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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.

This study investigated the ozone formation mechanism and air mass trajectory via simultaneous air quality sampling around the coastal region of urban Kaohsiung. Vertical concentration profiles of O 3 and its precursors (NO x and VOCs) were sampled and measured at inland and offshore sites during eight intensive sampling periods. The intensive sampling periods were divided into three categories based on meteorological condition: the sea-land breeze period, the northeastern monsoon period, and the mixed period. Vertical profile results showed that the stratification of O 3 was commonly observed at 40 out of 64 sampling sites accounting for 62.5% of the total O 3 measurement. The results obtained from VOCs measurement indicated that the major species of VOCs was acetone, which accounted for 16.25-64.05% of total TVOCs-C 2 in the offshore region, while the major species of VOCs in the inland region was toluene, which accounted for 6.41-43.77 % of total TVOCs-C 2 . Backward trajectories showed that air pollutants emitted from land sources could transport to the offshore region, resulting in a high concentration of oversea NO x and VOCs. Major species of VOCs with high O 3 formation potential were found to be aromatics in the low atmosphere around the coastal region of metro Kaohsiung.

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This study investigated the seasonal variation and spatial distribution of gaseous and particulate mercury at a unique mercury-contaminated remediation site located at the near-coastal region of Tainan City, Taiwan. Gaseous elemental mercury (GEM), particulate mercury (PTM), and dustfall mercury (DFM) were measured at six nearby sites from November 2009 to September 2010. A newly issued Method for Sampling and Analyzing Mercury in Air (National Institute of Environmental Analysis [NIEA] Method A304.10C) translated from U.S. Environmental Protection Agency (EPA) Method IO-5, was applied for the measurement of atmospheric mercury in this particular study. One-year field measurements showed that the seasonal averaged concentrations of GEM and PTM were in the range of 5.56-12.60 and 0.06-0.22 ng/m 3 , respectively, whereas the seasonal averaged deposition fluxes of DFM were in the range of 27.0-56.8 g/km 2 -month. The maximum concentrations of GEM and PTM were 38.95 and 0.58 ng/m 3 , respectively. The atmospheric mercury apportioned as 97.42-99.87% GEM and 0.13-2.58% PTM. As a whole, the concentrations of mercury species were higher in the springtime and summertime than those in the wintertime and fall. The southern winds generally brought higher mercury concentrations, whereas the northern winds brought relatively lower mercury concentrations, to the nearby fishing villages. This study revealed that the mercury-contaminated remediation site, an abandoned chlor-alkali manufacturing plant, was the major mercury emission source that caused severe atmospheric mercury contamination over the investigation region. The hot spot of mercury emissions was allocated at the southern tip of the abandoned chlor-alkali manufacturing plant. On-site continuous monitoring of GEM at the mercurycontaminated remediation site observed that GEM concentrations during the open excavation period were 2-3 times higher than those during the nonexcavation period.