||Ambient Sulfate Aerosol Deposition in Man: Modeling the Influence of Hygroscopicity.
Martonen, T. B. ;
Barnett, A. E. ;
Miller, F. J. ;
||Health Effects Research Lab., Research Triangle Park, NC. ;Northrop Services, Inc., Research Triangle Park, NC.
Air pollution effects(Humans) ;
||Some EPA libraries have a fiche copy filed under the call number shown.
Atmospheric sulfate aerosols (H2SO4, (NH4)2SO4, and NH4HSO4) are of international concern because of their global prevalence and potential irritant or toxic effects on humans. To assess hazards following inhalation exposure, the total dose delivered to the human respiratory tract and its regional distribution must be determined. The mass median aerodynamic diameter of the inhaled aerosol will influence the sites of deposition in the respiratory tract. Atmospheric sulfate aerosols are hygroscopic and will have changing particle sizes and densities as they absorb water vapor in the humid environment of the human respiratory tract. Experimental and theoretical data that describe particle size as a function of temperature and relative humidity were used in computer subroutines of an aerosol deposition model in order to calculate the dose dispersion of H2SO4, (NH4)2SO4, and NH4HSO4 aerosols in man. Different temperature and relative humidity environments that approximately correspond to nasal and oral breathing were studied.