10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Mobile Chasing Measurement of Black Carbon and Nitrogen Oxides Emissions from Heavy-duty Vehicles in China
SHAOJUN ZHANG, Hui Wang, Ye Wu, K. Max Zhang, Cornell University
Abstract Number: 1509 Working Group: Instrumentation
Abstract The measurement techniques of vehicle emissions have achieved substantial advances in recent years, which have spurred the progressive implementations of stringent emission regulations. Notably, portable emissions measurement systems (PEMSs) have played an essential role in regulating real-world vehicle emissions. However, although the PEMS testing method has the useful features, the expensive instrumental cost and long experimental duration may become limitations to measure emission factors of massive on-road vehicles. Thus, we see a need for cost-effective and fast-response vehicle emission measurement methods to be developed and improved. In this study, we integrated a mobile measurement platform by equipping one Mini Van with multiple high-accuracy analyzers for measuring instantaneous concentrations of CO2, CO, NO/NOX, particle number, and black carbon (BC). For example, one EcoPhysics Analysator (Model CLD66) was applied to record continuous NOX concentration profiles on the road, while one Aethalometer (Model AE-33) was used to measure real-time BC concentration. According to the concentration elevation ratios of targeted pollutants to CO2 compared with road environmental baselines, fuel consumption-based emission factors of individual trucks are estimated. Comparative studies were conducted between PEMS and mobile chasing for BC and NOX emission factors of typical diesel trucks, which provided sufficient evidences for the effective measurement of real-world emission factors using the mobile platform.
This mobile platform was further applied to measure emission factors of on-road diesel trucks on highways. During 2017 and 2018, we launched a large-scale field study in several provincial regions of China (e.g., Beijing, Tianjin, Hebei, Henan and Sichuan), in which nearly one thousand trucks were measured by chasing on typical highways. Our preliminary results show the China IV diesel trucks could effectively reduce BC emissions than the older China III trucks. Nature gas-powered trucks and buses emit significantly lower BC than the diesel engines by at least one order of magnitude. However, relative to China III diesel vehicles, we could find no significant improvements in NOX emission factors for either China IV diesel trucks using selective catalytic reduction or nature gas fueled vehicles. These findings have highlighted great challenges to control NOX emissions from modern heavy-duty fleets in China and will be useful to update road emission inventories.