HR: 1340h
AN: A53A-0171    [Abstracts]
TI: Analysis of the Effects of Chemical Composition and Humidity on Visibility using Highly Time Resolved Aerosol Data
AU: Lunden, M M
EM: MMLunden@lbl.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Rd. MS 90K0198, Berkeley, CA 94720-8121 United States
AU: Brown, N J
EM: NJBrown@lbl.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Rd. MS 90K0198, Berkeley, CA 94720-8121 United States
AU: Liu, D
EM: De-Ling.Liu@jpl.nasa.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Rd. MS 90K0198, Berkeley, CA 94720-8121 United States
AU: * Tonse, S
EM: stonse@lbl.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Rd. MS 90K0198, Berkeley, CA 94720-8121 United States
AB: Transported aerosols from populated and industrial areas result in regional haze that causes visibility degradation in areas valued for their scenic beauty, such as the National Parks. These areas are designated as Class I Areas in the United States, and there are specific visibility goals put forth to ultimately return these areas to natural conditions. To both understand current conditions and chart progress towards meeting these goals requires measurement of important aerosol species and an understanding of how these different aerosol species affect light attenuation to allow for predictive modeling capabilities. The current investigation seeks to understand if more highly time resolved measurements of chemically speciated particle mass, relative humidity, scattering, and absorption would enable a better estimation of extinction as the relationship between these variables is non-linear. Our particular objective is to explore the contributions of the aerosol species mentioned above to visibility degradation, and the role played by relative humidity. We performed analyses on a data set collected in Central California from the intensive ambient aerosol sampling campaign conducted from 2000 summer-2001 winter¹. The data include PM-2.5 mass concentrations of nitrate, sulfate, organic carbon and black carbon aerosol, as well as simultaneous measurements on light scattering, ambient temperature and relative humidity. The dataset is highly time-resolved, allowing the affect of temporal variations of particle chemical composition and meteorological features to be considered. The final results provide response curves that allow calculation of light scattering given aerosol concentrations and relative humidity. Our results are compared with those obtained using formulae suggested for analysis of IMPROVE (a regional haze monitoring network²) data collected under lower temporal resolution to understand the effects of temporal resolution on the characteristics of the relationships among extinction, aerosol loading and type, and relative humidity. References 1. Lunden, M.M., T.L. Thatcher, S.V. Hering, and N.J. Brown (2003). The Use of Time- and Chemically-Resolved Particulate Data to Characterize the Infiltration of Outdoor PM-2.5 into a Residence in the San Joaquin Valley. Environmental Science and Technology 37, pp 4724-4732. 2. Malm, W.C., 'IMPROVE, Interagency Monitoring of Protected Visual Environments,' ISSN: 0737-5352-47, Colorado State University, May 2000.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005