In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 11 ( 2023-06-07), p. 6217-6240
Abstract:
Abstract. The unprecedented lockdown of human activities during the
COVID-19 pandemic has significantly influenced social life in China.
However, understanding the impact of this unique event on the emissions
of different species is still insufficient, prohibiting the proper
assessment of the environmental impacts of COVID-19 restrictions. Here we
developed a multi-air-pollutant inversion system to simultaneously estimate
the emissions of NOx, SO2, CO, PM2.5 and PM10 in China
during COVID-19 restrictions with high temporal (daily) and horizontal
(15 km) resolutions. Subsequently, contributions of emission changes versus
meteorological variations during the COVID-19 lockdown were separated and
quantified. The results demonstrated that the inversion system effectively
reproduced the actual emission variations in multi-air pollutants in China
during different periods of COVID-19 lockdown, which indicate that the
lockdown is largely a nationwide road traffic control measure with NOx
emissions decreasing substantially by ∼40 %. However,
emissions of other air pollutants were found to only decrease by
∼10 % because power generation and heavy industrial
processes were not halted during lockdown, and residential activities may
actually have increased due to the stay-at-home orders. Consequently,
although obvious reductions of PM2.5 concentrations occurred over the North
China Plain (NCP) during the lockdown period, the emission change only accounted
for 8.6 % of PM2.5 reductions and even led to substantial increases
in O3. The meteorological variation instead dominated the changes in
PM2.5 concentrations over the NCP, which contributed 90 % of the
PM2.5 reductions over most parts of the NCP region. Meanwhile, our results
suggest that the local stagnant meteorological conditions, together with
inefficient reductions of PM2.5 emissions, were the main drivers of the
unexpected PM2.5 pollution in Beijing during the lockdown period. These
results highlighted that traffic control as a separate pollution control
measure has limited effects on the coordinated control of O3 and
PM2.5 concentrations under current complex air pollution conditions in
China. More comprehensive and balanced regulations for multiple precursors
from different sectors are required to address O3 and PM2.5
pollution in China.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-6217-2023
DOI:
10.5194/acp-23-6217-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
