Bottom-up re-estimations of greenhouse gas and atmospheric pollutants derived from straw burning of three cereal crops production in China based on a national questionnaire

Crop straw open burning is considered as an important source of greenhouse gas and atmospheric pollutants emissions, which affects global climate change and regional air quality. However, due to the limitation of data availability, the current emission estimation of greenhouse gas and atmospheric pollutants from crop straw open burning remains uncertain based on the bottom-up method. Therefore, we re-estimate the greenhouse gas and atmospheric pollutants from crop straw open burning at the county level based on a national questionnaire and the up-to-data emission factors. Results showed that emissions of CO2, CH4, N2O, PM10, PM2.5, NMVOC, NH3, NOx, SO2, CO, BC, and OC from open straw burning are 69250.8 Gg, 242.9 Gg, 4.2 Gg, 771.0 Gg, 539.7 Gg, 498.2 Gg, 34.7 Gg, 200.4 Gg, 24.8 Gg, 3426.5 Gg, 63.0 Gg, and 278.5 Gg, respectively, which were lower than those of previous studies. Maize was the largest contribution, followed by wheat, rice. Hotspots for greenhouse gas and atmospheric pollutants from straw burning are mainly distributed in the 54 counties of northeast China, accounting for 20% of total emissions on average. However, the high emission of maize, wheat, and rice are mainly located at the counties of north China, northeast China, and middle-lower Yangtze River region, respectively. This study not only provides the targeted counties that need decrease further the straw open burning, but also improves the precision of emission estimation that benefits air quality modeling.

Automated summary

The study re-estimated the greenhouse gas and atmospheric pollutants emissions from crop straw open burning at the county level in China, finding that the majority of emission hotspots are located in the 54 counties of northeast China, accounting for 20% of total emissions on average. Maize, wheat, and rice were identified as the primary sources of emissions, mainly located in north China, northeast China, and middle-lower Yangtze River region, respectively.