Characteristics and Sources of Heavy Metals in PM2.5 during a Typical Haze Episode in Rural and Urban Areas in Taiyuan, China

Kankan Liu,Ping Song,Qingmin Shang,Chanyuan Ma,Changyuan Wan,Liyuan Cao

doi:10.3390/atmos9010002

Kankan Liu, Ping Song + Show 4 more

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https://doi.org/10.3390/atmos9010002

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Abstract

PM2.5 samples were collected in the rural and urban areas of Taiyuan, China during a typical haze episode and the heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd and Pb) in PM2.5 were analyzed. The haze was characterized by start-up stage with a daily mean PM2.5 of 149.34 ± 52.33 and 146.73 ± 18.96 μg m−3 in the rural and urban sites, respectively, a peak stage (288.20 ± 12.43 and 323.44 ± 5.23 μg m−3), and a weakening stage (226.59 ± 12.43 and 195.60 ± 2.93 μg m−3). The concentrations of PM2.5 in the rural and urban sites in the peak stage were 5.9 and 5.5 times higher than those in the normal stage, respectively. The order of concentrations of heavy metals in PM2.5 at the rural and urban sites were the same and are listed as follows: Zn > Pb > Mn > Cr > Cu > Ni > Cd > As. Pb at the rural site, As at the urban site, and Cd at the both sites failed to meet the air quality standard. The concentrations of Pb and Zn were higher at the rural site than those at the urban site. Principal component analysis indicated that the main sources of heavy metals for the rural area were raw coal combustion and soil/road dust, and for the urban area were coal combustion/industrial emissions, road/soil dust, and vehicle emissions/oil combustion.

Highlights

Large-scale regions in North China are suffering from severe haze episodes [1,2,3,4,5], which are essentially caused by fine particles with aerodynamic diameter less than 2.5 μm (PM2.5 ) [3,6,7]
Chronic exposure to PM2.5 is associated with a wide range of diseases [4,10], mainly since atmospheric PM2.5 can carry varieties of pathogenic components, such as heavy metals, viruses, and bacteria
The heating period in the urban region is usually five months, while the raw-coal burning in rural areas routinely lasts more than six months for heating and almost the whole year for cooking

Summary

Introduction

Large-scale regions in North China are suffering from severe haze episodes [1,2,3,4,5], which are essentially caused by fine particles with aerodynamic diameter less than 2.5 μm (PM2.5 ) [3,6,7].This has attracted great scientific and public attention [8,9,10,11,12,13]. Large-scale regions in North China are suffering from severe haze episodes [1,2,3,4,5], which are essentially caused by fine particles with aerodynamic diameter less than 2.5 μm (PM2.5 ) [3,6,7]. Chronic exposure to PM2.5 is associated with a wide range of diseases [4,10], mainly since atmospheric PM2.5 can carry varieties of pathogenic components, such as heavy metals, viruses, and bacteria. Previous studies have demonstrated the adverse health effect relationship between particulate matter exposure and toxic heavy metal elements [22,23,24,25]

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