Chemical characteristics and sources of PM2.5 in Hohhot, a semi-arid city in northern China: insight from the COVID-19 lockdown
Open Access
- 19 September 2022
- journal article
- research article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 22 (18), 12153-12166
- https://doi.org/10.5194/acp-22-12153-2022
Abstract
A knowledge gap exists concerning how chemical composition and sources respond to implemented policy control measures for aerosols, particularly in a semi-arid region. To address this, a single year's offline measurement was conducted in Hohhot, a semi-arid city in northern China, to reveal the driving factors of severe air pollution in a semi-arid region and assess the impact of the COVID-19 lockdown measures on chemical characteristics and sources of PM2.5. Organic matter, mineral dust, sulfate and nitrate accounted for 31.5 %, 14.2 %, 13.4 % and 12.3 % of the total PM2.5 mass, respectively. Coal combustion, vehicular emission, crustal source and secondary inorganic aerosols were the main sources of PM2.5 in Hohhot, at 38.3 %, 35.0 %, 13.5 %, and 11.4 %, respectively. Due to the coupling effect of emission reduction and improved atmospheric conditions, the concentration of secondary inorganic components, organic matter and elemental carbon declined substantially from the pre-lockdown (pre-LD) period to the lockdown (LD) and post-lockdown (post-LD) periods. The source contribution of secondary inorganic aerosols increased (from 21.1 % to 37.8 %), whereas the contribution of vehicular emission reduced (from 35.5 % to 4.4 %) due to lockdown measures. The rapid generation of secondary inorganic components caused by unfavorable meteorological conditions during lockdown led to serious pollution. This study elucidates the complex relationship between air quality and environmental policy.Funding Information
- National Natural Science Foundation of China (42167015)
- Natural Science Foundation of Inner Mongolia (2018MS02001)
This publication has 76 references indexed in Scilit:
- Methods for estimating uncertainty in factor analytic solutionsAtmospheric Chemistry and Physics, 2014
- Land use patterns and SO2 and NO2 pollution in Ulaanbaatar, MongoliaEnvironmental Research, 2013
- Chemical composition, diurnal variation and sources of PM2.5 at two industrial sites of South ChinaAtmospheric Pollution Research, 2013
- Characterization, sources and redox activity of fine and coarse particulate matter in Milan, ItalyAtmospheric Environment, 2012
- Spatial and seasonal variability of PM2.5 acidity at two Chinese megacities: insights into the formation of secondary inorganic aerosolsAtmospheric Chemistry and Physics, 2012
- Mineral aerosols from western India: Temporal variability of coarse and fine atmospheric dust and elemental characteristicsAtmospheric Environment, 2009
- Interpretation of organic components from Positive Matrix Factorization of aerosol mass spectrometric dataAtmospheric Chemistry and Physics, 2009
- Characterization and source apportionment of atmospheric organic and elemental carbon during fall and winter of 2003 in Xi'an, ChinaAtmospheric Chemistry and Physics, 2005
- Carbonaceous aerosol in urban and rural European atmospheres: estimation of secondary organic carbon concentrationsAtmospheric Environment, 1999
- Positive matrix factorization: A non‐negative factor model with optimal utilization of error estimates of data valuesEnvironmetrics, 1994