid hydrocarbons, which also form aldehydes and particles in the atmosphere subject to similar acid-catalyzed aerosol-producing reactions.

Jang’s discovery appears to fill an important hole in scientists’ understanding of atmospheric chemistry, Kamens said. Her data also mirrors natural data collected by a Rutgers University team in the Appalachians’ Smoky Mountains under the direction of Dr. Barbara Turpin.

"People from NOAA -- the National Oceanic and Atmospheric Administration -- got very excited about this work at a recent aerosol research meeting in Charlotte," he said. "That was because it seems to explain atmospheric reactions going on over Houston, where refineries produce very large emissions of volatile organic compounds and also sulfur dioxide.

"Using Dr. Jang’s theory and findings, they immediately thought that what has been happening there was that sulfur dioxide was being oxidized as sulfuric acid. Then the sulfuric acid was acid-catalyzing organic reactions in the plume over the petroleum refineries to form huge, huge bursts of particles that nobody really understood before."

The UNC experiments should lead to new insights into global warming, photochemical reactions and weather and, possibly, some useful manipulation of them, Kamens said. They also could have important implications for pollution control and health.

"Environmental Protection Agency researchers also have said they are very interested in this work, and we’re going to share our information with them soon," he said.

Mathematical models the team is creating will help them predict what would happen in the atmosphere in response to lowering volatile organic emissions and other pollutants from cars, refineries and other sources, the scientist said.


The National Science Foundation’s Atmospheric Chemistry Division and the EPA’s STAR (Science to Achieve Results) program supported the exploratory studies with grants to Kamens’ research group.

Note: Kamens and Lee can be reached at (919) 966-5452 and 966-3861, respectively, or kamens@unc.edu and mjang@email.unc.edu

By DAVID WILLIAMSON
UNC News Services

David Williamson | EurekAlert!

More articles from Earth Sciences:

nachricht Multi-year submarine-canyon study challenges textbook theories about turbidity currents
12.12.2017 | Monterey Bay Aquarium Research Institute

nachricht How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>