You are here:
DEPOSITION OF SULFATE ACID AEROSOLS IN THE DEVELOPING HUMAN LUNG
Citation:
Martonen, T. AND J. Hester. DEPOSITION OF SULFATE ACID AEROSOLS IN THE DEVELOPING HUMAN LUNG. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/401 (NTIS PB93236388), 1993.
Description:
Computations of aerosol deposition as affected by (i) aerosol hygroscopicity, (ii) human age, and (iii) respiratory intensity are accomplished using a validated mathematical model. he interactive effects are very complicated but systematic. ew general observations can be made; rather, the findings presented within should be addressed on a case-by-case basis. he behavior of inhaled H2SO4 particles subsequent to water vapor uptake significantly influences their total deposition values and relative spatial distribution patterns within tracheobronchial and pulmonary airways. hese observations must be accounted for in risk assessment protocols since compartment.s of the lung have different clearance processes and sensitivities to toxic materials. here is a critical size in the 0.2 - 0.4 um range: for larger particles the influence of hygroscopicity is to increase total deposition whereas for smaller particles the opposite occurs. he magnitudes of hygroscopic effects can be pronounced; for example, the deposition of 1 um particles increases from = 0.1 to = 0.5 in the adult lung for resting conditions. alculations also establish that subject age and physical activity are critical variables to be incorporated into health effects studies. hese are of particular importance since children are a sensitive sub-population in risk assessment protocols and adult work/exercise levels must be integrated with inhalation exposures to airborne contaminants. he dosimetric model was developed to provide a scientific basis for extrapolation modeling of factors (i), (ii), and (iii) in the hazard evaluation of airborne contaminants.