探討都會區國小附近一氧化氮及臭氧濃度之影響因子：以台南地區為例

Abstract

隨著都市化程度的提高，空氣污染情形也日趨嚴重，許多流行病學研究指出在都會區鄰近街道國小的學童當中，普遍有著較高的慢性呼吸道疾病發生率，如何正確且快速地得到空氣污染物的濃度資料，有助於我們進行各種相關控制來降低空氣污染的情形。 本研究利用差分式紫外光光譜儀（UV-DOAS）分別在台南市南區、中西區和東區各選取一間國小進行一星期的空氣品質監測，並收集現場交通流量與氣象資料，進行一氧化氮和臭氧的定性與定量分析，分析空氣污染濃度變化趨勢，利用混合模型同時評估不同的交通因子以及氣象因子對空氣污染物濃度的影響，比較不同模型下模擬值與實際監測的相關性，並透過條件機率函數（CPF）釐清可能的污染貢獻來源。 研究結果顯示，南區國小交通流量為2127輛/小時，一氧化氮與臭氧逐時平均濃度分別6.17~56.1ppb和5.38~94.43ppb，中西區國小交通流量為2674輛/小時，一氧化氮與臭氧逐時平均濃度分別為2.75~37.58ppb和17.95~117.03ppb，東區國小交通流量為957輛/小時，一氧化氮與臭氧逐時平均濃度分別為3.09~62.46ppb和10.81~76.44ppb；利用混合模型發現空氣污染濃度主要受到氣象變項影響，交通變項影響則不顯著，利用條件機率函數探討各國小的可能主要污染來源，結果發現南區國小主要污染源可能為其西南方的安平工業區，中西區國小主要污染源來自其西南方的道路交通，東區國小則有低估其西南方道路交通流量所帶來影響的可能。

The air pollution has become more serious with the booming of urbanization. Many epidemiological studies showed higher occurrence of chronic respiratory diseases in elementary children living near major roads. Therefore, it is important to assess the concentrations and distributions of air pollutants accurately in a timely fashion in these areas and to identify the contributing factors. Measurements of nitric oxide and ozone in this study were facilitated by the use of ultraviolet differential optical absorption spectroscopy（UV-DOAS）. We selected one elementary school at the south, west central, and east area in Tainan city, respectively. Air quality data, real-time traffic counts, and meteorological information were collected simultaneously at each school for 7 days. The mixed models were used to estimate the effect of traffic and meteorological factors on pollutant concentrations. Additionally, we compared the correlation between the monitored and predicted levels of air pollutants. The conditional probability functions（CPFs） were used to clarify the possible contribution of pollution sources. Our results showed that the traffic density were 2127 counts/hour, 2674 counts/hour, and 957 counts/hour in south, west-central, and east area, respectively. The concentrations of nitric oxide and ozone were 6.17~56.1 ppb and 5.38~94.43 ppb, 2.75~37.58 ppb and 17.95~117.03 ppb, and 3.09~62.46 ppb and 10.81~76.44 ppb in south, west-central, and east area, respectively. The meteorological factors affected the concentration of air pollutants more significantly than traffic factors. The conditional probability functions（CPFs） showed that the main sources of air pollution in the south district school may come from Anping Industrial area located at its southwest direction. The west central district school may be affected by the traffic at its southwest side. For the east district school, the impact from the traffic emission might be underestimated.