摘要： Yunlin County is located in the central part of western Taiwan with major emissions from the Mailiao industrial park, the Taichung Power Plants and heavy traffic. In order to understand the influence of meteorological conditions on PM2.5 concentrations in Yunlin County, we applied a two-stage cluster analysis method using the daily averaged surface winds from four air quality monitoring stations in Yunlin County to classify the weather pattern. The study period includes 1095 days from Jan 2013 to December 2015. The classification results show that the low PM2.5 concentration occurs when the synoptic weather in Taiwan is affected by the strong southwesterly monsoonal flow. The high PM2.5 concentration occurs when Taiwan is under the influence of weak synoptic weather conditions and continental high-pressure peripheral circulation. A high PM2.5 event was studied and the Weather Research and Forecasting (WRF) meteorological model was performed. The result indicated that due to being blocked by the Central Mountain Range, Yunlin County, which is situated on the leeside of the mountains, exhibits low wind speed and strong subsidence behavior that favors PM2.5 accumulation. •Investigate influence of meteorological conditions on PM2.5 concentrations in Yunlin County.•Cluster analysis was performed using observed wind to classify weather pattern.•High PM2.5 is associated with weak synoptic and continental high-pressure peripheral circulation.•Low wind speed and strong subsidence favors PM2.5 accumulation in Yunlin County. 出版者： Elsevier Ltd 出版日期： 2016-11 出處： Atmospheric Environment, 2016-11, Vol.144, p.397-408 資源來源： Elsevier ScienceDirect Journals Complete 版權： 2016 Elsevier Ltd 識別號： ISSN: 1352-2310 識別號： EISSN: 1873-2844 識別號： DOI: 10.1016/j.atmosenv.2016.09.001
