Inversed Emission Inventory for Chinese Air Quality (CAQIEI) version 1.0

The Inversed Emission Inventory for Chinese Air Quality (CAQIEI) version 1.0 is a new long-term top-down emission inventory in China developed by the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP, CAS), collaborated with China National Environmental Monitoring Centre (CNEMC) and other research institutes at home and abroad. It was produced by the chemical data assimilation system (ChemDAS) developed by the IAP, CAS which was constrained by observations from over 1000 surface air quality monitoring sites from CNEMC by using the ensemble Kalman filter (EnKF) and the Nested Air Quality Prediction Modeling system (NAQPMS).

It contains constrained monthly gridded emissions of NOx, SO2, CO, primary PM2.5, primary PM10, and NMVOCs in China from 2013 to 2020, with a horizontal resolution of 15 km. The evaluation results suggest that the CAQIEI can effectively reduce the biases in the a priori emission inventory, with the normalized mean biases ranging from −9.1% to 9.5% in the a posteriori simulation, which are significantly reduced from the biases in the a priori simulations (−45.6% to 93.8%).