HR: 16:30h
AN: A14B-03 INVITED     [Abstracts]
TI: Effects of Transport and Processing on Aerosol Chemical and Optical Properties Across the Gulf of Maine
AU: * Quinn, P
EM: patricia.k.quinn@noaa.gov
AF: NOAA PMEL, 7600 Sand Point Way NE, Seattle, WA 98115
AU: Bates, T
EM: tim.bates@noaa.gov
AF: NOAA PMEL, 7600 Sand Point Way NE, Seattle, WA 98115
AU: Baynard, T
EM: tahllee.baynard@noaa.gov
AF: NOAA AL, 325 Broadway, Boulder, CO 80305
AU: Onasch, T
EM: onasch@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821
AU: Coffman, D
EM: derek.coffman@noaa.gov
AF: NOAA PMEL, 7600 Sand Point Way NE, Seattle, WA 98115
AU: Covert, D
EM: dcovert@u.washington.edu
AF: University of Washington, 4909 25th Ave NE, Seattle, WA 98195
AU: Worsnop, D
EM: worsnop@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821
AU: Goldan, P
EM: paul.d.goldan@noaa.gov
AF: NOAA AL, 325 Broadway, Boulder, CO 80305
AU: Kuster, B
EM: william.c.kuster@noaa.gov
AF: NOAA AL, 325 Broadway, Boulder, CO 80305
AU: deGouw, J
A14B-03 AF: NOAA AL, 325 Broadway, Boulder, CO 80305
AU: Stohl, A
A14B-03 AF: NILU, P.O. Box 100, Kjeller, N-2027 Norway
AB: NEAQS-ITCT 2004 took place in July and August to study natural and anthropogenic emissions from North America including the processing of gas and particle phase species during transport over the North Atlantic and the resulting impact on air quality and climate. During the experiment, measurements were made onboard the NOAA RV Ronald H. Brown with a ship track that extended from the coast along Cape Cod, MA, Boston, MA and Portland, ME, east into the Gulf of Maine and out to Chebogue Point, Nova Scotia. Although measurements on the ship were not made in a true Lagrangian sense, they reveal information about the effects of transport and processing on aerosol chemical and optical properties. Photochemical age based on measured toluene to benzene ratios can be used in this region to indicate 'younger' versus 'older' aerosol. This approach, coupled with FLEXPART estimates of source contributions and age, reveals that continental aerosol becomes more acidic as it ages with transport over the Gulf of Maine. The increasing acidity is due to the conversion of SO2 to SO4= with no further significant input of NH3 in the well-capped marine boundary layer to neutralize the aerosol. In addition, as the aerosol ages, the organic mass fraction decreases while the organics that are present become more oxidized. These same chemical features were observed in aerosol transported from the Ohio River Valley and beyond. In contrast, recently formed aerosol from urban centers along the Eastern Seaboard are neutralized, have a higher organic content, and the organics are less oxidized. The impact of the observed range of aerosol acidity, organic mass fraction, and degree of oxidation of the organic matter on the f(RH) of the aerosol will be described. Here, f(RH) refers to the dependence of light extinction on relative humidity.
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005