A field comparison of PM10 inlets at four locations
A comprehensive field study was conducted comparing the performance of PM10 inlets under a variety of field conditions. Inlets for low flow, medium flow, and high flow samplers were evaluated at four sampling locations providing a range of concentrations and particle sizes. Sampler precisions were determined at each location along with the regression parameter estimates comparing sampler types. The daily distributions of mass by aerodynamic diameter were measured using the Wide Range Aerosol Classifier and the composited data reported. The expected mass concentrations were calculated using the sampler effectiveness data and the size distributions and then compared to the measured values. This permitted examination of the utility of the proposed Federal Reference Method (FRM) approach for specifying PM10 samplers. The comparison results indicate that the precisions of the PM10 samplers are well within the FRM requirements. The performance of the inlets as characterized by wind tunnel testing provided computed results which in most cases were within ±10% of the measured values. Exceptions included the Sierra/Andersen Model 321 hi-vol inlet, which appears to significantly overcollect as the result of dry particle bounce, and the GMW 9000 hi-vol inlet, which appears to significantly undercollect, perhaps as the result of the internal surfaces becoming dirty.