Measurement of Ambient Aerosol Composition During the PMTACS-NY 2001 Using an Aerosol Mass Spectrometer. Part I: Mass Concentrations

Semicontinuous ambient aerosol composition measurements performed during the PMTACS-NY Summer 2001 field campaign in Queens/New York with an aerosol mass spectrometer (AMS, developed by Aerodyne Research Inc.) are described. The measurements include 10 min averages of the nonrefractory sulfate, nitrate, ammonium, chloride, and organic mass concentrations in the particle size range of 50 to approximately 1000 nm. Particlebound water concentrations (i.e., aerosol liquid water content) were estimated from the mass spectral information and local meteorological data. Aggregate semicontinuous AMS mass measurements were compared with those from a TEOM mass monitor that was also deployed at the PMTACS-NY 2001 site. On average, the AMS observed 64% of the total particulate matter mass measured by the TEOM Monitor. Filter and additional semicontinuous particulate sulfate measurements performed simultaneously at the site suggest that the observed discrepancy in mass balance between the two instruments is attributable to a combination of large particles (≥1 μm) lost in the AMS inlet system and the refractory aerosol components not measured by the AMS. Measured diurnal patterns of sulfate, nitrate, organics, and total nonrefractory mass concentrations indicate that elevated PM levels measured during this