Mass concentrations and metals speciation of PM2.5, PM10, and total suspended solids in Oxford, Ohio and comparison with those from metropolitan sites in the Greater Cincinnati region

Ambient aerosols were sampled for a period of 12 months from January to December 2005 in Oxford, OH, which is a relatively small college town approximately 50 miles northwest of Cincinnati. The goal of this study was to compare the mass concentrations and metals speciation of ambient aerosols collected in Oxford, OH with those collected in three urban centers (Cincinnati, Middletown, and Hamilton) in the Greater Cincinnati region. A secondary goal was to compare the effects of meteorological conditions on PM2.5 and PM10. Three different sampling instruments were used to collect PM2.5, PM10, and total suspended solids (TSP) in Oxford.It was found that PM2.5 mass concentrations in Oxford were approximately 10% lower than those measured in Cincinnati, Middletown, and Hamilton. It was also found that the PM2.5 contributed ∼95% to PM10 and >60% to TSP. Acid extraction of the filters followed by inductively coupled plasma (ICP) was used for metals speciation. It was found that arsenic, antimony, cobalt, and lead were predominantly contained in PM2.5, whereas cadmium, chromium, iron, nickel, molybdenum, silicon, vanadium, and zinc were found predominantly in PM10. The crustal elements, including aluminum, calcium, magnesium, manganese, and potassium, were found predominantly in TSP. Copper had relatively high concentrations in TSP samples in Oxford, which may be due to emissions from a local industry that manufactures copper-based products. The metals concentrations in Oxford were generally lower than those reported in for Cincinnati and Middletown. However, different analytical methods were used for metals speciation in those cities, which likely contributed significantly to observed differences.It was observed that PM concentrations increased with air temperature and decreased with increasing wind speed. Humidity, precipitation, and wind direction appeared to have very little effect on PM concentrations.