Spatial and temporal variation characteristics of atmospheric NO2 and SO2 in the Beijing-Tianjin-Hebei region before and after the COVID-19 outbreak

Abstract

Emergency response mechanisms were activated throughout China during the COVID-19 outbreak. It is different from the temporary, partial, and limited pollution control measures taken to ensure the regional environmental quality during several important events such as the 2008 Beijing Olympic Games and the 2014 Asia-Pacific Economic Cooperation (APEC). During the COVID-19 epidemic period, extensive movement of people and almost all unnecessary industrial production (necessary industrial production refers to the production of food, epidemic prevention materials, etc.) have been severely restricted, so transportation and industrial production have been greatly reduced. This is a rare extreme emission reduction scenario that presents a unique opportunity for atmospheric research. In this study, based on hourly mass concentration data of NO 2 and SO 2 from atmospheric monitoring sites in the Beijing-Tianjin-Hebei (BTH) region during the COVID-19 epidemic period, the changes in transportation and industrial production in the region, data statistics, and spatial analysis were used to analyze the pollution changes and their causes. The results indicate that the NO 2 and SO 2 concentrations in the BTH region decreased significantly during the epidemic period. The spatial distribution pattern of NO 2 pollution in the BTH region was "high in the southeast and low in the northwest," and SO 2 pollution in the BTH region was high in the southern and eastern parts of Hebei. The initiation of emergency response level 1 had an obvious effect on reducing NO 2 and SO 2 pollution in the region, while the impact of emergency response level 2 and below was limited. Compared with the single traffic control, the comprehensive control, similar to the emergency response, had a better effect on reducing NO 2 pollution in the region. The control of major large cities in the region also had a certain effect on alleviating NO 2 and SO 2 pollution in the entire region. Moreover, for activities under short-term control, it is particularly important to guard against the "retaliatory growth" after the control is lifted. By reducing and controlling some polluting industries in industrial production, the degree of NO 2 and SO 2 pollution in the region can be effectively reduced. The manufacturing industry of chemical raw materials and the chemical products and non-metallic mineral products industry made a great contribution to the change in industrial source pollution emissions in the BTH region during the COVID-19 epidemic. Road traffic emissions remained an important source of NO 2 emissions in the BTH region during this period. NO 2 emission reduction can be effectively achieved by controlling road traffic and transportation.

Concentration and source changes of HONO during the COVID-19 lockdown in Beijing

“…1i). This is similar to that reported by Cui et al (Cui et al, 2020) and Shen et al (Shen et al, 2021). The mean concentrations of NOx decreased significantly (P < 0.05) from 45.35 ± 38.86 ppb in P1 to 19.44 ± 14.42 ppb in P2, dropping by about 57%.…”

Atmospheric Deposition of Particulate Matter and Micropollutants as a Major Mass Transport Route to Surface Water in Winter: Measurement and Modeling in Beijing in 2014 and 2021

“…During the COVID-19 pandemic period, Beijing strengthened the patrol at the city border of Beijing and encouraged flexible work modes such as telecommuting and working from home to reduce traffic, large-scale personnel relocation was prohibited, and almost all nonessential industrial production was shutdown. − Due to the relocation of coal-fired power plants and other pollution-heavy industries out of Beijing, , the air quality in 2021 was significantly better than that in 2014 (Figure b) in Beijing. The maximum PM 2.5 concentration in January–February 2014 was 466 μg m –3 (January 16, 2014), while that in January–February 2021 was 254 μg m –3 (February 13, 2021).…”

High-Resolution Daily Spatiotemporal Distribution and Evaluation of Ground-Level Nitrogen Dioxide Concentration in the Beijing–Tianjin–Hebei Region Based on TROPOMI Data

“…The Beijing-Tianjin-Hebei region is one of the most polluted areas in China, and monitoring the emission of nitrogen dioxide has always been a focus of air pollution prevention and control work. Our study aims to provide a high-resolution spatiotemporal distribution of surface nitrogen dioxide concentration in this region, which can be used to report and evaluate pollution control policies and measures [7,8].…”