Skip to Main Content

Latest News

Advertisement
Advertise Here
September 28, 2010
DOI:10.1021/CEN091610155341

Counting Carbon

Climate Change: Swedish researchers develop novel isotopic fingerprinting method for water-soluble organic carbon

Jeffrey M. Perkel

CARBON COUNTRY Boreal forests are major contributors of volatile organic carbon, the precursors of water-soluble organic carbon. Shutterstock
CARBON COUNTRY Boreal forests are major contributors of volatile organic carbon, the precursors of water-soluble organic carbon.
  • Print this article
  • Email the editor

Latest News



October 28, 2011

Speedy Homemade-Explosive Detector

Forensic Chemistry: A new method could increase the number of explosives detected by airport screeners.

Solar Panel Makers Cry Foul

Trade: U.S. companies complain of market dumping by China.

Novartis To Cut 2,000 Jobs

Layoffs follow similar moves by Amgen, AstraZeneca.

Nations Break Impasse On Waste

Environment: Ban to halt export of hazardous waste to developing world.

New Leader For Lawrence Livermore

Penrose (Parney) Albright will direct DOE national lab.

Hair Reveals Source Of People's Exposure To Mercury

Toxic Exposure: Mercury isotopes in human hair illuminate dietary and industrial sources.

Why The Long Fat?

Cancer Biochemistry: Mass spectrometry follows the metabolism of very long fatty acids in cancer cells.

Text Size A A

To model climate change and plan new environmental policies, researchers must understand the myriad chemicals floating around in the atmosphere. And the atmosphere is swimming in carbon, such as greenhouse gases, volatile organic carbon (VOC) molecules, and secondary organic aerosols (SOA).

But to determine how we can regulate all these organic molecules, scientists must first determine where they come from. Now researchers describe a new isotopic fingerprinting technique that can help sort out atmospheric carbon's origins (Anal. Chem., DOI: 10.1021/ac1014436).

Water-soluble organic carbon (WSOC), one particular fraction of atmospheric carbon, forms when VOCs oxidize in the atmosphere into less-volatile derivatives. WSOC can both reflect sunlight back into space and seed clouds, says biogeochemist Õrjan Gustafsson of Stockholm University in Sweden, so they tend to have a cooling effect on climate.

WSOC can derive from man-made or natural sources, which researchers can distinguish isotopically. Plants synthesize VOCs, such as the chemicals responsible for that distinctive pine forest smell, from atmospheric CO2, which contains some carbon-14. Meanwhile, fossil fuels' carbon-14 content has long since decayed and is essentially zero. So WSOC derived from living plants, including burned wood or biomass, has a different carbon-14/carbon-12 ratio than carbon released from fossil fuels.

In the past, researchers have detected these isotopic differences essentially by pumping air through filters and fingerprinting the trapped particulate material via accelerator mass spectrometry. Gustafsson and his colleagues modified these methods to specifically assess the WSOC fraction by adding a water-extraction step. The new method also measures the carbon-13/carbon-12 isotope ratio to gather information on the particular kind of plant matter, such as trees or grasses, that yielded the WSOC.

"This is in some sense 'environmental forensics,'" Gustafsson says.

The team tested the new method in a survey of Stockholm air in late summer 2009. They found that about 88% of the sampled carbon came from Sweden's boreal forests. Their data agrees with two other studies of WSOC that pinpoint biogenic emissions as important VOC sources in the U.S.

Gustafsson says that identifying what processes produce aerosols, such as burning fossil fuels or wood, can help regulators make more informed decisions regarding anthropogenic sources of atmospheric carbon.

But regulators should not forget about the biogenic fraction, says atmospheric aerosols expert Rodney Weber of Georgia Tech. He and other researchers have shown that biogenic WSOCs can be controlled partially by cutting other man-made pollutants, such as nitrogen oxides, because these anthropogenic chemicals help convert biogenic VOCs into organic aerosols.

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2011 American Chemical Society
  • Print this article
  • Email the editor

Services & Tools

ACS Resources

ACS is the leading employment source for recruiting scientific professionals. ACS Careers and C&EN Classifieds provide employers direct access to scientific talent both in print and online. Jobseekers | Employers

» Join ACS

Join more than 161,000 professionals in the chemical sciences world-wide, as a member of the American Chemical Society.
» Join Now!