Impact of Beijing's “Coal to Electricity” program on ambient PM2.5 and the associated reactive oxygen species (ROS)

• Published in: Journal of environmental sciences (China) 2023-11, Vol.133, p.93-106
• Main Authors: Zhao, Kaining, Zhang, Yuanxun, Shang, Jing, Schauer, James J., Huang, Wei, Tian, Jingyu, Yang, Shujian, Fang, Dongqing, Zhang, Dong
• Format: Article
• Language: English
• Subjects: Correlation; Factor analysis (FA); PM2.5; Principal component regression (PCR); Reactive oxygen species (ROS)
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2022.06.038

The Beijing “Coal to Electricity” program provides a unique opportunity to explore air quality impacts by replacing residential coal burning with electrical appliances. In this study, the atmospheric ROS (Gas-phase ROS and Particle-phase ROS, abbreviated to G-ROS and P-ROS) were measured by an online instrument in parallel with concurrent PM2.5 sample collections analyzed for chemical composition and cellular ROS in a baseline year (Coal Use Year-CUY) and the first year following implementation of the “Coal to Electricity” program (Coal Ban Year-CBY). The results showed PM2.5 concentrations had no significant difference between the two sampling periods, but the activities of G-ROS, P-ROS, and cellular ROS in CBY were 8.72 nmol H2O2/m3, 9.82 nmol H2O2/m3, and 2045.75 µg UD /mg PM higher than in CUY. Six sources were identified by factor-analysis from the chemical components of PM2.5. Secondary sources (SECs) were the dominant source of PM2.5 in the two periods, with 15.90% higher contribution in CBY than in CUY. Industrial Emission & Coal Combustion sources (Ind. & CCs), mainly from regional transport, also increased significantly in CBY. The contributions of Aged Sea Salt & Residential Burning sources to PM2.5 decreased 5.31% from CUY to CBY. The correlation results illustrated that Ind. & CCs had significant positive correlations with atmospheric ROS, and SECs significantly associated with cellular ROS, especially nitrates (r = 0.626, p = 0.000). Therefore, the implementation of the “Coal to Electricity” program reduced PM2.5 contributions from coal and biomass combustion, but had little effect on the improvement of atmospheric and cellular ROS.