This project is a cooperative effort between Brigham Young University (BYU) and researchers from the DOE-NETL Office of Science and and Engineering Research to determine the contribution of semi-volatile particulate organic compounds (SVOC) to total ambient suspended fine particulate mass at the NETL-Pittsburgh air monitoring facility. Project funding comes from DOE‘s University Coal Research (UCR) program.

The hypothesis of the project is that fine particulate mass will be significantly under-determined in urban environments using single filter samplers such as the PM2.5 Federal Reference Method (FRM) because of the loss of semi-volatile organic compounds (SVOC) from the particles during sampling and storage. It is postulated that fine particulate mass, including the semi-volatile fine particulate organic species, are an appropriate surrogate for the components of fine particles which are associated with observed mortality and morbidity effects in epidemiological studies. Further, it is postulated that the most important fraction of the semi-volatile organic material with respect to exacerbation of health problems will be semi-volatile secondary compounds formed from reactions of volatile organic material with ozone and nitrogen oxides. Under-determination of these semi-volatile species will tend to over emphasize the importance of non-volatile fine particulate components such as sulfate or may reduce the significance of correlations with measured health effects.

Data were obtained at the NETL facility in Pittsburgh from November 1999 through December 2000 to identify the daily contribution of semi-volatile organic material to ambient PM2.5 and determine the meteorological conditions that are associated with formation of high concentrations of fine particulate SVOC. During the first year's sampling program, a PC-BOSS particle concentrator diffusion denuder sampler was used for the determination and characterization of fine particulate mass, including semi-volatile organic material lost from fine particles during sampling with a filter. Compositions of the collected fine particles (sulfate, nitrate, acidity, ammonium ion, semi-volatile and non-volatile organic material, and soot) are being determined for samples collected to date. The results obtained during this period are being compared to results found by the EPA.

In the second year of the project, analysis of selected samples for N-nitroso and nitrite containing SVOC will be performed. Correlations among the semi-volatile and non-volatile constituents and meteorological conditions will be established. Samples collected during meteorological conditions that lead to high SVOC will be analyzed to determine the diurnal variations in concentrations of SVOC and N-nitroso-, nitro, nitrite- and nitrate- containing non-volatile and semi-volatile organic material.

These experiments will quantify the semi-volatile organic species lost from particles using conventional single filter samplers, identify the conditions under which substantial amounts of SVOC are present in PM2.5 and determine conditions which lead to the presence of substantial amounts of potentially toxic NOx -SVOC material in ambient fine particles. This information should allow a better assessment of the role that these major fine particulate species may play in the etiology of mortality and morbidity effects associated with exposure to fine particles. This will allow for the development of appropriate attainment strategies, the collection of better exposure data and an improvement in risk assessment analyses.