In-Use Emissions from Heavy-Duty Diesel Vehicles

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• 作者：Janet Yanowitz ; Robert L. McCormick ; and Michael S. Graboski
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：March 1, 2000
• 年：2000
• 卷：34
• 期：5
• 页码：729 - 740
• 全文大小：133K
• 年卷期：v.34,no.5(March 1, 2000)
• ISSN：1520-5851

文摘

This paper reviews in-use emissions from over-the-roadheavy-duty (greater than 8500 lb gross vehicle weight) dieselvehicles. Emissions of particulate matter (PM), oxides ofnitrogen (NO_x), carbon monoxide (CO), and hydrocarbon (HC)are considered. Emissions measurements have beenmade by chassis dynamometer, by remote sensing, and intunnel studies. There is reasonable agreement betweenthe different types of studies for emissions of NO_x,but agreement for emissions of other pollutants is qualitative.Remote sensing studies indicate that emissions of NOare normally distributed, while emissions of CO and HCare skewed to a few high emitting vehicles. Chassisdynamometer results indicate that average emissions ofPM, CO, and HC have been reduced during the past twodecades, but average emissions of NO_x have not changed.Thus, emissions regulations for PM have been somewhateffective, although the degree of PM reduction is lessthan expected based on changes in the standards. Emissionregulations have apparently not been effective at reducingin-use NO_x. Chassis dynamometer emissions of PM arewidely variable, typically spanning an order of magnitudefor any given model year. This variability is attributed tovariation in testing altitude and temperature, inertial weight,test cycle, vehicle condition (deterioration), and drivervariability. The fleet of vehicles tested by chassis dynamometerhas been compared to the in-use fleet and found tooveremphasize transit buses (over one-third of the testedfleet). In comparison, there are estimates that transitbuses generate less than 5% of the vehicle miles traveledfor heavy-duty vehicles. The tested fleet was also foundto be newer and of lower mileage than the in-use fleet.Several improvements to study methodology and newresearch directions are proposed.