Transboundary air pollution in relation to open burning in Upper Southeast Asia

Abstract

© 2019, Thai Society of Higher Eduation Institutes on Environment. All rights reserved. This study aims to analyse fire hotspots using two NASA’s sensor systems; Moderate Resolution Imaging Spectroradiometer (MODIS), and Visible Infrared Imaging Radiometer Suite (VIIRS) and assess their impacts on air quality. Geographic information system (GIS) was used to create maps of fire hotspots and their density. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to analyze 24- and 72-hour backward trajectory (BWT) of air mass movement to Chiang Mai city during February-April 2018. Two levels of air mass arriving were set at 10 m and 1,500 m above ground level (AGL). During the study period, directions of air mass movement were mostly from western and south-western of the city. Burned areas obtained from both MODIS and VIIRS systems were significantly different (p < 0.05). Correlations between PM2.5 concentrations and Burned areas for both 24-and 72-hour BWT obtained from VIIRS were better than those of MODIS at both levels (10 and 1,500 m AGL). Influence of local open burning on air pollution was observed from both systems but VIIRS provided slightly higher correlation with hotspot number than MODIS. Both systems provided similar results for transboundary air pollution (1,500 m AGL).