Research of relationship between PM2.5 Air Quality and Meteorological Variables in Hsinchu Region
|關鍵字:||新竹地區;逆軌跡分析;多變數線性迴歸分析;空氣品質;氣象因子;PM2.5;Hsin-Chu Area;Back-trjectory analysis;Multiple linear regression;Air quality;Meteorological variables;PM2.5|
由2015 新竹縣/市三站PM2.5 事件日前三名之逆軌跡推估分析結果，由於前三名均發生於冬季，故可能是冬季逆溫層較厚，大氣擴散條件較原本就較差，再加上特殊事件引起PM2.5再升高。所以PM2.5事件日之主要原因可分為兩方面：第一係為中國大陸吹來之沙塵引起，因冬季主要風向為東北風，與本逆軌跡分析之氣流方向相符，且全島均受到影響，幾乎所有測站PM2.5均為事件日。第二為鄰近縣/市污染物境內傳輸所致，氣流由雲嘉南空品區往中部空品區，再經苗栗往新竹縣/市方向吹，造成PM2.5事件日的發生。故在空氣污染物防制上，建議新竹縣/市可與鄰近縣市聯手，共同研討防制策略。|
This study used the 2006 to 2015 data of air quality monitoring stations from Environmental Protection Administration of Executive Yuan. The air pollutants: PM2.5, PM10, CO, NO, NO2, NOX, O3, SO2, and meteorological data: temperature, rainfall, wind direction, wind speed, relative humidity. All data are presented by hourly. Three air quality monitoring stations are all selected in the region of Hsinchu County: Hsinchu station, Hukou station, Zhudong station. And use the method of multiple linear regression approach to do statistical analysis. At the same time, according to the PM2.5 event day of 2015 in Hsinchu County, the possible sources of pollutants were calculated by the back trajectory analysis model provided by the National Oceanic and Atmospheric Administration(NOAA). The results show that all of the pollutants, except O3, are gradually declining year by year, PM2.5 exceeded standard days are also gradually reduced. Indicating that the air quality in the Hsinchu County is improving year by year by the joint efforts of the Government and the people. In the monthly distribution, all of the air pollutants, except O3, are generally V-shaped, bottom appears in the summer to autumn. The reason is that the inversion layer is thicker in winter and the air convection is poorer, which leads to higher air pollutant concentration. PM2.5 and meteorological factors correlation coefficient analysis in Hsinchu County shows that PM2.5 has a negative low to medium correlation with air temperature, rainfall, relative humidity, wind direction and wind speed. According to the results of multiple linear regression analysis, the PM2.5 was negative low correlation with the meteorological factors except the wind direction, which was comparable with the correlation coefficient analysis. In R2 value, the minimum value is 0.17, the maximum value is 0.38, showed a low correlation. It may because of the PM2.5 related factors may need to include air pollution sources, such as the number of vehicles, types, number of factories, types, etc., or pollution condition in neighboring counties, or foreign pollutants. According to the results of back trajectory analysis result in Hsinchu County, the results show that the top three of 2015 PM2.5 event day were all occurred in the winter, probably because of the thicker inversion layer in winter and the worse atmospheric diffusion conditions. Furthermore, a special event triggered PM2.5 increased. Therefore, the main reasons for PM2.5 event day can be separate into two aspects: 1. Dust blowing from mainland China, mostly in the winter, the main wind direction is northeasterly, the same as back trajectory analysis of the airflow direction , and the whole island are affected, almost all of the air monitoring stations are PM2.5 event day. 2. The transmission of pollutants in the neighboring counties. The airflow is from southern Taiwan to central Taiwan, and then flows to the Hsinchu County through Miaoli. And then PM2.5 event day occurs. Therefore, in the air pollution control, the Hsinchu County should co-work with the neighboring counties to discuss prevention strategies.
|Appears in Collections:||Thesis|