Dataset Information

Weakened Aerosol-PBL Interaction During COVID-19 Lockdown in Northern China.

ABSTRACT: Anthropogenic emissions were greatly constrained during COVID-19 lockdown in China. Nevertheless, observations still showed high loadings of fine particles (PM_2.5) over northern China with secondary aerosols increasing by 15 ?g/m³ yet a ?10% drop in light-absorbing black carbon (BC). Such a chemical transition in aerosol composition tended to make the atmosphere more scattering, indicated by satellite-retrieved aerosol absorption optical depth falling by 60%. Comparison between weather forecast and radiosonde observations illustrated that, without upper-level heating induced by BC, the stabilized stratification diminished, which was conducive for planetary boundary layer (PBL) mixing and thus near-surface pollution dispersion. Furthermore, coupled dynamic-chemistry simulations estimated that emission reduction during the lockdown weakened aerosol-PBL interaction and thus a reduction of 25 ?g/m³ (?50%) in PM_2.5 enhancement. Based on the unique natural experiment, this work observationally confirmed and numerically quantified the importance of BC-induced meteorological feedback, further highlighting the priority of BC control in haze mitigation.

SUBMITTER: Wang Z

PROVIDER: S-EPMC7883207 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Weakened Aerosol-PBL Interaction During COVID-19 Lockdown in Northern China.

Wang Zilin Z Huang Xin X Ding Ke K Ren Chuanhua C Cao Lu L Zhou Derong D Gao Jian J Ding Aijun A

Geophysical research letters 20210202 3

Anthropogenic emissions were greatly constrained during COVID-19 lockdown in China. Nevertheless, observations still showed high loadings of fine particles (PM<sub>2.5</sub>) over northern China with secondary aerosols increasing by 15 μg/m<sup>3</sup> yet a ∼10% drop in light-absorbing black carbon (BC). Such a chemical transition in aerosol composition tended to make the atmosphere more scattering, indicated by satellite-retrieved aerosol absorption optical depth falling by 60%. Comparison bet ...[more]

PMID: 33612879

Similar Datasets

Project description:To eliminate the spread of a novel coronavirus breaking out in the end of 2019 (COVID-19), the Chinese government has implemented a nationwide lockdown policy after the Chinese lunar New Year of 2020, resulting in a sharp reduction in air pollutant emissions. To investigate the impact of the lockdown on aerosol chemistry, the number fraction, size distribution and formation process of oxalic acid (C2) containing particles and its precursors were studied using a single particle aerosol mass spectrometer (SPAMS) at the urban site of Liaocheng in the North China Plain (NCP). Our results showed that five air pollutants (i.e., PM2.5, PM10, SO2, NO2, and CO) decreased by 30.0-59.8% during the lockdown compared to those before the lockdown, while O3 increased by 63.9% during the lockdown mainly due to the inefficient titration effect of O3 via NO reduction. The increased O3 concentration can boost the atmospheric oxidizing capacity and further enhance the formation of secondary organic aerosols, thereby significantly enhancing the C2 particles and its precursors as observed during the lockdown. Before the lockdown, C2 particles were significantly originated from biomass burning emissions and their subsequent aqueous-phase oxidation. The hourly variation patterns and correlation analysis before the lockdown suggested that relative humidity (RH) and aerosol liquid water content (ALWC) played a key role in the formation of C2 particles and the increased aerosol acidity can promote the conversion of precursors such as glyoxal (Gly) and methyglyoxal (mGly) into C2 particles in the aqueous phase. RH and ALWC decreased sharply but O3 concentration and solar radiation increased remarkably during the lockdown, the O3-dominated photochemical pathways played an important role in the formation of C2 particles in which aerosol acidity was ineffective. Our study indicated that air pollution treatment sponges on a joint-control and balanced strategy for controlling numerous pollutants.

Dataset Information

Weakened Aerosol-PBL Interaction During COVID-19 Lockdown in Northern China.

Publications

Weakened Aerosol-PBL Interaction During COVID-19 Lockdown in Northern China.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets