Aerosol composition and sources during high and low pollution periods in Ningbo, China

Abstract

Due to the rapid industrialization of the Yangtze River Delta (YRD) region in China, heavy air pollution episodes have occurred frequently over the past five years which are of great concern due to their environmental and health impacts. To investigate the chemical characteristics of the highly polluted aerosols in this region, a sampling campaign had been conducted in Ningbo from 3 December 2012 to 27 June 2013, during which a month long high pollution episode had been captured. Daily average PM2.5 concentrations during high and low pollution periods were 111 μg m-³ and 53 μg m-³, respectively. The most polluted day was 8 January 2013 with a PM2.5 concentration up to 175 μg m-3. To understand the origin of the highly polluted aerosols, meteorological conditions, air mass backward trajectories, distribution of fire spots in surrounding areas and various categories of aerosol pollutants were analysed, including trace metals, inorganic species, PAHs and anhydrosugars. Total metal concentrations were 3.8 and 1.6 μg m-³ for the high and low pollution episodes, respectively, accounting for 3.4% and 3.1% of the total PM2.5 mass. Total concentrations of ionic species accounted for more than 50.0% of the PM2.5 by mass, with dominant ions (nitrate, sulphate, ammonium) accounting for over 42.0% of the PM2.5 mass concentrations in both periods. During the high pollution episode, enhanced Cd-Pb and biomarker (levoglucosan, mannosan) levels indicated the contributions from coal combustion, traffic and biomass burning to fine aerosol PM2.5. The average diagnostic ratio of Fla/(Fla+Pyr) was 0.54 in high pollution episode, which was intermediate between that for wood (>0.50) and coal combustion (0.58). BaP/Bpe was 0.49 and 0.30 for the highly and lightly polluted aerosols respectively, associated with the significant non-traffic emissions (<0.60). In addition, stagnant weather conditions during the high pollution period and long-range transport of air masses from heavy industries and biomass burning from northern China to Ningbo could be considered as the main factors for the formation of the aerosols during high pollution period.

Temporal and spatial variation in major ion chemistry and source identification of secondary inorganic aerosols in Northern Zhejiang Province, China

“…In total, 6 anions (F -, Cl -, NO2 -, NO3 -, PO4 3-, SO4 2-) and 6 cations (Li + , Na + , NH4 + , K + , Mg 2+ , Ca 2+ ) were investigated by Ion Chromatograph (ICS-1600, Dionex, USA). Detailed information about the detection system and methods could be found elsewhere (Xu et al, 2016b).…”

The Research on Air Pollution Laws in Guanzhong Urban Agglomeration Based on High Frequency AQI Data

“…Kassomenos P, Vardoulakis S and Chaloulakou analyzed the sources and seasonal characteristics of particulate pollution in three European cities [3]; Kimbrough Sue, Baldauf Richard W and Hagler Gayle S W had the analysis of the impact of seasonal changes on local air quality in Las Vegas city [4]; Zhou HJ, He J and Zhao BY analyzed the distribution characteristics of the particulate matter in Baotou city in the pollution season [5]; Xu JS, Xu HH and Xiao H have made the research of composition characteristics and sources of the aerosol in varying degrees of pollution period in Ningbo city [6]. In terms of methodology, descriptive statistics, correlation analysis and principal component analysis have been widely used to study the air pollution problem.…”

Regional severe particle pollution and its association with synoptic weather patterns in the Yangtze River Delta region, China

“…In particular, severe particle pollution episodes are widely recognized as one of the major air pollution issues in the YRD (Fu et al, 2008(Fu et al, , 2010Deng et al, 2011;Huang et al, 2012;Kang et al, 2013;Kong et al, 2013;Wang et al, 2013Wang et al, , 2014Wang et al, , 2015Fu et al, 2014;Feng et al, 2015;Zheng et al, 2015b;Xu et al, 2016;Ming et al, 2017). Thus, many studies have been conducted to determine the contamination status (Fu et al, 2010;Kang et al, 2013;Wang et al, 2013Wang et al, , 2015Feng et al, 2015;Ming et al, 2017), possible source (Fu et al, 2010(Fu et al, , 2014Kong et al, 2013;Wang et al, 2013Wang et al, , 2014Xu et al, 2016), and causes or features (Fu et al, 2008(Fu et al, , 2010Huang et al, 2012;Wang et al, 2015;Zheng et al, 2015a) of these episodes. However, studies that have attempted to determine how particle pollution in the YRD is associated with synoptic weather patterns are still quite limited.…”

“…In recent years, similar to other megacity clusters in China, such as the Beijing-Tianjin-Hebei (BTH) region (He et al, 2001;Chan and Yao, 2008;Ji et al, 2012;Zhao et al, 2013;Zheng et al, 2015a) and the Pearl River Delta (PRD) region (Ho et al, 2003;Chan and Yao, 2008;Xie et al, 2016c;Zhu et al, 2017), the YRD has suffered from severe air pollution problems caused by an increasing population, urban expansion, and industrialization (Chan and Yao, 2008;Fu et al, 2008Fu et al, , 2010Fu et al, , 2014Deng et al, 2011;Li et al, 2011;Huang et al, 2012;Kang et al, 2013;Wang et al, 2013Wang et al, , 2014Wang et al, , 2015Xie et al, 2014Xie et al, , 2016aXie et al, , b, 2017Feng et al, 2015;Zheng et al, 2015b;Shu et al, 2016;Xu et al, 2016;Ming et al, 2017). In particular, severe particle pollution episodes are widely recognized as one of the major air pollution issues in the YRD (Fu et al, 2008(Fu et al, , 2010Deng et al, 2011;Huang et al, 2012;Kang et al, 2013;Kong et al, 2013;Wang et al, 2013Wang et al, , 2014Wang et al, , 2015Fu et al, 2014;Feng et al, 2015;…”