嘉義縣空氣盒子與環保署空氣監測站PM2.5濃度差異之影響分析

Comparing PM2.5 Concentrations Measured by AirBox and Environmental Protection Administration’s Air Quality Monitoring Network in Chiayi County

目的：分析空氣盒子(AirBox)與環保署測站(EPA-TAQMN)監測系統細懸浮微粒(PM2.5)濃度測值之差異。方法：本研究以嘉義縣作為研究地區，蒐集2016-2018年EPA-TAQMN朴子測站及新港測站與鄰近AirBox之PM2.5濃度及氣象因子(溫度、相對濕度、累積降雨量、風速及風向)資料。各變數以ADF檢定(Augmented Dicey-Fuller test)進行定態性的檢定，檢驗資料是否具時間趨勢。以描述性統計(平均值、標準差與百分比)、推論統計(獨立樣本t檢定、單因子變異數分析與斯皮爾曼等級相關)進行分析。結果：AirBox測得PM2.5平均濃度(47.48μg/m3)顯著高於EPA-TAQMN(25.81μg/m3)(p<0.001)；兩者間具有顯著正相關(r=0.844)。東北季風期間，PM2.5濃度與累積降雨量(r=-0.616)、風速(r=-0.307)呈顯著負相關；非東北季風期間，PM2.5濃度則與溫度(r=-0.650)、相對濕度(r=-0.205)、風速(r=-0.504)呈顯著負相關。AirBox與EPA-TAQMN之距離相近，PM2.5濃度差異小(p<0.001)。結論：AirBox對大氣PM2.5監測數據高於EPA-TAQMN，與EPA-TAQMN存在高度相關性，結果仍具參考價值。可提供社區民眾戶外活動與監測地方性污染源之參考依據。

Objectives. This study compared fine particulate matter (PM2.5) concentration data measured by AirBox devices and the Environmental Protection Administration of Taiwan’s Air Quality Monitoring Network (EPA-TAQMN).
Methods. PM2.5 concentrations were obtained from the EPA-TAQMN (Puzi and Xingang stations) and AirBox devices during the study period, 2016-2018. Meteorological data (e. g., temperature, relative humidity, rainfall, wind speed, and wind direction) were obtained from the EPA-TAQMN. The augmented Dickey-Fuller (ADF) test was used to analyze the stationary time series. Descriptive statistics (mean, standard deviation, and percentage) and inferential statistics (independent t test, one-way ANOVA, and Spearman's rank correlation coefficient) were employed to analyze the data.
Results. The average PM2.5 concentrations obtained by AirBox (47.48μg/m3) were significantly higher than those reported by the EPA-TAQMN (25.81μg/m3; p<0.001). AirBox and EPA-TAQMN PM2.5 concentrations were significantly and positively correlated (r=0.844). During the northeast monsoon period, PM2.5 concentrations were significantly; negatively correlated with rainfall (r=-0.616) and wind speed (r=-0.307). During non-northeast monsoon periods, PM2.5 concentrations wew significantly; negatively correlated with temperature (r=-0.650), relative humidity (r=-0.205), and wind speed (r=-0.504). Shorter distances between the AirBox and the EPA-TAQMN stations were associated with smaller differences in PM2.5 concentrations (p<0.001).
Conclusion. PM2.5 concentrations reported by AirBox stations were higher than those reported by EPA-TAQMN stations; however, AirBox and EPA-TAQMN data were highly correlated. The PM2.5 concentrations obtained by AirBox can be used as a reference for those organizing outdoor activities for community residents and for monitoring local pollution levels.