Evaluations of EPA Approved FRM PM2.5 and PM10 Samplers

Accurate measurement of particulate matter (PM) concentrations in ambient air is becoming increasingly important as regulatory agencies continue to tighten limits on PM concentrations to which the public may be exposed.  However, previous theoretical research has indicated that significant biases are associated with the use of federal reference method (FRM) PM samplers in the presence of large PM such as that generated by many agricultural operations, including cotton gins.  Furthermore, field sampling has indicated that sampler performance may be affected by external variables such as dust concentrations, dust characteristics, and wind speed.  The objective of this paper is to determine the actual cut-point and slope of two types of EPA-approved FRM PM₁₀ samplers using the controlled conditions of a wind tunnel with poly-disperse dusts having varying particle size distributions (PSDs) at different wind speeds and concentrations.  For both the PM₁₀ inlets analyzed, the cut-points and slopes were not consistently within the acceptable ranges specified by the EPA for FRM PM₁₀ samplers.  The results of this analysis indicate that these samplers are not operating as intended, and industries may be suffering the consequences of inequitable regulation as a result of sampler error.