Suitability of Epiphaniometer Measurements for On-Road Experiments and Intercomparison with the Diffusion Charging Sensor

摘要

During the Coordinating Research Council (CRC) E-43 project 'Diesel Aerosol Sampling Methodology' an epiphaniometer (EPI) was one of two instruments in use to measure surface properties of the sampled aerosol. This report describes the general instrument handling and the subsequent data analysis pr ocedure, followed by the discussion of selected EPI data collected during the project. Data intercomparison is shown for EPI and diffusion charging sensor (DC) results. Further details on the surface area measurements during the E-43 project, also involving scanning mobility particle sizer (SMPS) measurements, are discussed in Bukowiecki et al. (2002). The selected examples (EPI measurements during an October 1999 truck chase experiment, during the wind tunnel study at Langley, VA in 1999 and during chassis dynamometer experiments in Spring 2000) will illustrate the possibilities and limits of the EPI for the respective experimental conditions. Results show that the epiphaniometer (EPI) provided reliable particle surface area concentrations with a minimal time resolution of 15 minutes and that the correlation to the DC was generally better for on-road truck chase experiments than for the other steady state experiments, despite the high (but short) peak concentrations during the first experiment type.