Inter-comparison of Chemical Composition and Originality of Atmospheric PM10 at Coastal Regions and Offshore Islands in the Subtropical East Asia

Abstract

Inter-comparison on the chemical characteristics, spatiotemporal variation, and source originality of atmosphere PM 10 at the coastal regions and offshore islands of subtropical region in East Asia was investigated. A total of six sampling sites including three coastal and three island sites over the Minjiang estuary were selected for simultaneously manually sampling PM 10 to investigate the differences of coastal and island PM 10 concentration, chemical properties, and emission sources. After sampling, an ion chromatographer (IC) was used to analyze the concentration of major anions (F − , Cl − , SO 4 2− , and NO 3 − ) and cations (NH 4 + , K + , Na + , Ca 2+ and Mg 2+ ). The metallic elements (Na, Ca, Al, Fe, Mg, K, Zn, Cr, Ti, Mn, Ni, Pb, and Cd) of PM 10 were measured with an inductively coupled plasma-atomic emission spectrometer (ICP-AES). The carbonaceous contents, including elemental, organic, and total carbons (OC, EC, and TC), of PM 10 were analyzed with an elemental analyzer (EA). The source apportionment of PM 10 was further resolved by a receptor model based on chemical mass balance (CMB). Field measurement results showed that high concentrations of PM 10 (102 ± 25 μg/m 3 ) were commonly observed from late fall to early winter. The PM 10 concentration showed a consistently descending trend from the west coastline to the far east islands, with the highest PM 10 concentration at the coastal site (Site HQ) and the lowest at the far east island site (Site DY) in all seasons. Secondary inorganic aerosols (SIAs) and crustal materials were two most abundant compounds in PM 10 . Increasing anthropogenic trace elements was commonly observed in spring and winter, while northern monsoons were blown. High OC/EC ratios showed that secondary organic aerosols (SOAs) could be formed in the atmosphere of Minjiang estuary. Results from CMB receptor modeling indicated that the major sources of atmospheric PM 10 at the coastal and offshore island regions of the Minjiang estuary were soil dusts (13-33%), secondary aerosols (15-30%), transport emissions (11-17%), sea salts (8-27%), and agricultural debris burning (2-8%). Particularly, during the poor air quality periods, a rising contribution of industrial emissions (1-16%) was resolved, suggesting that atmospheric PM 10 over the Minjiang estuary was mainly attributed to cross-boundary transport rather than local emissions.

Chemical characteristics, source apportionment, and regional transport of marine fine particles toward offshore islands near the coastline of northwestern Taiwan Strait

“…Previous atmospheric PM 10 concentration measured at the Matsu Islands showed that PM 10 concentration in summer was always the lowest in the whole year, while high PM 10 concentrations were generally observed during the periods from late fall to early spring of the sequential year (Liao et al 2018 ). The temporal variation of PM 10 concentration correlated with wind direction in the marine boundary layer which was closely related with poor ambient air quality (Pollutants Standard Index, PSI > 100) during the prevalence of northeastern monsoons commonly occurs in the seasons of winter and spring.…”

“…Major stationary sources at the Matsu Islands include a 14.2-MW diesel-fired utility power plant, two breweries, and a few gas stations. However, high PM 10 concentration up to 129 μg/m 3 has been recorded by Taiwan EPA’s ambient air quality monitoring station located at the Nankang Island in the spring of 2011 (Liao et al 2018 ).…”