|MOORE, KARI - Space Dynamics Laboratory|
|MARTIN, RANDAL - Utah State University|
|BRADFORD, WILLIAM - Space Dynamics Laboratory|
|MARCHANT, CHRISTIAN - Space Dynamics Laboratory|
|JONES, DEREK - Space Dynamics Laboratory|
|WOJCIK, MICHAEL - Space Dynamics Laboratory|
Submitted to: Journal of Environmental Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2014
Publication Date: 10/14/2014
Citation: Moore, K.D., Martin, R.S., Bradford, W.J., Marchant, C.C., Jones, D.S., Wojcik, M.D., Pfeiffer, R.L., Prueger, J.H., Hatfield, J.L. 2014. Derivation and use of simple relationships between aerodynamic and optical particle measurements. Journal of Environmental Engineering. DOI: 10.1061/(ASCE)EE.1943-7870.0000893.
Interpretive Summary: Particle emissions to the atmosphere from a range of human activities are an important component to understanding air quality. Human activities can include manufacturing, energy production (coal), transportation, and agriculture. Reliable and accurate measurement of particulate emissions are critical for monitoring activities and to provide calibration data for particulate emission models used for regulatory purposes. In this study a simple relationship is proposed to convert light measurments of particles to a mass concentration. This relationship is referred to as a mass conversion factor (MCF), and essentially converts optically based (light-based) particle measurements to a mass concentration. It is calculated from filter-based samples and optical particle counter (OPC) data on a daily or sample period basis. This data can serve as a comparison to results from many emission models used to estimate total particulate loadings to the atmosphere from various human activities but in particular agricultural activities. Data from six different experiments from California, Utah, and Idaho were used to develop the MCF that represents different agricultural activities. The variety of data from which this relationship is derived enhances the robustness of this approach. The benefit of this research is the development of an approach that increases the reliability of particulate concentration measurements in the atmosphere near the ground surface. Animal producers and environmental regulators will benefit as greater accuracy in estimating actual emissions will result in better management strategies and regulatory guidelines.
Technical Abstract: A simple relationship, referred to as a mass conversion factor (MCF), is presented to convert optically based particle measurements to mass concentration. It is calculated from filter-based samples and optical particle counter (OPC) data on a daily or sample period basis. The MCF allows for greater temporal and spatial mass concentration information than typical filter-based measurements. Results of MCF calculations from several field studies are summarized. Pairwise comparisons from a collocated study with multiple OPCs and mass samplers suggest the minimum variability of the MCF is 5 to 10%. The variability of the MCF within a sample period during a field study with distributed samplers averaged 17 to 21%. In addition, the precision of the Airmetrics MiniVol Portable Air Sampler for particulate matter (PM) was found to be typically < 10%. Comparisons with federal reference method (FRM) samplers showed that MiniVols yield PM2.5 concentrations essentially equivalent to FRMs with slightly greater deviations from the FRM for PM10 under tested ambient conditions.