為瞭解交通源路旁大氣細微粒(PM2.5)組成特性,本研究於2014年2月21日至3月1日在屏東市水利署七河川局旁(高屏交通主幹道,下以七河局表示)及里港鄉里港教會旁(砂石車主要幹道,下以里港教會表示)地面以PQ200及Dichot進行連續9天日夜大氣微粒密集採樣,以探討兩交通源路旁大氣粗細微粒濃度、PM2.5上水溶性離子、碳成分及金屬組成特性。初步研究結果顯示:無論上班日或假日,七河局及里港教會兩測點大氣PM2.5濃度日間大致上均較夜間值低,而PM2.5-10濃度日間則大致上均較其夜間值高。無論日間或夜間,七河局大氣PM2.5及PM2.5-10平均濃度上班日均分別較假日之值高;里港教會日間時其大氣PM2.5及PM2.5-10之平均濃度上班日與假日均幾乎相近,而在夜間上班日時其大氣PM2.5及PM2.5-10平均濃度則均較假日時之值高。兩測點大氣PM2.5質量中有83%以上是由水溶性離子(佔40%以上)及碳成分含(EC與OC,佔35%)及金屬(佔8%)所組成。PM2.5上所測水溶性離子中含量最多之三種離子為SO42-、NO3-及NH4+,兩測點日間大氣PM2.5上SO42-含量明顯較夜間值高;反之,PM2.5上NO3-則夜間較日間高;ΣIons中此三種離子濃度和佔之百分比平均在90%以上;兩測點大氣PM2.5上OC/EC之平均值分別為1.57及1.91,兩採樣點PM2.5上主要金屬為 Mg、Al、Ca及Fe等,其餘11種來自人為活動排放之金屬均以Mn、Ni、Zn及Pb等四金屬為主;且Mn、Zn及Pb等金屬與柴油車之排氣有關。
To understand the composition characteristics (concentrations, water soluble ions, carbon species, and metals) of atmospheric fine particles (PM2.5) near traffic sources, PQ200 and Dichot were used for daytime and nighttime intensive sampling at the Seventh River Management Office, Water Resources Agency, Ministry of Economic Affairs (located near a main road connecting Kaohsiung and Pintung, denoted as SRMO) and Ligang Church (the main road for gravel trucks) from February 21 to March 1, 2014. Preliminary results showed that on both weekdays and weekends, most of daytime PM2.5 concentrations were lower than those of nighttime PM2.5 at both SRMO and Ligang, while a reverse trend was observed for PM2.5-10. Both daytime and nighttime measurements showed that the average PM2.5 and PM2.5-10 concentrations on weekdays were higher than those on weekends at SRMO. At Ligang Church, daytime average PM2.5 and PM2.5-10 concentrations on weekdays were similar to those on weekends, while nighttime PM2.5 and PM2.5-10 concentrations on weekdays were higher than those on weekends. At both sampling sites, more than 83% of atmospheric PM2.5 consisted of water-soluble ions (>40%), carbon species (EC and OC, 35%), and metals (8%). The most abundant species of water-soluble ions in PM2.5 were SO42-, NO3-, and NH4+. The daytime SO42- concentrations in PM2.5 were significantly higher than nighttime ones at both sites. However, the concentrations of nighttime NO3- in PM2.5 were higher than those of daytime. The sum of SO42-, NO3-, and NH4+ accounted for more than 90% of ΣIons. The average OC/EC values in PM2.5 were 1.57 and 1.91 at SRMO and Ligang, respectively. The main metals in PM2.5 at both sites were Mg, Al, Ca, and Fe. Mn, Ni, Zn, and Pb were the major species of the investigated 11 metals from anthropogenic activities; among these metals, Mo, Zn, and Pb were related to the emission from diesel vehicles.