Acid fog, composed chiefly of H2SO4 and HNO3, occurs on a seasonal basis in Los Angeles and elsewhere in the country. The following physicochemical properties of acid fog have been reported: pH as low as 1.7, total acid mass in excess of 100 ug/m3, hypo-osmolar liquid water content of about 0.2 g/m3, and a mass median diameter of the fog droplets on the order of 15 um. We hypothesize that these fog droplets are irritating to the respiratory system.
Our specific aims are to generate and characterize H2SO4-fog for the acute exposure of human volunteers. The fog will be administered in a small-volume head dome. Two groups of adults will be studied: healthy non-smokers and asthmatics. The functional end-points will include: airway reactivity, maximal expiratory flow-volume curves, respiratory flow resistance, and bronchopulmonary deposition and clearance of a radiolabeled aerosol. The possible roles of post-ganglionic nerve stimulation and mast cell mediator release in the response to acid fog will be studied.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES003871-03
Application #
3251631
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1986-07-01
Project End
1990-06-30
Budget Start
1988-07-01
Budget End
1990-06-30
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Type
Schools of Public Health
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Bowes 3rd, S M; Francis, M; Laube, B L et al. (1995) Acute exposure to acid fog: influence of breathing pattern on effective dose. Am Ind Hyg Assoc J 56:143-50
Laube, B L; Bowes 3rd, S M; Links, J M et al. (1993) Acute exposure to acid fog. Effects on mucociliary clearance. Am Rev Respir Dis 147:1105-11
Bowes 3rd, S M; Frank, R; Swift, D L (1990) The head dome: a simplified method for human exposures to inhaled air pollutants. Am Ind Hyg Assoc J 51:257-60
Bowes 3rd, S M; Laube, B L; Links, J M et al. (1989) Regional deposition of inhaled fog droplets: preliminary observations. Environ Health Perspect 79:151-7