Aerosol Source Sampling in a Mid-scale City, Gainesville, FL

Abstract

Five major sources for the ambient aerosol in Gainesville, FL were sampled by using a Micro-Orifice Uniform Deposit Impactor (MOUDI) and a University of Washington Mark III Cascade Impactor. The samples were analyzed for carbons and ions. Soil dust, unpaved road dust, cement dust particles and marine aerosols were mainly in the coarse mode, while particles from transportation showed a bi-modal or tri-modal distribution. Carbon in soil dust was mainly organic, while carbon in unpaved road dust was mainly elemental. In transportation aerosols, carbons were mostly found in the ultra-fine range (< 0.18 μm) and were likely from gasoline vehicles. For ionic species, soil dust was rich in Na+, Cl-, K+, NH4+, and Ca2+. In unpaved road dust, Ca2+ was the dominant species followed by NO3- and K+. Marine aerosols were predominantly Na+ and Cl-, and they were found primarily in the coarse mode. The major ionic species in the fine mode of the transportation aerosols were NH4+ and SO42-, while Na+, Ca2+, and Cl- were the key components in the coarse mode. In the cement dust, Ca2+ was the dominant species.