Characterization of PM-PEMS for in-use measurements conducted during validation testing for the PM-PEMS measurement allowance program

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• 作者：M. Yusuf Khan^a ; Kent C. Johnson^a ; ^{kjohnson@cert.ucr.edu} ; Thomas D. Durbin^a ; Heejung Jung^a ; David R. Cocker III^a ; Dipak Bishnu^b ; Robert Giannelli^c
• 关键词：PM-PEMS ; Diesel particulate matter ; Quartz crystal microbalance ; Photo-acoustic ; Regneration ; Non-regeneration ; Size distribution
• 刊名：Atmospheric Environment
• 出版年：2012
• 期刊代码：11_13522310
• 类别：env
• 出版时间：August, 2012
• 卷：55
• 期：Complete
• 页码：311-318
• 文件大小：453 K

摘要

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聽mg聽hp^鈭?h^鈭?. 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 R² 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聽=聽1.10, R²聽=聽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 R² of 0.13. Re-tests performed on upgraded QCM PM-PEMS showed a better slope (0.66), and a higher R² of 0.25. In the case of DPF regeneration, all PM-PEMS performed poorly, with the best having a slope of 0.20 and R² of 0.78. Particle size distributions (PSD) showed nucleation during regeneration, with a shift of particle size to smaller diameters (鈭?4聽nm to 鈭?3聽nm) with elevated number concentrations when compared to non-regeneration conditions.