Evaluation of the Dekati Mass Monitor for the Measurement of Exhaust Particle Mass Emissions
详细信息 查看全文
- 作者：Athanasios Mamakos ; Leonidas Ntziachristos ; Zissis Samaras
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：August 1, 2006
- 年：2006
- 卷：40
- 期：15
- 页码：4739 - 4745
- 全文大小：409K
- 年卷期：v.40,no.15(August 1, 2006)
- ISSN：1520-5851
文摘
The Dekati mass monitor (DMM) is an instrument whichmeasures the mass concentration of airborne particles inreal time by combining aerodynamic and mobility sizeparticle classification. In this study, we evaluate theperformance of the DMM by sampling exhaust from fiveengines and vehicles of different technologies in both steady-state and transient tests. DMM results are found higherthan the filter-based particulate matter (PM) by 39 ± 24%(range stands for ± one standard deviation) for 62diesel tests conducted in total and 3% and 14% higher,respectively, in two gasoline tests. To explore whether thedifference occurs because of the different measurementprinciples of DMM and filter-based PM, the DMM operationis replicated over steady-state tests by combining anelectrical low-pressure impactor (ELPI) and a scanningmobility particle sizer (SMPS). The correlation of ELPI andSMPS derived mass and filter-based PM is satisfactory(R2 = 0.95) with a mean deviation of 5 ± 15%. For the sametests, the correlation of DMM with PM was also high(R2 = 0.95), but DMM exceeded PM by 44 ± 23% on average.The comparison of ELPI and SMPS and DMM resultsreveals that the latter overestimates both the geometricmean diameter and especially the width of the particle mass-weighted size distribution. These findings demonstratethat the statistically significant difference between the DMMand the filter-based PM cannot just originate from thedifferent measurement principles but also from the actualimplementation of the combined aerodynamic-mobilitymeasurement in the DMM. Optimizing the DMM will requirechanges in its design and/or the calculation algorithm toimprove the resolution and width of the aerodynamic sizedistribution recorded.