Earth, wind, and fire: building meteorologically-sensitive biogenic and wildland fire emission estimates for air quality models

Emission estimates are vitally important for ensuring the accuracy of atmospheric chemical transport models. Many emission values are taken from static inventories of reported emissions. However, estimates of biogenic and wildland fire emissions, because of their sensitivity to meteorological conditions, need to be carefully constructed and closely linked with a meteorological processor in a chemical modeling system. In this paper, we will show three examples of emission modeling estimates in various stages of maturity. (1) The Biogenic Emissions Inventory System (BEIS) has been undergoing improvements since 1988. BEIS estimates biogenic hydrocarbons from vegetation and nitric oxide emissions from soils. This paper will highlight the changes in estimates of isoprene, perhaps the most prevalent volatile organic compound (VOC) emitted into the earth's troposphere. In the United States, it has been estimated that isoprene accounts for nearly 30% of all VOC emissions, and it has been shown that isoprene contributes significantly to the effectiveness of emission strategies for controlling surface concentrations of ozone. (2) Ammonia (NH3) is emitted primarily from agricultural operations, especially animal husbandry and fertilizer application. With the increased emphasis on aerosol modeling, it has been shown that emissions of NH3 affect the sensitivity of air quality predictions. Recent work has focused on improving knowledge of the temporal behavior of ammonia emissions from different kinds of sources. (3) Wildland fires is another source category that it is sensitive to meteorological and climatic conditions. Until recently, this emission category was resolved only at a state level and averaged only on a monthly basis. In this paper, we will report on efforts to model individual fires using input information from either field reports or satellite imagery. Finally, this paper will show how the three emission categories—biogenic, agricultural NH3, and wildland fires—are being incorporated into the National Weather Service's air quality modeling forecast system.

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