Research Projects

The projects completed under this contract permit the following conclusions:

1. The particle size of sulfuric acid aerosols does not appear to be a major determinant of their bronchoconstrictor potency.

2. One previous finding that acidity potentiates the bronchoconstrictor effect of hypoosmolar aerosols with high liquid water content in subjects with asthma was not replicated when aerosols of much lower liquid water content were studied.

3. Clinically significant bronchoconstriction did not occur in subjects with mild-moderate asthma exposed to sulfuric acid aerosols while at rest. However, this finding does not rule out the possibility that significant bronchoconstriction may occur under other conditions, e.g., with exposure during exercise.

4. There does not appear to be a significant positive interaction between acidity and cold temperature with regard to the potentiation of hypoosmolar aerosol-induced bronchoconstriction in subjects with asthma.

5. Since acidity and cold temperature did not interact positively with regard to the potentiation of bronchoconstriction, it should not be necessary to generate acid fogs at low temperature in exposure chamber studies.