HR: 0800h
AN: A31A-0813    [Abstracts]
TI: Investigating the causes of airborne dust in Western United States
AU: * Kavouras, I G
EM: ilias.kavouras@dri.edu
AF: Desert Research Institute, 755 E.Flamingo Rd, Las Vegas, NV 89119 United States
AU: Etyemezian, V
EM: vic@dri.edu
AF: Desert Research Institute, 755 E.Flamingo Rd, Las Vegas, NV 89119 United States
AU: Xu, J
EM: jin.xu@dri.edu
AF: Desert Research Institute, 755 E.Flamingo Rd, Las Vegas, NV 89119 United States
AU: DuBois, D
EM: Dave.DuBois@dri.edu
AF: Desert Research Institute, 755 E.Flamingo Rd, Las Vegas, NV 89119 United States
AU: Pitchford, M
EM: Marc.Pitchford@noaa.gov
AF: NOAA Air Resources Laboratory, 755 E. Flamingo Rd, Las Vegas, NV 89119 United States
AU: Green, M
EM: Mark.Green@dri.edu
AF: Desert Research Institute, 755 E.Flamingo Rd, Las Vegas, NV 89119 United States
AB: Dust is a principal component of haze at many of the Western Class I Areas as defined by the Clean Air Act (CAA) adopted by the US congress on 1977. The magnitude of the impact of dust on haze varies by region as well as by season due to source variations in spatial scale, time, location, and causes of emission. Windblown dust emissions occur on both local and regional scales and the magnitude of dust emissions depends on man-made activities, soil properties and meteorology. On a transcontinental scale, enormous, regional dust storms can be transported across oceans and continents and impact the entire western United States. The target of this study was to specifically identify the causes of dust measured in the Class I areas of the western states by developing a methodology for assigning worst-case visibility days when dust was the major component at IMPROVE monitors within the WRAP domain to a set of source-categories over the period 2001 - 2003. The methodology included the development and implementation of the following tools: (i) concentration diagnostic ratios; (ii) multivariate linear regression analysis; (iii) air masses backward trajectories analysis; (iv) land use characteristics and; (v) soil properties. Each day was attributed to: (i) Transcontinental transport of large scale events from Asia; (ii) Small scale local windblown dust events; (iii) A combination of local and regional windblown dust events; (iv) Upwind transport and (v) Other unknown sources. The study included 71 sites from the IMPROVE network located in the Western Regional Air Partnership (WRAP) domain. Meteorological data including wind speed and direction and, precipitation (if available) were retrieved from meteorological stations in the vicinity of the IMPROVE monitors and used to estimate the contribution of "locally" generated windblown dust to visibility impairment. The spatial and temporal variation of the number of days attributed to the aforementioned source-categories was examined.
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: Fall Meeting 2005