A comprehensive inventory of agricultural atmospheric particulate matters (PM10 and PM2.5) and gaseous pollutants (VOCs, SO2, NH3, CO, NOx and HC) emissions in China

Atmospheric pollutants emitted from agriculture are a key factor in regional air quality. However, previous studies of agricultural sources have only focused on agricultural burning, livestock or fertilizer; comprehensive agricultural emission inventories involving main agricultural operations are still lacking in China, which would limit our ability to understand, predict and control the effects of agricultural emissions on air quality and human health. This study presents the latest county-level sector-specific emission inventories of particulate matter (PM10 and PM2.5) and gaseous pollutants (VOCs, SO2, NH3, CO and NOx) from six agricultural sectors, including land preparation, crop harvesting, crop residue burning, grain processing, fertilizer application and agricultural machinery, based on a bottom-up emission estimation method. Agricultural activity data were collected from statistical yearbooks, and emission factors of each operation were adopted from published data. Annual emissions of PM10, PM2.5, VOCs, SO2, NH3, CO, and NOx from agricultural operations during 2015 in China were estimated to be 2867.4 Gg, 1941.1 Gg, 2321.9 Gg, 139.6 Gg, 1072.7 Gg, 10149.9 Gg and 1433.2 Gg, respectively. Higher pollutant emissions are found in Eastern and Central China. Atmospheric pollutant emissions show a primary peak in October in North, Northeast, Northwest and Southwest and in June and July in other regions. The historic trends (1997-2015) of agricultural emissions have shown annual average growth rates of 0.9%/yr, 1.3%/yr, 1.5%/yr, 2.5%/yr, 1.1%/yr, 1.2%/yr and 0.6%/yr for PM10, PM2.5, VOCs, NOx, SO2, CO and NH3, respectively. The detailed agricultural emission inventory generated by this study could provide useful information for air quality modeling and support the development of appropriate pollution control strategies.