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Evaluating mobile monitoring of on-road emission factors by comparing concurrent PEMS measurements
Citation:
Wu, Y., H. Wang, K. Zhang, S. Zhang, R. Baldauf, P. Deshmukh, AND R. Snow. Evaluating mobile monitoring of on-road emission factors by comparing concurrent PEMS measurements. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 736:NA, (2020). https://doi.org/10.1016/j.scitotenv.2020.139507
Impact/Purpose:
Diesel truck emissions have been shown to have adverse human health and environmental effects. Characterizing emission rates from these vehicles is important to improve local, regional and global air quality. This paper describes and evaluates a method to quickly measure truck and car emission factors by chasing vehicles on the road. The results can greatly improve understanding of emission factors to improve air quality modeling. Chase methods can be used by regulatory agencies and academics to evaluate and improve the process of air quality assessment and the effectiveness of pollution control strategies
Description:
Many countries have adopted portable emissions measurement system (PEMS) testing in their latest regulations to measure real-world vehicular emissions. However, its fleetwide implementation is severely limited by the high equipment costs and lengthy setup procedures, posing a need to develop more cost-effective, efficient emission measurement methods, such as mobile chasing tests. We conducted conjoint PEMS-chasing experiments for twelve heavy-duty diesel vehicles (HDDTs) to evaluate the accuracy of mobile measurement results. Two data processing approaches were integrated to automate the calculations of fuel consumption-based emission factors of nitrogen oxides (NOX). With a total of 245 plume chasing tests conducted, and then averaged by vehicle and road types, we found that the relative errors of vehicle-specific emission factors using an algorithm developed for this project were within approximately ± 20% of the PEMS results for all tested vehicles. Stochastic simulations suggested reasonable results could be obtained using fewer chasing tests per vehicle (e.g., 71% for freeways and 93% for local road, equivalent to two chase tests per vehicle). This study improves the understanding of the accuracy of the mobile chasing method, and provides a practical approach for real-time emission measurements for future scaled-up mobile chasing studies
URLs/Downloads:
DOI: Evaluating mobile monitoring of on-road emission factors by comparing concurrent PEMS measurements