A study on effects of sea-land breeze on spatial and temporal distribution of particulate matter-A PM sampling protocol conducted at offshore and inland sites of South Taiwan

摘要

This study investigated the effects of sea-land breeze on the spatial distribution and temporal variation of particulate matter (PM) in the atmosphere around the coastal region of South Taiwan. Paniculate matter was simultaneously sampled both inland and offshore during two intensive sampling periods. The intensive PM sampling protocol was consecutively conducted for forty-eight hours. During the sampling periods, PM10 was simultaneously measured by either dicholomous samplers at four sites (two inland and two offshore sites) or β-ray monitors at ten sites of Taiwan Ambient Air Quality Sampling Network (TAAQSN). Particulate matter sampling on a boat navigated along the coastline of South Taiwan was further conducted to sample oceanic PM by a dichotomous sampler. Data obtained from both inland (twelve sites) and offshore (two sites) sampling was applied to plot the PM concentration contour with a software SURFER. Spatial distribution of PM10 concentration was further used to investigate the influences of sea-land breeze on the transport of PM around the coastal region of South Taiwan. Results showed that PM10 was transported back and forth across the coastline of investigation region. Particularly, high PM10 concentration was observed at the in-land sites in the daytime due to sea breeze, while high PM10 concentration was detected over the sea in the nighttime due to land breeze. This study revealed that the accumulation of particulate matter in the near-ocean region due to sea-land breeze influenced the spatial and temporal distribution of PM in the coastal region of South Taiwan.