2020 Volume 55 Issue 2 Pages 34-49
The Community Multiscale Air Quality Model (CMAQ) was used to evaluate the impact of field biomass burning (BB) in Northeast China on the PM2.5 transboundary heavy pollution over Northeast Asia (Northeast China in China, and Hokkaido and Tohoku regions in Japan) in early spring of 2019. The Global Fire Assimilation System (GFAS) version 1.2 for the year 2019 was used for the field BB emissions in the base line simulation (Base). Northeast China was affected by both 10℃ higher temperatures than normal which could cause early snowmelt and lead to crop field burning. In fact, unusual hot spots in Northeast China were detected by satellite and helped GFAS to estimate the heavy BB pollutants. CMAQ in the Base case reasonably reproduced the daily mean PM2.5 mass concentrations in Northeast Asia during the evaluation period (from February to March) except for the end of February to the beginning of March when an intensive field BB occurred in Northeast China. Meanwhile, the other simulation with boosted BB sources from the cropland in Northeast China fairly captured the daily mean PM2.5 mass concentrations in Northeast Asia during this period. These results implied that the current GFAS emission in Northeast China was underestimated and that PM2.5 heavy pollution in the Hokkaido region, Japan, was attributed to the field BB from the cropland of Northeast China.
