Measurement of Both Nonvolatile and Semi-Volatile Fractions of Fine Particulate Matter in Fresno, CA

An intensive sampling campaign was performed in Fresno, CA during December 2003 measuring fine particulate matter including both the semi-volatile and nonvolatile fractions of the aerosol. Both the newly developed R&P FDMS Monitor and a PC-BOSS have been shown to measure total PM _2.5 concentrations including semi-volatile nitrate and organic material. Good agreement was observed between the PC-BOSS and the R&P FDMS Monitor in this study with linear regression analysis resulting in a zero-intercept slope of 1.00 ± 0.02 and an R ² = 0.93. Several real-time measuring systems including the R&P Differential TEOM, the Met One BAMS, and a GRIMM Monitor were also employed and comparisons of total PM _2.5 mass were made with the R&P FDMS Monitor. Agreement among these various monitors was generally good. However, differences were sometimes seen. Reasons for observed differences in the real-time mass measurement systems are explained by the composition and complexity of the measured aerosol, most importantly the composition of semi-volatile material. A newly automated ion chromatographic system developed by Dionex was also field tested and compared to both R&P 8400N Nitrate and integrated PC-BOSS inorganic species measurements. Sulfate and nitrate determined by the Dionex and PC-BOSS systems agreed. However, nitrate measured by the 8400N was low during fog events compared to the other two systems.

Appreciation is expressed for the assistance of the California Air Resource Board in Fresno CA and EPA Fresno Supersite. Special thanks is given to Scott Scheller for his assistance during the study and Bill Roe with GRIMM technologies for his help. The U.S. Environmental Protection Agency (EPA) funded and collaborated in the research described under grant 3C-R044-NAEX to Brigham Young University. This study was also jointly funded as part of the U.S. EPA Supersite program under STAR Grant R831086. The views expressed in this paper are those of the authors and do not reflect the views or policies of the United States government or EPA. Mention of trade names and commercial products does not constitute endorsement.

Notes

^a Slopes are given for (1) linear regression zero intercept, (2) linear regression calculated intercept, and (3) orthogonal regression.

^a Slopes are given for (1) zero intercept, (2) calculated intercept, and (3) orthogonal regression.

^b Two Statistical Outliers were not included in the analysis.