Integrated emission inventory and modelling to assess the distribution of particulate matters from rice straw open burning in Hanoi, Vietnam

Abstract

Rice straw open burning (RSOB) is a major environmental issue in many Asian countries, including Vietnam, during every crop season. This study integrates activity data (post-harvest rice straw) from the SAR Sentinel-1A satellite with an empirical survey to estimate air pollutants (PM10 and PM2.5) emissions from RSOB in Hanoi for the year 2020. According to the findings, Hanoi city has 125.5 thousand ha of rice cultivation area in 2020, producing 725 thousand tons of rice and leaving behind approximately 556 thousand tons of rice straw and stubble on the field. Farmers burning the rice straw open-field is a long-standing practice that emits 517.8 tons of PM10 and 472.3 tons of PM2.5 each year. The results of the ADMS dispersion model show that the maximum hourly averaged concentrations of PM10 and PM2.5 appear at 8 p.m. at values of 90.5 μg/m3 and 82.6 μg/m3 for the winter-spring crop and 16.8 μg/m3 and 15.3 μg/m3 for the summer-autumn crop, respectively. The hotspot locates most clearly at the South-Eastern part of the city, corresponding to the region with the largest crop cultivating area. Emission from RSOB has contributed to the local air pollution of Hanoi and its surrounding areas, including non-cultivation and no burning areas.