Measurements of Particle Number and Mass Concentrations and Size Distributions in a Tunnel Environment

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• 作者：Michael D. Geller ; Satya Brata Sardar ; Harish Phuleria ; Philip M. Fine ; and Constantinos Sioutas
• 刊名：Environmental Science & Technology
• 出版年：2005
• 出版时间：November 15, 2005
• 年：2005
• 卷：39
• 期：22
• 页码：8653 - 8663
• 全文大小：276K
• 年卷期：v.39,no.22(November 15, 2005)
• ISSN：1520-5851

文摘

Particulate matter emissions were measured in two boresof the Caldecott Tunnel in Northern California duringAugust and September 2004. One bore (Bore 1) is open toboth heavy- and light-duty vehicles while heavy-dutyvehicles are prohibited from entering the second bore(Bore 2). Particulate matter number and mass size distributions,chemical composition, and gaseous copollutants wererecorded for four consecutive days near the entrance andexit of each bore. Size-resolved emission factors weredetermined for particle number, particle mass, elementalcarbon, organic carbon (OC), sulfate, nitrate, and selectedelements. The size distributions in both the bores showeda single large mode at roughly 15-20 nm in mobility diameter,with occasional smaller modes around 100 nm. The PM₁₀mass emission factor for heavy-duty vehicles was 14.5 timeshigher than that of light-duty vehicles. The particlesderived from diesel are more abundant in elemental carbon,70.9% of PM₁₀ emissions, as compared to the light-dutyvehicles. Conversely, a greater percentage of OC was foundin light-duty emissions than heavy-duty emissions. Incomparison to previous studies at the Caldecott Tunnel,less particle mass but more particle numbers are emittedby vehicles than was the case 7 years ago.