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Characterizing grassland fire activity in the Flint Hills region and air quality using satellite and routine surface monitor data
Citation:
Baker, K., S. Koplitz, K. Foley, L. Avey, AND A. Hawkins. Characterizing grassland fire activity in the Flint Hills region and air quality using satellite and routine surface monitor data. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 659:1555-1566, (2019). https://doi.org/10.1016/j.scitotenv.2018.12.427
Impact/Purpose:
This work uses multiple sources of air quality and fire-related observations from the Flint Hills area in Kansas to analyze the impact of prescribed fires on over a dozen pollutants, including ozone, PM2.5 and species, mercury deposition, ammonia and carbon dioxide. Previous air quality modeling of this region has shown systematic over prediction of the impact of fire emissions on ozone and PM2.5. The observation-based analysis in this paper is used to characterize the timing (season, day of the week, hour of the day) of fires in this region, providing valuable information for improving modeling of prescribed fire emissions to be used in numerical air quality models. The paper also compares three different burned area products, FINN, GFED, NEI, that are used to support air quality modeling. The paper finds substantial differences between the products which could result in differences in how prescribed fire emissions are quantified. This finding is significant since these emissions are needed for the air quality modeling used by the state of Kansas to demonstrate how emissions from grassland burning in the Flint Hills region can contribute to ozone levels that exceed the National Ambient Air Quality Standard (NAAQS) in nearby urban areas including Wichita and Kansas City.
Description:
Prescribed grassland fires in the Flint Hills region of central Kansas and northern Oklahoma are common during March and April and emit pollutants that can have negative health impacts on humans. Local to regional scale impacts on air quality from grassland fires in this region are not well understood, which is important as these types of prescribed fires may increase in the future to preserve native grasses in the central U.S. Routine air quality and deposition measurements from sites in and near the Flint Hills were examined for coincident seasonal increases in prescribed grassland fires. Prescribed fire activity in this region was quantified using satellite detections and multiple publicly available products of area burned. March and April comprise over half (51 to 71%) of all annual fire detections in the Flint Hills region seen from satellites between 2007 and 2018 excluding drought years. Annual total fire detections in this region range between 20 to 50 thousand and account for approximately 10% of all fire detections in the contiguous United States. Annual acres burned in this region ranges from 0.2 to over 3 million acres, which is about 7% (range of 4 to 10%) of all wildland fire acres burned in the contiguous U.S. A comparison of weekly standardized anomalies suggests a relationship between periods of increased grassland fire activity and elevated levels of PM2.5 organic carbon, elemental carbon, potassium, and lead. Daily maximum aerosol optical depth, daily 1-hr maximum O3, NH3, SO2, oxidized nitrogen gases, and mercury concentration in rainwater also had increased levels when prescribed grassland fire activity was highest. This detailed characterization prescribed fire activity in the Flint Hills and air quality impacts will benefit future efforts to understand changes in atmospheric composition due to changing land management practices.
URLs/Downloads:
DOI: Characterizing grassland fire activity in the Flint Hills region and air quality using satellite and routine surface monitor data