A Long-lasting Winter Haze Episode in Xiangyang, Central China: Pollution Characteristics, Chemical Composition, and Health Risk Assessment

Huimeng Jiang,Zuwu Wang,Han Xiao,Jian Liu,Hairong Cheng,Tao Wang,He Song

doi:10.4209/aaqr.2020.02.0068

Huimeng Jiang, Zuwu Wang + Show 5 more

Open Access

https://doi.org/10.4209/aaqr.2020.02.0068

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Abstract

ABSTRACT This study investigated the characteristics and chemical composition of PM2.5 during a long-lasting winter haze episode (Jan. 13–24, 2018) in Xiangyang of central China. The average daily concentration of the PM2.5 equaled 169.29 ± 56.98 µg m–3, with water-soluble inorganic ions (WSIIs), organic carbon (OC), elemental carbon (EC), and trace elements accounting for 111.45 ± 44.62, 20.74 ± 6.79, 6.48 ± 1.79, and 10.53 ± 3.84 µg m–3, respectively. The OC/EC ratios indicated mixed contributions from intensive traffic emission and secondary formation, and the estimated concentrations for the primary organic carbon (POC) and the secondary organic carbon (SOC) increased with the level of pollution. POC dominated the OC during mild and moderate pollution, whereas SOC dominated it during severe pollution. A strong positive correlation was found between the enrichment factor (EF) and geo-accumulation index (IGeo) values, which were used to assess the contamination level of PM2.5-bound metal(loid)s. A health risk assessment, which was conducted to examine the non-carcinogenic and carcinogenic risks of the PM2.5-bound metal(loid)s, found that As, Cr, Pb, and Sb posed potential non-carcinogenic risks to both children and adults and that two of these elements, As and Pb, also posed potential carcinogenic risks. The total non-carcinogenic and carcinogenic risks from the PM2.5-bound metal(loid)s were slightly higher for adults (3.07 × 103 and 3.78 × 10–3) than children (2.71 × 103 and 2.99 × 10–3) and depended on the concentrations of the metal(loid)s rather than the level of pollution. Thus, the public and the government should implement appropriate measures to mitigate the health risks posed by PM2.5-bound metal(loid)s during winter haze episodes in Xiangyang.

Highlights

Fine particulate matter (PM2.5) has attracted increased attention by the public and government over the past years, due to its significant impact on global climate change, atmospheric visibility degradation, cloud processes, and public health risk (Huang et al, 2014)
These air masses originated from Inner Mongolia, passed through Hebei and Shanxi Province, turned a corner in Shandong Province, and approached the sampling site through Henan Province with higher transport speeds (4.74 m s–1) than the average wind speed (3.02 m s–1) obtained from Hubei Meteorological Service during the whole winter haze episode (Fig. 3)
The high PM2.5 concentrations during episodes of severe pollution may have been partially due to the arrival of air masses from the NNW–NE, whereas the lower concentrations during periods of less pollution may have been influenced by air masses from the NW–NE or NW–SW

Summary

Introduction

Fine particulate matter (PM2.5) has attracted increased attention by the public and government over the past years, due to its significant impact on global climate change, atmospheric visibility degradation, cloud processes, and public health risk (Huang et al, 2014). PM2.5 is directly emitted from emission sources, including industrial process, coal-fired power plant, vehicle exhaust, agricultural biomass burning, crustal dust. It is indirectly formed through gas-to-particle conversions of volatile organic compounds (VOCs) and gaseous precursors (SO2, NOx and NH3) (Liu et al, 2016a). Xiangyang (31°13ʹ–32°38ʹN, 110°45ʹ–113°47ʹE) occupies a 19,800 km area and has more than 6 million people. It lies in the northwest of Hubei Province and in the middle reaches.

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