Investigators and Program Directors
Vincent A. Dutkiewicz
Research Scientist, Wadsworth Center, Environmental Atmospheric Chemistry
Asssociate Professor, School of Public Health, Environmental Health Sciences
Ph.D., University at Albany (1977)
Postdoctral Training: NYS Health Department
Email: dutkiew@wadsworth.org
Research Interests
My research has covered a wide range of topics with a single approach; identify key species that can be used as tracers to simplify otherwise complex processes in the atmosphere and elucidate important fundamentals. This has included studies of ozone in the stratosphere, troposphere and surface air, long-distance transport of fossil fuel emissions, and gas- and aqueous-phase oxidation of sulfur dioxide gas to sulfate in the atmosphere. The later is the focus of present research.
Once released by fossil fuel combustion, sulfur dioxide reacts slowly in sunlight with hydroxyl radicals, about 0.5 percent per hour, to produce aerosol sulfate. Wet and dry deposition of sulfate are the primary way sulfur dioxide is removed, so a slow rate of reaction means it can travel long distances. Cloud droplets need seed aerosols or cloud condensation nuclei (CCN) to form. Sulfate is the most abundant aerosol in the Northeast and when concentrations are elevated, acidic clouds and precipitation result. However, sulfur dioxide dissolved in cloud droplets with pH under 5.0 rapidly react with any hydrogen peroxide present. The in-cloud oxidation of sulfur dioxide by this mechanism is expected to exceed 300% per hour. The resulting sulfuric acid in the cloud is chemically indistinguishable from that formed from nucleation scavenging of aerosol sulfate so it had not been possible to accurately evaluate the role of clouds in acidic deposition. However, a technique developed at this laboratory now allows direct determination of the conversion of sulfur dioxide into sulfuric acid in clouds. The method uses the element Se that is released into the air along with S during coal combustion. As emissions cool, Se quickly forms sub-micron aerosols that are transported downwind along with the S species but that are not affected by chemical reactions. When a cloud forms, sulfate and Se aerosols are used as CCN and are taken up to form droplets at the same rate. If no sulfur dioxide is oxidized in the cloud, the ratio of sulfate/Se in the droplets will be the same as in the pre-cloud air. However, if oxidation occurs, sulfur dioxide and hydrogen peroxide will be consumed and the ratio of sulfate/Se in cloud droplets will increase. The ratio in the cloud drops relative that in pre-cloud air can be used to quantify how much sulfur dioxide was oxidized.
Extensive field campaigns are being conducted at Whiteface Mountain, at the Atmospheric Sciences Research Center, SUNY under USEPA funding. This program will help to improve our understanding of in-cloud chemical reactions and help to establish an accurate quantitative relationship between sulfur emissions and downwind acid deposition.
Contact Information
Phone: (518) 474-7999
Fax: (518) 473-2895
Email: dutkiew@wadsworth.org