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The SURFER model is seldom used in combination with the CMB model to look for PM 10 hot spots and estimate the contribution of various sources, and this is the aim of the current study. In addition, the hot spots of ambient particulate matter (PM) and their physicochemical characteristics in a highly polluted zone in southern Taiwan were further investigated and compared. The experimental results show that PM 10 concentration in the fall was higher than in spring and summer. Moreover, northern monsoons transported suspended particles from the upwind emission sources to the sampling sites, causing an increase in secondary aerosols such as sulfate and nitrate. The contribution of secondary aerosols in rural areas such as Dai-liao and Chao-zhou (32.1% and 29.9%) and suburban areas like Ren-wu and Lin-yuan (28.7% and 29.0%) were higher than those in urban areas such as Hsiao-kang (20.3%). The higher Fe concentration in Hsiao-kang was attributed to PM emission from steel factories (6.9-7.8%). In this study, the organic carbon/elemental carbon (OC/EC) in PM 2.5 and PM 10 for the five sites were all in the order of Hsiao-kang > Ren-wu > Lin-yuan > Chao-zhou > Da-liao. In fall, farm burns are very common in both Dai-liao and Chao-zhou, and this source contributed approximately 7.3% and 6.3%, respectively, to these results. The seasonal variation of the contribution from vehicle exhausts to PM 10 (13.9-27.5%) at Hsiao-kang was always higher than those at other sites, especially in the fall. The results could provide important information for cost-effective control strategies to improve ambient air quality in hot spot areas.

This study investigates the effects of sea-land breezes (SLBs) and northeastern monsoon (NEM) on the physicochemical properties of particulate matter (PM) in the atmosphere over southeastern coastal region of Taiwan Strait. The intensive PM sampling protocol was consecutively conducted for forty-eight hours. During the sampling periods, PM 2.5 and PM 2.5-10 were simultaneously measured with dichotomous samplers at four sites (two inland and two at offshore sites) and PM 10 was measured with beta-ray monitors at these same four sites. Strong SLBs were regularly observed in the coastal region of southern Taiwan during the SLBs periods, while significant northeastern monsoons appeared during the NEM periods. The mass ratios of PM 2.5 /PM 10 during the NEM periods were always higher than the SLBs periods. The most abundant ionic species of PM were SO 4 2-, NO 3 -, and NH 4 + . The most common chemical compounds of PM in southern Taiwan were ammonium sulfate ((NH 4 ) 2 SO 4 ) and ammonium nitrate (NH 4 NO 3 ). Carbon contents of PM during the NEM periods were higher than during the SLBs periods. The organic-to-elemental-carbon ratio (OC/EC) of PM 2.5 ranged from 1.05 to 4.39 with an average of 2.26. The order of major metallic elements of PM 2.5 in the SLBs and NEM periods is Fe > Ca > K > Al > Mg > Zn > Pb and Ca > Fe > Al > K > Mg > V > Ni, respectively, and of PM 2.5-10 is Ca > K > Al > Fe > Mg > Zn and Fe > Ca > Al > K > Mg > V > Ni, respectively. This study reveals that the accumulation of PM offshore, due to land breezes, influences the tempospatial distribution of PM at the coastal region in southern Taiwan. Moreover, the nss- [

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The influence of sea-land breezes (SLBs) on the spatial distribution and temporal variation of particulate matter (PM) in the atmosphere was investigated over coastal Taiwan. PM was simultaneously sampled at inland and offshore locations during three intensive sampling periods. The intensive PM sampling protocol was continuously conducted over a 48-hr period. During this time, PM 2.5 and PM 2.5-10 (PM with aerodynamic diameters Յ2.5 m and between 2.5 and 10 m, respectively) were simultaneously measured with dichotomous samplers at four sites (two inland and two offshore sites) and PM 10 (PM with aerodynamic diameters Յ10 m) was measured with ␤-ray monitors at these same 4 sites and at 10 sites of the Taiwan Air Quality Monitoring Network. PM sampling on a mobile air quality monitoring boat was further conducted along the coastline to collect offshore PM using a ␤-ray monitor and a dichotomous sampler. Data obtained from the inland sites (n ϭ 12) and offshore sites (n ϭ 2) were applied to plot the PM 10 concentration contour using Surfer software. This study also used a three-dimensional meteorological model (Pennsylvania State University/National Center for Atmospheric Research Meteorological Model 5) and the Comprehensive Air Quality Model with Extensions to simulate surface wind fields and spatial distribution of PM 10 over the coastal region during the intensive sampling periods. Spatial distribution of PM 10 concentration was further used in investigating the influence of SLBs on the transport of PM 10 over the coastal region. Field measurement and model simulation results showed that PM 10 was transported back and forth across the coastline. In particular, a high PM 10 concentration was observed at the inland sites during the day because of sea breezes, whereas a high PM 10 concentration was detected offshore at night because of land breezes. This study revealed that the accumulation of PM in the near-ocean region because of SLBs influenced the tempospatial distribution of PM 10 over the coastal region.