Characteristics and sources of PM2.5 with focus on two severe pollution events in a coastal city of Qingdao, China

Yang Gao; Huayao Shan; Shaoqing Zhang; Lifang Sheng; Jianping Li; Junxi Zhang; Mingchen Ma; He Meng; Kun Luo; Huiwang Gao; Xiaohong Yao

doi:10.1016/j.chemosphere.2020.125861

Characteristics and sources of PM_2.5 with focus on two severe pollution events in a coastal city of Qingdao, China

Chemosphere. 2020 May:247:125861. doi: 10.1016/j.chemosphere.2020.125861. Epub 2020 Jan 7.

Authors

Yang Gao¹, Huayao Shan², Shaoqing Zhang³, Lifang Sheng⁴, Jianping Li⁵, Junxi Zhang⁶, Mingchen Ma², He Meng⁷, Kun Luo⁶, Huiwang Gao⁸, Xiaohong Yao⁹

Affiliations

¹ Key Laboratory of Marine Environment and Ecology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China. Electronic address: yanggao@ouc.edu.cn.
² Key Laboratory of Marine Environment and Ecology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao, 266100, China.
³ Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Key Laboratory of Physical Oceanography, Ministry of Education/Institute for Advanced Ocean Study/Frontiers Science Center for Deep Ocean Multispheres and Earth System (DOMES), Ocean University of China, Qingdao, 266100, China; International Laboratory for High-Resolution Earth System Prediction (iHESP), Qingdao, 266237, China; College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, 266100, China.
⁴ College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, 266100, China; Ocean-Atmosphere Interaction and Climate Laboratory, Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao, 266100, China.
⁵ Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Key Laboratory of Physical Oceanography, Ministry of Education/Institute for Advanced Ocean Study/Frontiers Science Center for Deep Ocean Multispheres and Earth System (DOMES), Ocean University of China, Qingdao, 266100, China.
⁶ State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China.
⁷ Qingdao Environmental Monitoring Station, Qingdao, 266003, China.
⁸ Key Laboratory of Marine Environment and Ecology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
⁹ Key Laboratory of Marine Environment and Ecology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China. Electronic address: xhyao@ouc.edu.cn.

PMID: 31931317
DOI: 10.1016/j.chemosphere.2020.125861

Abstract

In this study, the seasonal mean PM_2.5 concentration in Qingdao, a coastal city, during 2014-2018 was first analyzed and the winter, in particular of 2015, showed the highest concentration. To elucidate the sources and control factors of PM_2.5, three dimensional model Weather Research and Forecasting (WRF), Community Multiscale Air Quality model (CMAQ), as well as Flexible Particle model (FLEXPART), were used. During December 2015 and January 2016, modeling results showed that the mean contribution to PM_2.5 mass concentrations from local emissions in Qingdao was 25%, and the transport from north and west accounted for almost half. Over the two episodically polluted periods (29-31 December 2015; 15-17 January 2016), the local emissions in Qingdao surprisingly contributed to only 18% and 24% to PM_2.5 mass concentrations, respectively, indicating the dominant contributions from other regions, such as areas outside Qingdao in Shandong and Beijing-Tianjin-Hebei (BTH). The results show the sources region and contribution may vary remarkably along with the change in the pathways of the air parcel, inferred by the FLEXPART, while the near-surface PM_2.5 enhancement is largely caused by downward vertical advection and enhanced aerosol chemistry reactions, accompanied by simultaneous drop in the boundary layer height. This study also reveals that the transport contribution is sensitive to the air parcel trajectories. We, therefore, recommend the efficient emission control based on transport trajectories in short-term air quality improvement in Qingdao.

Keywords: Air parcel trajectories; CMAQ; FLEXPART; PM(2.5); WRF.

MeSH terms

Aerosols
Air Pollutants / analysis*
Air Pollution / analysis*
China
Cities
Environmental Monitoring / methods*
Models, Theoretical*
Particulate Matter / analysis*
Seasons
Vehicle Emissions / analysis*
Weather

Substances

Aerosols
Air Pollutants
Particulate Matter
Vehicle Emissions