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Taiwan Strait is a special channel for subtropical East Asian Monsoon and its western coast is an important economic zone in China. In this study, a suburban site in the city of Xiamen on the western coast of Taiwan Strait was selected for fine aerosol study to improve the understanding of air pollution sources in this region. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and an Aethalometer were deployed to measure fine aerosol composition with a time resolution of 5 min from May 1 to 18, 2015. The average mass concentration of PM1 was 46.2 ± 26.3 μg/m3 for the entire campaign. Organics (28.3%), sulfate (24.9%), and nitrate (20.6%) were the major components in the fine particles, followed by ammonium, black carbon (BC), and chloride. Evolution of nitrate concentration and size distribution indicated that local NOx emissions played a key role in high fine particle pollution in Xiamen. In addition, organic nitrate was found to account for 9.0%–13.8% of the total measured nitrate. Positive Matrix Factorization (PMF) conducted with high-resolution organic mass spectra dataset differentiated the organic aerosol into three components, including a hydrocarbon-like organic aerosol (HOA) and two oxygenated organic aerosols (SV-OOA and LV-OOA), which on average accounted for 27.6%, 28.8%, and 43.6% of the total organic mass, respectively. The relationship between the mass concentration of submicron particle species and wind further confirmed that all major fine particle species were influenced by both strong local emissions in the southeastern area of Xiamen and regional transport through the Taiwan Strait. [ABSTRACT FROM AUTHOR]

Abstract: The carbonaceous species and potassium in PM2.5 were measured in the coastal urban agglomeration in the Western Taiwan Strait Region (WTSR), China in November 2010, January, April and August 2011, with the objectives to understand the spatiotemporal distribution of carbonaceous aerosols and to estimate the contribution from biomass burning and non-biomass burning to carbonaceous aerosols in this region. The average concentrations of organic carbon (OC) and elemental carbon (EC) in PM2.5 at the urban sites in the WTSR were 12.7±4.3μgm−3 and 2.3±0.9μgm−3, respectively, with the maxima in January/April and minima in August for most sites. It was found that the OC concentrations on no-rain days were higher than those on rainy days due to precipitation scavenging. Total carbonaceous aerosol (OC×1.6+EC) made up 32.1±15.6% of PM2.5. High OC/EC ratios (average 5.8) indicated the formation of secondary organic carbon (SOC), which contributed higher to the OC in January than that in August. Strong correlations were observed between biomass-burning potassium (K+ bb) and OC (R 2 =0.56, p <0.01) and EC (R 2 =0.54, p <0.01) in November. It was roughly estimated that 42.1±15.1% of total carbon (TC) in November were attributed to biomass burning, which suggested that non-biomass burning was the main source of carbonaceous materials in aerosols in the coastal urban agglomeration in the WTSR. [Copyright &y& Elsevier]