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Ozone-induced changes in pulmonary function and bronchial responsiveness in asthmatics
J W Kreit1, K B Gross, T B Moore
1Division of Pulmonary and Critical Care Medicine, University of Michigan Medical Center, Ann Arbor 48109.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|January 1, 1989
Summary
High ozone exposure significantly increases airway responsiveness in both normal and asthmatic individuals. Asthmatics experience greater airflow obstruction compared to healthy subjects after ozone exposure.
Area of Science:
- Environmental Health
- Pulmonary Medicine
- Toxicology
Background:
- Ozone is a significant air pollutant with known respiratory effects.
- Asthma is a chronic inflammatory airway disease characterized by hyperresponsiveness.
Purpose of the Study:
- To compare the respiratory responses of asthmatic and normal subjects to high ozone concentrations.
- To assess changes in pulmonary function and bronchial responsiveness following ozone exposure.
Main Methods:
- Nine asthmatic and nine normal subjects were exposed to filtered air and 0.4 ppm ozone for 2 hours.
- Alternating rest and exercise periods (minute ventilation = 30 L/min/m²) were employed.
- Pulmonary function tests (FVC, FEV1, FEV1%, FEF25-75) and methacholine responsiveness were measured pre- and post-exposure.
Main Results:
- Ozone exposure significantly decreased FVC, FEV1, FEV1%, and FEF25-75 in both groups.
- Asthmatic subjects showed a significantly greater percentage decrease in FEV1, FEV1%, and FEF25-75 compared to normal subjects.
- Both groups exhibited increased bronchial responsiveness to ozone, with similar symptom scores and lung volume changes.
Conclusions:
- High ozone exposure increases bronchial responsiveness in both healthy and asthmatic individuals.
- Asthmatic subjects experience more severe airway obstruction than normal subjects when exposed to ozone.
- Ozone exposure affects lung volumes and symptoms similarly across both groups, despite differential effects on airflow obstruction.