Analysis of Pollution Characteristics and Sources of PM2.5 During Heavy Pollution in Shijiazhuang City Around New Year's Day 2019

Abstract

We report on successive haze weather that occurred in Shijiazhuang City, China, from December 30, 2018 to January 15, 2019. There were 12 days of heavy atmospheric pollution during this period, which primarily involved aerosol fine particulate matter (PM2.5). This study analyzes the causes of the pollution using component analysis and by assessing pollution evolution, spatial and temporal distributions of PM2.5, pollution sources, and meteorological factors. The results showed that PM2.5 was mainly composed of secondary inorganic ions (65.4%) that were mainly sourced from coal combustion (24.4%) and industrial sources (23.7%). The contributions of sulfate and secondary inorganic sources increased significantly with increasing pollution. Pollution was affected by unfavorable meteorological conditions (e.g., a low air mass) and by the particular local terrain, static stability, high humidity, and near-ground reverse temperatures from the south-southeast and west-southwest directions. Contaminants from primary sources including coal combustion, industry, and motor vehicle exhausts accumulated quickly in front of the Taihang Mountains. Secondary transformation of gaseous pollutants and increasing moisture absorption of particulate matter increased PM2.5 concentrations. Sulfate explosion also increased pollution. We recommend that as part of emergency responses to heavy pollution events, emissions reduction measures should be implemented to strengthen the control of SO2, NOx, and NH3 emission sources of secondary inorganic precursors, especially SO2 emission sources (i.e., coal etc.). We further propose a strengthen of the management of atmospheric emission sources in Xinle, Wuji, Shenze, Jinzhou, and Xingtang counties in the northeast of the city to reduce the impact of local transmission.