HR: 09:45h
AN: A41E-08    [Abstracts]
TI: A Tale of two Cities: Photoacoustic and Aethalometer Measurements Comparisons of Light Absorption in Mexico City and Las Vegas, NV, USA
AU: * Paredes-Miranda, G
EM: gparedes@physics.unr.edu
AF: Physics and Atmospheric Sciences, UNR, University of Nevada Reno, Physics Dept. MS 220, Reno, NV 89557, United States
AU: Arnott, W P
EM: patarnott@physics.unr.edu
AF: Physics and Atmospheric Sciences, UNR, University of Nevada Reno, Physics Dept. MS 220, Reno, NV 89557, United States
AU: Marley, N A
EM: namarley@uarl.edu
AF: Chemistry Department, UAR, University Of Arkansas, Chemistry 2801 South University Avenue SCLB RM 451, Little Rock, AR 72204, United States
AU: Gaffney, J S
EM: jsgaffney@uarl.edu
AF: Chemistry Department, UAR, University Of Arkansas, Chemistry 2801 South University Avenue SCLB RM 451, Little Rock, AR 72204, United States
AB: As part of the Megacity Impacts on Regional and Global Environments, MIRAGE-Mex deployment to Mexico City in the period of 30 days, March 2006, a suite of photoacoustic spectrometers (PAS; W. Arnott & G. Paredes), nephelometer scattering, and aetholemeter absorption instruments (N. Marley & J.Gaffney) were installed to measure at ground level the light absorption and scattering by aerosols at the urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). This IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm^-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed. The Las Vegas, NV site was located at East Charleston Street on January-February, 2003. In east Las Vegas typical westerly winds carry the city plume across the site. Comparisons of PAS aerosol light absorption and aetholemeter absorption measurements at 521 nm at both Las Vegas NV and Mexico City sites will be presented. We will also present a broad overview of the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the sites in relation to secondary aerosol formation.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly