Characterization and Source Apportionment of Fine Particles during a Heavy Pollution Episode over the Yangtze River Delta, China

Li Xia,Junlin An,Honglei Wang,Hanqing Kang,Bin Zhu

doi:10.3390/atmos11070720

Abstract

Regional-scale field observations of fine particles (PM2.5) were carried out at urban, suburban and regional background sites across the Yangtze River Delta (YRD) from 15–30 January 2015. The coefficients of divergence (CD) values reveal the similarity of dataset at the three sites. The PM2.5 concentrations and meteorological data exhibit temporal synchronization. From January 15 to 26, the YRD experienced severe PM2.5 pollution resulting from a cold front moving through and high-pressure control. Then, a 4-day intermittent rain event from 27–30 January significantly scavenged PM2.5. For the chemical components in PM2.5, secondary inorganic ions were dominant, and they accounted for larger proportions at the urban and suburban sites than at the regional background site. The OC/EC ratios were higher in daytime than at night, and were lower on polluted days than on clean (rainy) days. The principal sources of PM2.5 were secondary nitrate (38%) and sulfate (23%) formation, biomass burning (14%), and marine source (8%). Marine (16%) and sulfate (30%) sources were enhanced on clean (rainy) days, indicating the notable effect of marine air masses on PM2.5 chemical components. The open burning source contribution at the regional site was the largest during the polluted period because more air masses arrived from combustion zones.

Highlights

Over the last several decades, with rapid economic growth and urbanization [1], megacities and city clusters [2] in China have been experiencing severe air pollution [3]
Field observations of the ambient particle pollution over the Yangtze River Delta (YRD) have been conducted in previous studies, which mostly focus on the chemical properties, formation mechanisms, source apportionment, etc
We report the results results obtained from simultaneous field observations carried out in NJ (a suburban site, industrial obtained from simultaneous field observations carried out in NJ, Suzhou (SZ, an urban site, residential area) and LA, Suzhou (SZ, an urban site, residential area) and LA mountain area) from January 15–30, 2015

Summary

Introduction

Over the last several decades, with rapid economic growth and urbanization [1], megacities and city clusters [2] in China have been experiencing severe air pollution [3]. In addition to the intensive anthropogenic emission, PM2.5 pollutions in China are mainly contributed by adverse meteorological conditions, secondary aerosol formation, and regional transport [10,11]. The Yangtze River Delta (YRD), located in eastern China, is one of the densely populated city clusters with the highest economic development in China. Field observations of the ambient particle pollution over the YRD have been conducted in previous studies, which mostly focus on the chemical properties, formation mechanisms, source apportionment, etc.

Methods

Results

Conclusion