HR: 1340h
AN: A33D-1544    [Abstracts]
TI: Interactions of Gas-Phase Nitric/Nitrous Acids and Primary Organic Aerosol in the Atmosphere of Houston, TX
AU: * Ziemba, L D
EM: lziemba@unh.edu
AF: University of New Hampshire, 39 College rd., Durham, NH 03824,
AU: Griffin, R J
EM: rjg@gust.sr.unh.edu
AF: University of New Hampshire, 39 College rd., Durham, NH 03824,
AU: Dibb, J E
EM: jack.dibb@unh.edu
AF: University of New Hampshire, 39 College rd., Durham, NH 03824,
AU: Anderson, C H
EM: caseyhanderson@yahoo.com
AF: University of New Hampshire, 39 College rd., Durham, NH 03824,
AU: Whitlow, S I
EM: sallie.whitlow@gmail.com
AF: University of New Hampshire, 39 College rd., Durham, NH 03824,
AU: Lefer, B L
EM: blefer@uh.edu
AF: Univeristy of Houston, 312 SR-1, 4800 Calhoun Road, Houston, TX 77204,
AU: Flynn, J
EM: jhflynn@mail.uh.edu
AF: Univeristy of Houston, 312 SR-1, 4800 Calhoun Road, Houston, TX 77204,
AU: Rappenglück, B
EM: brappenglueck@uh.edu
AF: Univeristy of Houston, 312 SR-1, 4800 Calhoun Road, Houston, TX 77204,
AB: Concentrations of aerosol and gas-phase pollutants were measured on the roof of an 18-story building during the Texas Air Quality Study II Radical and Aerosol Measurement Project (TRAMP) from August 15 through September 28, 2006. Aerosol measurements included size-resolved, non-refractory mass concentrations of ammonium, nitrate, sulfate, chloride, and organic aerosol in submicron particles using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS). Particulate water-soluble organic carbon (PWSOC) was quantified using a mist chamber/total organic carbon analysis system. Concentration data for gas-phase pollutants included those for nitric acid (HNO3), nitrous acid (HONO), and hydrochloric acid (HCl) collected using a mist chamber/ion chromatographic technique, oxides of nitrogen (NOx) collected using a chemiluminescent method, and carbon monoxide (CO) collected using an infrared gas correlation wheel instrument. Coincident increases in nitrate and organic aerosol mass concentrations were observed on many occasions throughout the measurement campaign, most frequently during the morning rush hour. Based on the lack of organic aerosol processing (defined by the ratio of m/z = 44/57 in the Q-AMS spectra), strong correlation with NOx and CO, and a lack of significant increase in PWSOC concentration, the spikes in organic aerosol were likely associated with primary organic aerosol (POA). During these events, gas-phase HNO3 concentration decreases were observed simultaneously with increases in gas-phase HONO concentrations. These data likely indicate uptake of HNO3 and subsequent heterogeneous conversion to HONO involving POA. Preliminary calculations show that HNO3 partitioning could account for the majority of the observed HONO and aerosol nitrate concentrations during these events. Q-AMS chloride and HCl data also indicate uptake of chloride by particles during these events. This phenomenon was also observed during the night, but these nocturnal events were less frequent and less distinct.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting