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Contributions of prescribed fire to air quality and health

Principal Investigator: 

Georgia Institute of Technology

The objectives of this study are to: 1) Estimate the contributions of prescribed burning to both fine particulate matter (PM2.5) and ozone (O3) levels in the Southeastern US; 2) Quantify the effects of prescribed fire smoke on rates of emergency department (ED) visits; and 3) Assess how the observed health impacts vary across strata defined by age, sex, and socioeconomic markers.

Funded under

Poster abstract for HEI Annual Conference 2023

Impact of Prescribed Fire on Air Quality in Southeastern US during 2015–2020

Kamal J. Maji1, Zongrun Li1, Jennifer D. Stowell2, Chad Milando2, Yongtao Hu1, Gregory A. Wellenius2, Patrick L. Kinney2, Armistead G. Russell1, Ambarish Vaidyanathan1,3, and M. Talat Odman1

1Georgia Institute of Technology, Atlanta, Georgia, USA; 2Boston University, Boston, Massachusetts, USA; 3Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Background. Prescribed fires are planned and intentionally set wildland fires, which are commonly used for reducing the risk of wildfires and managing the wildland ecosystems. Prescribed fires are conducted under weather conditions different from those conducive to wildfires, resulting in a different type of smoke with different constituents, concentrations, and proportions. To protect public health, there is a need for a better understanding of the impact of prescribed fires on air quality, especially in southeastern US where many people live at the wildland-urban interface.

Methods. This study aimed to estimate the daily impact of prescribed fires on air quality using satellite fire products, ground-based observations and air quality modeling. (1) We estimated daily prescribed fire information by discerning agricultural fire and wildfire from satellite-derived Fire INventory from NCAR (FINN), based on their location and duration. (2) We used a linear regression model to adjust burned area from FINN with burn permit records based on grid-level matching. The adjusted burned area was applied to BlueSky Smoke Modeling Framework to estimate three-dimensional prescribed burning emissions for southeastern US. (3) We simulated the prescribed fire impacts on daily average PM2.5, and daily maximum 8hr average O3 (MDA8-O3) during the 2015–2020, using the Community Multiscale Air Quality (CMAQ) model at 4-km horizontal grid resolution. The simulated PM2.5 and MDA8-O3 fields were then fused with daily observations at ambient surface monitors. Finally, the observation-fused daily average PM2.5 and MDA8-O3 fields were scaled by the fraction of the burn impact obtained from CMAQ for each day and each grid cell to generate “observation-adjusted burn impacts” on PM2.5 and MDA8-O3.

Results. The impacts of prescribed fire on spatiotemporal variations of total-PM2.5 and MDA8-O3 are significant across the study region. In 2015, prescribed fire contribution to daily average PM2.5 across the region was 1.3±0.5 µg/m3 (range: 0.3-4.0), whereas during active fire season (January-April) the contribution was 1.6±0.7 µg/m3 (0.4-5.2). The highest impact was observed in March, 1.8±0.9 µg/m3 (0.4-7.1). Similarly, in 2020, prescribed fire contributions to PM2.5 were 1.1±0.5 (0.2-2.8), 1.1±0.5 (0.3-4.5) and 1.6±0.9 (0.3-8.1) µg/m3 during the year, fire-season and March, respectively. Contribution to MDA8-O3 was relatively low, 0.35± 0.1 (0.1-0.9) ppb in 2015 and 0.2± 0.1 (0.05-0.7) ppb in 2020. Although, prescribed fire was responsible for increases of >1 ppb in MDA8-O3 during March in large parts of the region, average contribution was 0.6± 0.3 (0.1-2.6) ppb in 2015 and 0.4± 0.3 0.4± 0.3 (0.05-4.2) ppb in 2020.`

Conclusions. Prescribed fires contribute significantly to daily PM2.5 and O3 concentrations in southeastern US. Exposure to air pollution from prescribed burns may be associated with a higher risk of ED visits for respiratory and cardiovascular disease.