Evaluation of methods for the determination of diesel-generated fine particulate matter: Physical characterization results

A multi-phase instrument comparison study was conducted on two different diesel engines on a dynamometer to compare commonly used particulate matter (PM) measurement techniques while sampling the same diesel exhaust aerosol and to evaluate inter- and intra-method variability. Included in this evaluation were a Tapered Element Oscillating Microbalance (TEOM), three Scanning Mobility Particle Sizers (SMPSs), a Condensation Particle Counter (CPC), a TSI DustTrak, a MET-One E-BAM, and two Electrical Low Pressure Impactors (ELPIs) as well as two types of time-integrated filter samplers. Of the five on-line analyzers evaluated for PM mass concentration, the TEOM was shown to have the best overall correlation to the gravimetric filter method. For measuring concentration by particle number, the two ELPIs and the Model 3936L25 SMPS provided generally comparable results during both test phases (data for the stand-alone CPC were invalidated). With respect to measuring particle size distribution (PSD) by gravimetric analysis, the ELPIs were not found to be useful for a variety of reasons whereas for differential number distribution, the SMPSs and ELPIs provided generally comparable results.