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DEVELOPMENT OF A BIOGENIC EMISSIONS INVENTORY FOR A SOUTHWESTERN, SEMI-ARID CITY

Jeremy E. Diem, Univ. of Arizona, Tucson, AZ; and A. C. Comrie

Determining the background or "natural" emission of pollutants is important for air pollution studies that attempt to quantify the impact of human activities on pollutant levels. In the case of ozone, its atmospheric concentrations are impacted partially by the emissions of ozone precursor chemicals (i.e. volatile organic compounds) from biogenic (i.e. vegetation) sources. This study describes the development of a summertime biogenic emissions inventory for the Tucson, AZ region. Relatively accurate non-methane hydrocarbon emission rates are available for many trees and shrubs of the eastern United States; however, rough and/or no emissions estimates are available for vegetation in the southwestern United States. In this study, we have developed a biogenic emissions inventory using land cover information derived from a satellite image. Results reveal the overwhelming importance of total leaf biomass with respect to the spatial variation in VOC emissions. Most biogenic VOC emissions in the Tucson region are emitted from pine and oak woodlands. These sources, located at high elevations, are at a considerable distance from the urbanized area. Overall, satellite imagery has proven to be a useful tool for developing a biogenic emissions inventory. The image's relatively fine spatial resolution (28.5 meters) allows for detailed investigations of specific VOC source areas.

The Second Symposium on Urban Environment