Publication Abstracts

Gyawali et al. 2012

Gyawali, M., W.P. Arnott, R.A. Zaveri, C. Song, H. Moosmüller, L. Liu, M.I. Mishchenko, L.-W.A. Chen, M.C. Green, J.G. Watson, and J.C. Chow, 2012: Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols. Atmos. Chem. Phys., 12, 2587-2601, doi:10.5194/acp-12-2587-2012.

We present the laboratory and ambient photoacoustic (PA) measurement of aerosol light absorption coefficients at ultraviolet wavelength (i.e., 355 nm) and compare with measurements at 405, 532, 870, and 1047 nm. Simultaneous measurements of aerosol light scattering coefficients were achieved by the integrating reciprocal nephelometer within the PA's acoustic resonator. Absorption and scattering measurements were carried out for various laboratory-generated aerosols, including salt, incense, and kerosene soot to evaluate the instrument calibration and gain insight on the spectral dependence of aerosol light absorption and scattering. Ambient measurements were obtained in Reno, Nevada, between 18 December 2009 and 18 January 2010. The measurement period included days with and without strong ground level temperature inversions, corresponding to highly polluted (freshly emitted aerosols) and relatively clean (aged aerosols) conditions. Particulate matter (PM) concentrations were measured and analyzed with other tracers of traffic emissions. The temperature inversion episodes caused very high concentration of PM2.5 and PM10 (particulate matter with aerodynamic diameters less than 2.5 µm and 10 µm, respectively) and gaseous pollutants: carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO2). The diurnal change of absorption and scattering coefficients during the polluted (inversion) days increased approximately by a factor of two for all wavelengths compared to the clean days. The spectral variation in aerosol absorption coefficients indicated a significant amount of absorbing aerosol from traffic emissions and residential wood burning. The analysis of single scattering albedo (SSA), Ågström exponent of absorption (AEA), and Ågström exponent of scattering (AES) for clean and polluted days provides evidences that the aerosol aging and coating process is suppressed by strong temperature inversion under cloudy conditions. In general, measured UV absorption coefficients were found to be much larger for biomass burning aerosol than for typical ambient aerosols.

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BibTeX Citation

@article{gy01000b,
  author={Gyawali, M. and Arnott, W. P. and Zaveri, R. A. and Song, C. and Moosmüller, H. and Liu, L. and Mishchenko, M. I. and Chen, L.-W. A. and Green, M. C. and Watson, J. G. and Chow, J. C.},
  title={Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols},
  year={2012},
  journal={Atmos. Chem. Phys.},
  volume={12},
  pages={2587--2601},
  doi={10.5194/acp-12-2587-2012},
}

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RIS Citation

TY  - JOUR
ID  - gy01000b
AU  - Gyawali, M.
AU  - Arnott, W. P.
AU  - Zaveri, R. A.
AU  - Song, C.
AU  - Moosmüller, H.
AU  - Liu, L.
AU  - Mishchenko, M. I.
AU  - Chen, L.-W. A.
AU  - Green, M. C.
AU  - Watson, J. G.
AU  - Chow, J. C.
PY  - 2012
TI  - Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols
JA  - Atmos. Chem. Phys.
VL  - 12
SP  - 2587
EP  - 2601
DO  - 10.5194/acp-12-2587-2012
ER  -

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