Seasonal variations in composition and sources of  atmospheric ultrafine particles in urban Beijing  based on near-continuous measurements

X. Li; X. Li; Y. Chen; Y. Li; R. Cai; Y. Li; C. Deng; J. Wu; C. Yan; C. Yan; H. Cheng; Y. Liu; M. Kulmala; M. Kulmala; J. Hao; J. N. Smith; J. Jiang

doi:10.5194/acp-23-14801-2023

Atmospheric Chemistry and Physics (Dec 2023)

Seasonal variations in composition and sources of atmospheric ultrafine particles in urban Beijing based on near-continuous measurements

X. Li,
X. Li,
Y. Chen,
Y. Li,
R. Cai,
Y. Li,
C. Deng,
J. Wu,
C. Yan,
C. Yan,
H. Cheng,
Y. Liu,
M. Kulmala,
M. Kulmala,
J. Hao,
J. N. Smith,
J. Jiang

Affiliations

X. Li: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
X. Li: School of Resources and Environmental Sciences, Wuhan University, 430072 Wuhan, China
Y. Chen: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
Y. Li: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
R. Cai: Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
Y. Li: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
C. Deng: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
J. Wu: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
C. Yan: Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
C. Yan: Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, 100029 Beijing, China
H. Cheng: School of Resources and Environmental Sciences, Wuhan University, 430072 Wuhan, China
Y. Liu: Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, 100029 Beijing, China
M. Kulmala: Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
M. Kulmala: Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, 100029 Beijing, China
J. Hao: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China
J. N. Smith: Chemistry Department, University of California, Irvine, CA 92697, USA
J. Jiang: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China

DOI: https://doi.org/10.5194/acp-23-14801-2023
Journal volume & issue: Vol. 23
pp. 14801 – 14812

Abstract

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Understanding the composition and sources of atmospheric ultrafine particles (UFPs) is essential in evaluating their exposure risks. It requires long-term measurements with high time resolution, which are scarce to date. We performed near-continuous measurements of UFP composition during four seasons in urban Beijing using a thermal desorption chemical ionization mass spectrometer, accompanied by real-time size distribution measurements. We found that UFPs in urban Beijing are dominated by organic components, varying seasonally from 68 % to 81 %. CHO organics (i.e., molecules containing carbon, hydrogen, and oxygen) are the most abundant in summer, while sulfur-containing organics, some nitrogen-containing organics, nitrate, and chloride are the most abundant in winter. With the increase of particle diameter, the contribution of CHO organics decreases, while that of sulfur-containing and nitrogen-containing organics, nitrate, and chloride increases. Source apportionment analysis of the UFP organics indicates contributions from cooking and vehicle sources, photooxidation sources enriched in CHO organics, and aqueous/heterogeneous sources enriched in nitrogen- and sulfur-containing organics. The increased contributions of cooking, vehicle, and photooxidation components are usually accompanied by simultaneous increases in UFP number concentrations related to cooking emission, vehicle emission, and new particle formation, respectively, while the increased contribution of the aqueous/heterogeneous composition is usually accompanied by the growth of UFP mode diameters. The highest UFP number concentrations in winter are due to the strongest new particle formation, the strongest local primary particle number emissions, and the slowest condensational growth of UFPs to larger sizes. This study provides a comprehensive understanding of urban UFP composition and sources and offers valuable datasets for the evaluation of UFP exposure risks.

Published in Atmospheric Chemistry and Physics

ISSN: 1680-7316 (Print); 1680-7324 (Online)
Publisher: Copernicus Publications
Country of publisher: Germany
LCC subjects: Science: Physics; Science: Chemistry
Website: http://www.atmospheric-chemistry-and-physics.net/

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