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

Abstract

To investigate the seasonal and spatial variations of ion chemistry of fine particles in Northern Zhejiang Province (NZP), China, one year-long field sampling was conducted at four representative sites (two urban, one suburb, and one rural sites) in both cities of Hangzhou and Ningbo from December 2014 to November 2015. Twelve water soluble inorganic ions (WSII) were characterized in this comprehensive study. The annual average of PM concentration in NZP as overall was 66.2 ± 37.7 μg m, and urban sites in NZP were observed with more severe PM pollution than the suburban and rural sites. The annual average concentration of total WSII at four sampling sites in NZP was 29.1 ± 19.9 μg m, dominated by SO (10.3 μg m), and followed by NO (8.9 μg m), NH (6.6 μg m), Cl (1.3 μg m) and K (0.7 μg m). Among all cations, NH was the predominant neutralizing ion with the highest neutralization factor (NF), while the remaining cations showed limited neutralization capacity. The highest and lowest sulfur oxidation ratio (SOR) values in this region were found in summer and winter, respectively; while the seasonal patterns for nitrogen oxidation ratio (NOR) were opposite to that of SOR. Principal component analysis (PCA) showed that the significant sources of WSII in NZP were industrial emissions, biomass burning, and formation of secondary inorganic aerosols. In addition, contribution from transboundary transport of polluted aerosols was also confirmed from the assessment through air mass backward trajectory analysis.

Characteristics of fine particulate matter and its sources in an industrialized coastal city, Ningbo, Yangtze River Delta, China

“…Cl − is considered to be an important ion contributing to the formation of PM 2.5 in coastal cities (Xu et al, 2017). Cl − showed the high concentration in this study, which may be attributed to both sea source and anthropogenic emission.…”

“…Factor 4 had a significant contribution of Cl − , accounting for 7.6% of PM 2.5 . In addition to marine source (seawater), coal combustion and chlor-alkli chemical industry could be identified as the main source for Clin this study (Xu et al, 2017;Liu et al, 2017).…”

“…5. It might be because that secondary inorganic ions such as NO 3are generated through both homogeneous and heterogeneous reactions of gaseous precursors including SO 2 and NO x (Xu et al, 2017). SO 4 2concentrations ranged from 3.6 to 25.0 μg/m 3 with an average of 11.2 μg/m 3 .…”

Application of Fuzzy Optimization Model Based on Entropy Weight Method in Atmospheric Quality Evaluation: A Case Study of Zhejiang Province, China

“…Xu et al selected four representative locations (two cities, one suburb site and one rural site) in Hangzhou and Ningbo from December 2014 to November 2015 in order to study the seasonal and spatial variation in terms of fine particle pollution in Zhejiang Province. With help of the Principal Component Analysis (PCA) method, they found that industrial emissions, biomass burning, and formation of secondary inorganic aerosols are the major sources of fine particles in Zhejiang Province [28]. Fu et al studied the potential correlation between conjunctivitis and air pollution based on the air pollutant data from the Environmental Protection Department of Zhejiang Province from 1 July 2014 to 30 June 2016 and data of 9737 outpatient visits for conjunctivitis at the Eye Center of the Second Affiliated Hospital of Zhejiang University School of Medicine.…”

“…(1) By constructing the six major pollutants defined by China's air quality standards, we have evaluated the air quality of Zhejiang Province more comprehensively than the existing research. In similar studies of air quality in Zhejiang Province, scholars often use particulate pollutants as research objects [27,28,78]. Then, few research works contain the six major pollutants.…”