Submitted to: Transactions of the ASABE
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/27/2008
Publication Date: 4/10/2008
Citation: Buser, M.D., Wanjura, J.D., Whitelock, D.P., Capareda, S., Shaw, B., Lacey, R. 2008. Estimating FRM PM10 sampler performance characteristics using particle size analysis and collocated TSP and PM10 samplers: Cotton gins. Transactions of the ASABE. 51(2):695-702. Interpretive Summary: In the US, regional air quality compliance with national ambient air quality standards for particulate matter is based on concentration measurements taken by federal reference method samplers. The EPA specifies the performance criteria for these samplers. These performance criteria describe how efficiently various sized particles will pass through the PM10 sampler inlet. It is commonly assumed that these efficiencies are constant for a given type of sampler inlet and that the efficiencies are not affected by the type or size of particulate matter to which it is exposed. The results of this work show that the performance characteristics of the EPA-approved PM10 samplers do shift from those specified by the EPA and are affected by the size of particulate matter to which the samplers are exposed. In this study, these substantial performance criteria shifts resulted in the PM10 samplers over-estimating the true PM10 concentrations by as much as 287%.
Technical Abstract: In the US, regional air quality compliance with national ambient air quality standards (NAAQS) for particulate matter (PM) is based on concentration measurements taken by federal reference method (FRM) samplers. The EPA specifies the performance criteria for the FRM samplers. These criteria for the FRM PM10 samplers are defined as a cutpoint and slope of 10 ± 0.5 um and 1.5 ± 0.1 respectively. It is commonly assumed that the performance characteristics of the FRM PM10 sampler do not vary and are independent of the PM characteristics. Several sources have observed errors in the concentrations measured by the FRM PM10 samplers and have suggested that shifts in the sampler performance characteristics may lead to the observed concentration measurement errors. Limited work has been conducted on quantifying the shift in the performance characteristics of the FRM PM10 sampler operating under field conditions. Recent work at a south Texas cotton gin showed that true PM10 concentrations were 55% of the concentrations measured by the FRM PM10 sampler. If the FRM PM10 sampler was operating within the performance criteria range specified by the EPA, the true concentrations would be within approximately 12% of the concentrations measured by the FRM PM10 sampler. The focus of this work was to quantify the shifts in the cutpoint and slope of the penetration curve of the FRM PM10 sampler. Results show that the cutpoint and slope of the FRM PM10 sampler shift substantially and ranged from 13.8 to 34.5 um and 1.7 to 5.6, respectively, when exposed to large PM as is characteristic of agricultural sources. These shifts in the cutpoint and slope of the FRM PM10 sampler resulted in the over estimation of true PM10 concentrations by 145 to 287%.