On-Road Measurement of Gas and Particle Phase Pollutant Emission Factors for Individual Heavy-Duty Diesel Trucks

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• 作者：Timothy R. Dallmann ; Steven J. DeMartini ; Thomas W. Kirchstetter ; Scott C. Herndon ; Timothy B. Onasch ; Ezra C. Wood ; Robert A. Harley
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：August 7, 2012
• 年：2012
• 卷：46
• 期：15
• 页码：8511-8518
• 全文大小：385K
• 年卷期：v.46,no.15(August 7, 2012)
• ISSN：1520-5851

文摘

Pollutant concentrations in the exhaust plumes of individual diesel trucks were measured at high time resolution in a highway tunnel in Oakland, CA, during July 2010. Emission factors for individual trucks were calculated using a carbon balance method, in which pollutants measured in each exhaust plume were normalized to measured concentrations of carbon dioxide. Pollutants considered here include nitric oxide, nitrogen dioxide (NO₂), carbon monoxide, formaldehyde, ethene, and black carbon (BC), as well as optical properties of emitted particles. Fleet-average emission factors for oxides of nitrogen (NO_x) and BC respectively decreased 30 卤 6 and 37 卤 10% relative to levels measured at the same location in 2006, whereas a 34 卤 18% increase in the average NO₂ emission factor was observed. Emissions distributions for all species were skewed with a small fraction of trucks contributing disproportionately to total emissions. For example, the dirtiest 10% of trucks emitted half of total NO₂ and BC emissions. Emission rates for NO₂ were found to be anticorrelated with all other species considered here, likely due to the use of catalyzed diesel particle filters to help control exhaust emissions. Absorption and scattering cross-section emission factors were used to calculate the aerosol single scattering albedo (SSA, at 532 nm) for individual truck exhaust plumes, which averaged 0.14 卤 0.03.