Bottom-up emission inventories of multiple air pollutants from open straw burning: A case study of Jiangsu province, Eastern China

Abstract

Open straw burnings during harvest season generated large amounts of air pollutants in a short duration, resulting in significant visibility reduction, air quality deterioration and adverse impact on human health. In this study, a bottom-up approach of county level emission inventory from open straw burning was developed. A 1 km resolution inventories for Jiangsu province, Eastern China, was established as a case study. In order to increase temporal-spatial resolution, county level, seasonal data and local parameters were preferentially used. Per capita disposable income of rural residents was used to adjust burning proportion for different cities. Emissions during summer-harvest and autumn-harvest seasons were calculated separately. The inventory was further allocated based on both MODIS fire product and land use data of cropland. Total emissions of SO2, NOx, THC, NH3, OC, BC and primary PM2.5 from open straw burning in 2015 were 3.72, 15.25, 43.52, 2.65, 16.08, 2.08 and 44.70 Gg, respectively. From 2010 to 2015, provincial emissions decreased by 50.7% in average, and the difference between southern and northern Jiangsu has been even enlarged. Autumn-harvest crop straw contributed 63%–67% to NH3, OC and PM2.5, while summer-harvest crop straw contributed 60% to BC. Wheat and rice straws burning accounted for the majority of emissions at 80%–91% of the total for all 7 pollutants. Uncertainties ranged from a low of within 29% for BC to a high of within 40% for NH3. The EFs and the crop production of autumn-harvest rice and summer harvest wheat, are the key uncertainty sources.