Changes in China's anthropogenic emissions during the COVID-19 pandemic

Abstract

Abstract. The COVID-19 pandemic lockdowns led to a sharp drop in socio-economic activities in China in 2020, including reductions in fossil fuel use, industry productions, and traffic volumes. The short-term impacts of lockdowns on China's air quality have been measured and reported, however, the changes in anthropogenic emissions have not yet been assessed quantitatively, which hinders our understanding of the causes of the air quality changes during COVID-19. Here, for the first time, we report the anthropogenic air pollutant emissions from mainland China during the first eight months of 2020 by using a bottom-up approach based on the near real-time data. The COVID-19 lockdown was estimated to have reduced China's anthropogenic emissions substantially between January and March in 2020, with the largest reductions in February. Emissions of SO2, NOx, CO, NMVOCs, and primary PM2.5 were estimated to have decreased by 29 %, 31 %, 27 %, 26 %, and 21 %, respectively, in February 2020 compared to the same month in 2019. The reductions in anthropogenic emissions were dominated by the industry sector for SO2 and PM2.5 and were contributed approximately equally by the industry and transportation sectors for NOx, CO, and NMVOCs. With the spread of coronavirus controlled, China's anthropogenic emissions rebounded in April and since then returned to the comparable levels of 2019 in August 2020. The provinces in China have presented nearly synchronous decline and rebound in anthropogenic emissions, while Hubei and the provinces surrounding Beijing recovered slower due to the extension of lockdown measures. The reduction ratios of anthropogenic emissions from 2019 to 2020 can be accessed from https://doi.org/10.6084/m9.figshare.c.5214920.v1 (Zheng et al., 2020) by species, month, sector, and province.

Spring Festival and COVID‐19 Lockdown: Disentangling PM Sources in Major Chinese Cities

“…A sudden decline in the meteorologically normalized NO 2 coincided with the start of the CSF in all studied cities in 2015–2019 (Figure ), with an average of −14.1%, ranging from −24.1 ± 2.0% in Hangzhou to −3.9 ± 1.1% in Harbin (Table ). A recent study reported that the CSF effect caused a 20.9% reduction of the NO x emission intensity (Gg/d) in China in 2019 (Zheng et al., 2020), comparable to our estimates of NO 2 in 2019 (14.7 ± 6.5%). On average, O 3 increased by 6.6% (from +1.5 ± 3.4% in Lhasa to +10.0 ± 1.4% in Changchun) (Figure ).…”

“…The declines in NO 2 were strongly related to transportation and industrial emission changes as determined by the changes in anthropogenic emissions in February 2019 in mainland China (Zheng et al., 2020). Such effects of CSF on NO 2 were more substantial for cities with greater vehicle populations (Figure ).…”

Substantial changes in gaseous pollutants and chemical compositions in fine particles in the North China Plain during the COVID-19 lockdown period: anthropogenic vs. meteorological influences

“…The mass concentration of PM 2.5 was determined using an oscillating balance analyzer (TH-2000Z, China) (Wang et al, 2014). The NH 3 concentration and watersoluble ions including sulfate (SO 2− 4 ), nitrate (NO − 3 ), ammonium (NH + 4 ), sodium ion (Na + ), and chloridion (Cl − ) were monitored with a gas and aerosol collector combined with ion chromatography (GAC-IC; TH-PKU-303, China) (Wang et al, 2014;Zheng et al, 2019). Organic carbon (OC) and elemental carbon (EC) were measured using an OC-EC analyzer (model RT-4, Sunset Laboratory Inc., Tigard, Oregon, USA).…”

“…However, both observed NO − 3 and NH + 4 concentrations in Tangshan even showed slight increases, though the NO 2 concentration suffered from a remarkable decrease. It was assumed that the adverse meteorological conditions might be beneficial to the pollutant accumulation (Zheng et al, 2019;. Additionally, the concentrations of nine trace elements were also determined.…”

“…The predominant species in factor 3 included Na + (42 %), K (40 %), OC (35 %), and EC (33 %). K was often regarded as the fingerprint of biomass burning (BB) (Chen et al, 2017;Zheng et al, 2019), whereas the Na + was generally regarded as the tracer of waste incineration (Alam et al, 2019;Durlak et al, 1997). Hence, factor 3 was treated as the BB source.…”