Air quality was influenced by many factors, in South Taiwan, air pollutants transportation caused by monsoon or sea-land breeze that may caused high air pollution events. Air pollutant generated by human activity on daytime, then transported and accumulated at sea region by land breeze during the nighttime. Unfortunately, air pollutants that accumulated over sea on night may transport back to land by sea breeze on daytime. Besides, monsoon may carry air pollutants from other regions to South Taiwan and caused high air quality event. Till now, air quality influenced by sea-land breeze and monsoon were not verified in South Taiwan. This study investigated the temporal variation and spatial distribution of air pollutants in the atmosphere around the coastal region of South Taiwan. Ambient air pollutants were simultaneously monitored both inland and offshore. Inland monitoring was conducted at two sites associated with fourteen national air quality monitoring stations, while offshore monitoring was conducted at two sites both in an island and on the boat. A protocol of ambient air quality monitoring was conducted for forty-eight hours. Gaseous air pollutants (i.e. CO, SO2, NOX, THC, and O3) were continuously monitored instrumentally. Data obtained from both inland and offshore monitoring were applied to plot the concentration contour by a software SURFER. Hourly variation of air pollutant concentrations was further used to study the influences of sea-land breezes on the transportation of air pollutants around the coastal region of South Taiwan for different seasons. In August and November, 2006 and May, 2007, sea-land breeze was observed during sampling period and sea breeze arise from 9:00 A.M. to 24:00 P.M. The average wind velocity was 1~4 m/s during the sampling period. In January and March, 2007, prevail wind direction was north direction and northeast direction (270o~30o), that was influenced by northeast monsoon during the sampling period. The average wind velocity was 2~4 m/s. The results showed that distribution of air pollutants, including O3, NOX, THC, and CO influenced by sea-land breezes, particularly for ozone. Air pollutants transported to sea region during the nighttime, and transported back at daytime. This phenomenon cause air pollutants accumulated between Kao-Ping and sea region. In general, NOX generated by transportation and industrial process, thus high concentration of NOX appeared during traffic congestion period and at industry region, mainly Kaohsiung city and Linyuang industrial region. However, sea-land breeze effect upon transportation of air pollutants wasn¡¦t obvious for SO2. High SO2 concentration appeared at Linyuang industrial region and Siaogang at daytime, and transported to region along the coast. During northeastern monsoon season, northeast winds obstructed by Central Mountain Range cause air pollutants accumulated at Kao-Ping region. High NOX concentration appeared at Kaohsiung City and Linyuang industrial region. SO2 accumulated at Siaogang and Linyuang during the nighttime might be caused by high atmospheric pressure system and blew air pollutants to Linbian. CO was accumulated at Siaogang at daytime and transported to Donggang, while THC was accumulated at Donggang whole day.

Kaohsiung region with high percentage (6-8%) of poor air quality (PSI>100) has been announced officially by Taiwan Environmental Protection Administration (TEPA) as the worst air quality region among seven Air Quality Zones (AQZ) in Taiwan. Air pollutant dispersion was influenced by many factors including meteorology and topography. Particulate matter (PM) transportation caused by northeastern monsoon and/or sea land breeze might resulted in air pollution episodes. In summer, PM might be transported back and forth across the coastline of Kaohsiung region by sea land breeze. Particularly, high PM10 concentration has been observed at the inland sites in the daytime due to sea breeze. In autumn and winter, PM could be transported northeasterly to the inland range and covered a huge area of entire region. The objective of this study was to investigate the accumulation of particulate matter in the near-ocean region due to northeastern monsoon and sea-land breeze, and the spatial and temporal distribution of PM in the coastal region of Southern Taiwan. This study investigated the effects of sea-land breeze and northeastern monsoon on the spatial distribution and temporal variation of particulate matter in the atmosphere around the coastal region of South Taiwan. Particulate matter was simultaneously sampled both inland and offshore during five intensive sampling periods on August 16-17, 2006, November 2-3, 2006, January 24-25, 2007, March 6-7, 2007 and May 2-3, 2007, respectively. Inland monitoring was conducted at two sampling sites associated with fourteen Taiwan ambient air quality monitoring stations, while offshore monitoring was conducted at the Hsiau-Liou-Chiou (HLC) island (approximately 14 km offshore) and on an air quality monitoring boat. In August and November, 2006 and May 2007, sea-land breeze was observed during sampling period and sea breeze arose from 9:00 A.M. to 24:00 P.M. The average wind velocity was 1~4 m/sec during the sampling period. In January and March, 2007, prevail wind direction was north and northeast (300 o ~30 o), that was influenced by northeastern monsoon. The average wind velocity was 2~4 m/sec during the sampling period. The backward trajectories of air parcel transported toward the inland ambient air quality sampling sites around the coastal region of South Taiwan were plotted during the sea land breeze and northeastern monsoon periods. The results showed that distribution of PM10 was significantly influenced by sea land breezes. During the sea-land breeze periods, sea breezes blown in the early morning would transport the offshore PM10 back to the inland sites in Kaohsiung metropolitan area resulting in high PM10 concentration in the afternoon. On the contrary, high PM10 concentration observed during the northeastern monsoon periods was mainly brought from northerly wind which transported PM10 originated from the northern region (i.e. Tainan and Yunlin Counties) to Kaohsiung metropolitan area. This study further compared the atmospheric aerosols sampled at Kaohsiung metropolitan area with the resuspended sands blown from top soils collected near the riversides. An enrichment factor (EF) was applied to correlate the downwind atmospheric aerosols at three TEPA sampling sites in Kaohsiung to top soil sources originated from Tachia river, Zhoushui river, Tesngwen river and Kaoping river, respectively. This study revealed that atmospheric aerosols sampled at Southern Taiwan can be correlated to top soil sources near the riversides. Further investigation of enrichment factors indicated that, among four rivers, Kaoping river had the highest correlation to PM10 sampled in Kaohsiung. The enrichment factors were in the order of Kaoping river (EF=0.8~1.9) > Tsengwen river (EF=0.8~2.6) > Zhuos river (EF=1.0~2.8) > Tachia river (EF=1.1~4.2). The results indicated that atmospheric aerosols (i.e. PM10) had relatively higher correlation with the nearest river, Kaoping river, than other three rivers.