COMPARATIVE EVALUATION OF AMBIENT FINE PARTICULATE MATTER (PM2.5) DATA OBTAINED FROM URBAN AND RURAL MONITORING SITES ALONG THE UPPER OHIO RIVER VALLEY

Abstract

The report discusses the following conclusions: (1) The TEOM equipment performed as well as the sequential filter samplers in accounting for ambient PM{sub 2.5} levels; however, the FRM-obtained data was consistently lower than the averages from the TEOM/DRI-SFS measurements; (2) The trending in the PM{sub 2.5} levels was similar for Lawrenceville and Holbrook, which represent an urban and a rural site sixty-five miles apart. This implies that the PM{sub 2.5} levels appear to be impacted more by regional than by local effects; (3) The absolute median PM{sub 2.5} levels were slightly higher for Lawrenceville than for Holbrook, implying that local urban environmental contributions had a minor but measurable effect on total PM{sub 2.5} mass concentration; (4) PM{sub 2.5} and PM{sub 10} mass concentration levels were consistently higher in summer than in winter, with intermediate levels observed in the spring and fall; (5) Sulfate levels predominated in the speciation data obtained from both the Holbrook and the Lawrenceville sites during winter and summer intensive sampling. Sulfate level measured at Holbrook were higher than those taken at Lawrenceville regardless of the season; (6) Ammonium levels remained relatively constant between seasons and between sites; (7) Nitrate levels measured at Lawrenceville were higher than those measured at Holbrook during winter intensive sampling. Nitrate levels measured during the summer intensive period were found to be very low at both locations; (8) In general, the predominant inorganic fraction of the samples analyzed could be described as being composed of a mixture of ammonium bisulfate and ammonium sulfate with minor amounts of ammonium nitrate; (9) The PM10 fraction had a larger percentage of geological material and a smaller percentage of condensable material (ammonium bisulfate, ammonium sulfate, ammonium nitrate and total carbon species) than the PM{sub 2.5} fraction for samples collected in winter at Lawrenceville; and (10) Most high PM{sub 2.5} episodes occurred when the predominating wind direction was from the South-West. (11) Plots of ozone vs. NO{sub x} suggest chemical reaction between these molecules since a high concentration of one always results in a low concentration of the other. The analysis of the acquired data has so far addressed three of the four scientific questions originally posed. More data analysis is on-going including the correlation between O{sub 3} and PM{sub 2.5} levels and the correlation of mass data with meteorological observations.