雖然我國環保署訂有PM10空氣品質標準來管制空氣中懸浮微粒(氣膠)，但是細氣膠和機動車輛排放以及光化學反應較為有關卻仍然沒有標準加以管制，針對我國訂定新的細氣膠空氣品質標準，是訂定PM2.5或是PM1標準較為適當？值得深入探討。 本文利用北部氣膠超級測站連續監測氣膠特性以及鄰近的新莊空氣品質監測站數據，分析2002年3月~2005年12月台北都會區PM1和PM2.5的物理、化學及光學特性。並於2005年8月、9月底到10月初以及12月進行平常日氣膠採樣。細氣膠觀測的結果顯示，氣膠中水溶性離子SO42-、NH4+、K+大多存在於小於1 μm以下，且由氯離子損失法計算，可以得知PM2.5氣膠含有較多的海鹽成分；以絕對主成分分析PM1和PM2.5主要的污染來源都是以交通和光化反應為主。在碳成分方面，除了裂解碳(OP)和扣除裂解碳的低溫元素碳(EC1-OP)以PM2.5-1含量較多外，其餘碳成分物種以PM1為主。在高污染事件下進行氣膠監測特性探討，發現不論是細氣膠高污染事件日、大陸沙塵前緣細氣膠高濃度事件或大陸沙塵過後高壓迴流，主要的氣膠污染物都存在於小於1 μm，顯示以PM1氣膠做為監測指標物，將較能瞭解受高污染事件影響的程度。此外，本文也發現PM1較PM2.5更能夠解釋環境中氣膠的光學效應。事實上，在許多時候當PM2.5濃度未達美國65 μg m-3標準時已經有相當濃度的PM1氣膠，這很容易使人們忽略此時氣膠對人體和環境的衝擊。 Although PM10 air quality standard has been set up for regulating ambient aerosols by Environmental Protection Administration (EPA) in Taiwan, fine aerosol which is more related to motor vehicle emissions and photochemical reactions is not yet regulated. It is worthwhile to investigate whether the new fine aerosol standard should be either PM2.5 or PM1 in Taiwan? This study assesses aerosol continuous monitoring characteristics from North Aerosol Supersite and the air quality data from nearby Hsin-Chuang monitoring site to analyze PM1 and PM2.5 physical, chemical, and optical properties from March 2002 to December 2005. In addition, filter-based aerosols waere collected in various days in August, September, October, and December 2005. The analysis of aerosol properties shows that major water-soluble ions like SO42-, NH4+, K+ are predominantly distributed in aerosol sizes below 1 μm. In contrast, more sea salts are found in PM2.5 from the calculation of chlorine loss. However, major sources for PM1 and PM2.5 are both from traffic activity and photochemical reactions. In aerosol carbon fractions, PM1 is predominant except for pyrolyzed carbon (OP) and low temperature evolved elemental carbon with the substraction of OP (EC1-OP) are dominated by PM2.5-1. The aerosol monitoring characteristics shows that major aerosol species are in submicron particles for high concentration events, high fine aerosol events in front of transported Yellow dusts, and high aerosol events under anticyclonic outflow after the passage of Yellow dust. This indicates PM1 is useful as a tracer in representing high aerosol events. Moreover, PM1 is better than PM2.5 in accounting for aerosol optical effects for the environment. In fact, submicron aerosols frequently reach a substantial concentration even without shooting up the US 65 μg m-3 standard. This might mislead people to underscore aerosol effects on human health and the environment.
