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Characterization of PM-PEMS for in-use measurements conducted during validation testing for the PM-PEMS measurement allowance program
Abstract This study provides an evaluation of the latest Particulate Matter-Portable Emissions Measurement Systems (PM-PEMS) under different environmental and in-use conditions. It characterizes four PM measurement systems based on different measurement principles. At least three different units were tested for each PM-PEMS to account for variability. These PM-PEMS were compared with a UC Riverside's mobile reference laboratory (MEL). PM measurements were made from a class 8 truck with a 2008 Cummins diesel engine with a diesel particulate filter (DPF). A bypass around the DPF was installed in the exhaust to achieve a brake specific PM (bsPM) emissions level of 25 mg hp−1h−1. PM was dominated by elemental carbon (EC) during non-regeneration conditions and by hydrated sulfate (H2SO4.6H2O) during regeneration. The photo-acoustic PM-PEMS performed best, with a linear regression slope of 0.90 and R 2 of 0.88 during non-regenerative conditions. With the addition of a filter, the photo-acoustic PM-PEMS slightly over reported than the total PM mass (slope = 1.10, R 2 = 0.87). Under these same non-regeneration conditions, a PM-PEMS equipped with a quartz crystal microbalance (QCM) technology performed the poorest, and had a slope of 0.22 and R 2 of 0.13. Re-tests performed on upgraded QCM PM-PEMS showed a better slope (0.66), and a higher R 2 of 0.25. In the case of DPF regeneration, all PM-PEMS performed poorly, with the best having a slope of 0.20 and R 2 of 0.78. Particle size distributions (PSD) showed nucleation during regeneration, with a shift of particle size to smaller diameters (∼64 nm to ∼13 nm) with elevated number concentrations when compared to non-regeneration conditions.
Highlights ► Latest PM-PEMS were evaluated for in-use driving conditions. ► All PM-PEMS showed a negative biased measurement relative to the reference method. ► Photo-acoustic PM-PEMS performed best for non-regeneration conditions. ► None of the PM-PEMS performed well for regeneration conditions. ► Good consistency was observed between different units of same PM-PEMS.
Characterization of PM-PEMS for in-use measurements conducted during validation testing for the PM-PEMS measurement allowance program
Abstract This study provides an evaluation of the latest Particulate Matter-Portable Emissions Measurement Systems (PM-PEMS) under different environmental and in-use conditions. It characterizes four PM measurement systems based on different measurement principles. At least three different units were tested for each PM-PEMS to account for variability. These PM-PEMS were compared with a UC Riverside's mobile reference laboratory (MEL). PM measurements were made from a class 8 truck with a 2008 Cummins diesel engine with a diesel particulate filter (DPF). A bypass around the DPF was installed in the exhaust to achieve a brake specific PM (bsPM) emissions level of 25 mg hp−1h−1. PM was dominated by elemental carbon (EC) during non-regeneration conditions and by hydrated sulfate (H2SO4.6H2O) during regeneration. The photo-acoustic PM-PEMS performed best, with a linear regression slope of 0.90 and R 2 of 0.88 during non-regenerative conditions. With the addition of a filter, the photo-acoustic PM-PEMS slightly over reported than the total PM mass (slope = 1.10, R 2 = 0.87). Under these same non-regeneration conditions, a PM-PEMS equipped with a quartz crystal microbalance (QCM) technology performed the poorest, and had a slope of 0.22 and R 2 of 0.13. Re-tests performed on upgraded QCM PM-PEMS showed a better slope (0.66), and a higher R 2 of 0.25. In the case of DPF regeneration, all PM-PEMS performed poorly, with the best having a slope of 0.20 and R 2 of 0.78. Particle size distributions (PSD) showed nucleation during regeneration, with a shift of particle size to smaller diameters (∼64 nm to ∼13 nm) with elevated number concentrations when compared to non-regeneration conditions.
Highlights ► Latest PM-PEMS were evaluated for in-use driving conditions. ► All PM-PEMS showed a negative biased measurement relative to the reference method. ► Photo-acoustic PM-PEMS performed best for non-regeneration conditions. ► None of the PM-PEMS performed well for regeneration conditions. ► Good consistency was observed between different units of same PM-PEMS.
Characterization of PM-PEMS for in-use measurements conducted during validation testing for the PM-PEMS measurement allowance program
Khan, M. Yusuf (author) / Johnson, Kent C. (author) / Durbin, Thomas D. (author) / Jung, Heejung (author) / Cocker, David R. III (author) / Bishnu, Dipak (author) / Giannelli, Robert (author)
Atmospheric Environment ; 55 ; 311-318
2012-03-02
8 pages
Article (Journal)
Electronic Resource
English
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