Real-time geochemistry of urban aerosol during a heavy dust episode by single-particle aerosol mass spectrometer: Spatio-temporal variability, mixing state and spectral distribution--颗粒学报PARTICUOLOGY

Shen, L., Hao, F., Gao, M., Wang, H., Zhu, B., Gao, J., . . . Xie, F. (2020). Real-time geochemistry of urban aerosol during a heavy dust episode by single-particle aerosol mass spectrometer: Spatio-temporal variability, mixing state and spectral distribution. Particuology, 53, 197-207. https://doi.org/10.1016/j.partic.2020.02.001

Real-time geochemistry of urban aerosol during a heavy dust episode by single-particle aerosol mass spectrometer: Spatio-temporal variability, mixing state and spectral distribution

Lijuan Shen ^a, Feng Hao ^b, Meng Gao ^c, Honglei Wang ^{a d}^*, Bin Zhu ^a, Jimei Gao ^b, Yufei Cheng ^b, Fei Xie ^b

a Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science & Technology, Nanjing 210044, China
b Environmental Monitoring Centre of Inner Mongolia Autonomous Region, Hohhot 010090, China
c Department of Geography, Hong Kong Baptist University, Hong Kong, China
d State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

10.1016/j.partic.2020.02.001

Volume 53, December 2020, Pages 197-207

Received 25 October 2019, Revised 23 January 2020, Accepted 2 February 2020, Available online 9 April 2020, Version of Record 16 December 2020.

E-mail: hongleiwang@nuist.edu.cn

Highlights

• SPAMS were simultaneously observed in Hohhot and Nanjing.

• Dust intensity (impacted time) weakened (lengthened) with extension of transport distance.

• Spectrum peak was 0.12 μm larger in the dust episode of Nanjing.

• Proportions of EC-secondary and EC-nitrate particles decreased in the dust episode.

Abstract

A heavy dust episode occurred from May 3 to 8, 2017 in China, with an influenced area exceeding 1.63 million km². In this work, the mixing state of aerosols and their spectral distributions were simultaneously observed in the sand source region of Hohhot and the long-range dust transport region of Nanjing by using a single-particle aerosol mass spectrometer (SPAMS). The duration time of this dust episode was 37–40 h in Hohhot and prolonged to 51–104 h in Nanjing. Totals of 336,135 (Hohhot) and 235,840 (Nanjing) particles in PM_2.5 were successfully ionized to identify 10 main particle classes. During this episode, aerosol particles including OCEC (30.65%), K (22.42%), K-CN (17.03%), sodium (9.46%), heavy metal (8.96%), EC-sulfate (3.46%) and Al (3.22%) were prevailing in Hohhot and were dominated by EC-sulfate (22.26%), OCEC (15.21%), heavy metal (11.96%), K (13.68%), sodium (12.27%), Al (10.54%) and EC (9.02%) in Nanjing. The spectral distribution peaked at 0.66 μm during the dust episode in Nanjing, 0.12 μm larger than the peak size in the non-dust episode. Strong signals at −62[NO₃]⁻ and −61[HCO₃]⁻/−61[C₅H]⁻ for aerosol particles were observed in Hohhot and Nanjing respectively. The proportions of K-CN, sodium, heavy mental, OCEC and EC-sulfate particles in the dust episode of Hohhot were 2.75, 1.41, 1.80, 1.22 and 1.28 times as large as the values in the non-dust episode. For Nanjing, the fractions of EC-sulfate, EC, Al particles in the dust episode were 10.55, 4.65 and 1.46 times higher than values in the non-dust episode. The proportions of EC-secondary and EC-nitrate particles were found to decrease in the dust episode in the two regions.

Graphical abstract

Keywords

Dust storm; Mixing state; Spectral distribution; Aerosol; SPAMS

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