Growth and neutralization of sulfate aerosols in human airways.
Sarangapani, Ramesh, and Anthony S. Wexler.
DEPARTMENT OF MECHANICAL ENGINEERING, UNIVERSITY OF DELAWARE,
NEWARK, DELAWARE 19716-3140, PHONE : (302) 831-8743, FAX : (302) 831
-3619
APStracts 3:0103A, 1996.
Evidence derived from in vivo and in vitro laboratory experiments,
controlled human exposure studies, and epidemiological studies on
mortality and morbidity all point to a positive correlation between
acid aerosol inhalation and lung impairment. The lung has two
important lines of defense against acid aerosols (i) neutralization
by oral or nasal airway ammonia, and (ii) buffering by mucus lining
of the airway. In this paper a mathematical model is developed to
study the growth and endogenous ammonia neutralization of sulfate
containing aerosol particles in the human respiratory tract. It is
shown that an accurate prediction of the luminal ammonia
concentration and relative humidity in each generation is essential
for quantifying the degree of neutralization of the acidic particles.
The model predicts substantial growth and neutralization for small
particles (< 0.1) while larger particles (> 1.0) experience
negligible neutralization. The predicted neutralization of
intermediate-sized particles depends on the parameter values used in
the model. Water supersaturations that occur in the respiratory tract
when ambient conditions are cool and humid cause rapid particle
growth and consequently enhance neutralization. Thus the
neutralization depends on the particle size as well as ambient
conditions.
Received 26 October 1994; accepted in final form 7 February 1996.
APS Manuscript Number A1100-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 24 February 96