Origins of black carbon from anthropogenic emissions and open biomass burning transported to Xishuangbanna, Southwest China


Lin Zhu , Xuyan Liu , Siwen Wang , Qianqian Zhang , Chunlai Jiang , Linlin Liang , Shihao Tang , Xingying Zhang , Xiuzhen Han

DOI:10.1016/j.jes.2021.12.020

Received May 17, 2021,Revised , Accepted December 24, 2021, Available online January 04, 2022

Volume 35,2023,Pages 277-289

Black carbon (BC) has importance regarding aerosol composition, radiative balance, and human exposure. This study adopted a backward-trajectory approach to quantify the origins of BC from anthropogenic emissions (BCAn) and open biomass burning (BCBB) transported to Xishuangbanna in 2017. Haze months, between haze and clean months, and clean months in Xishuangbanna were defined according to daily PM2.5 concentrations of >75, 35–75, and <35 µg/m3, respectively. Results showed that the transport efficiency density (TED) of BC transported to Xishuangbanna was controlled by the prevailing winds in different seasons. The yearly contributions to the effective emission intensity of BCAn and BCBB transported to Xishuangbanna were 52% and 48%, respectively. However, when haze occurred in Xishuangbanna, the average BCAn and BCBB contributions were 23% and 77%, respectively. This suggests that open biomass burning (BB) becomes the dominant source in haze months. Myanmar, India, and Laos were the dominant source regions of BC transported to Xishuangbanna during haze months, accounting for 59%, 18%, and 13% of the total, respectively. Furthermore, India was identified as the most important source regions of BCAn transported to Xishuangbanna in haze months, accounting for 14%. The two countries making the greatest contributions to BCBB transported to Xishuangbanna were Myanmar and Laos in haze months, accounting for 55% and 13%, respectively. BC emissions from Xishuangbanna had minimal effects on the results of the present study. It is suggested that open BB in Myanmar and Laos, and anthropogenic emissions in India were responsible for poor air quality in Xishuangbanna.

Copyright © Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.京ICP备05002858号-3