Estimation of Ultrafine Particulate Matter Emissions from Biomass Burning Using Satellite Imaging and Burn Severity

Abstract

Fine and ultrafine particles emitted from open biomass burning seriously affect air quality in many countries in Southeast Asia during haze episodes. In this study, PM0.1 and PM2.5 emissions were estimated for Thailand using agricultural residue burning. Data from Landsat-8 and Sentinel-2 satellites was obtained from 2016 to 2019. Burn severity was evaluated using NIR and SWIR bands. Results suggested agricultural residue burning as a significant contributor accounting for 82-90% of the total burned area, and the forest fires contributed the remainder. Further, the burned areas from agricultural waste during El Niño years were up to 2 times as high as those during La Niña years. Rice residue burning was the most significant contributor, followed by sugarcane and maize. Major burned areas of rice and sugarcane residue were in the northeast. Annual average PM2.5 and PM0.1 emissions from crop residue burning in Thailand were about 43.3 and 4.1 Gg/year, respectively. PM0.1 emissions during El Niño years were also larger at 4.2-5.2 Gg/year compared to 3.7-3.4 Gg/year during La Niña. PM0.1 emissions from crop residue burning were about 10% of PM2.5. These emissions affect local air quality in Thailand and neighboring countries due to long-range transport and vice versa. Annual mean PM0.1 concentrations during the open biomass burning period ranged from 6.6 to 18.9 µg/m3. PM0.1-bound PAH concentrations were found to be 3-8 times higher than the background. The study highlights the estimation of fine and ultrafine particle emissions from open biomass burning useful for other researchers.