ABSTRACT
Previous studies have failed to demonstrate bronchoconstriction in unselected asthmatics after brief (less than or equal to 1/2-h), controlled exposures to formaldehyde (HCHO). This study was designed to evaluate the acute pulmonary response to 3 ppm HCHO in nine nonsmoking asthmatic volunteers over a more relevant exposure duration (3 hrs). Pulmonary function, nonspecific airway reactivity and symptoms were assessed before and at intervals during the exposure. No significant changes in pulmonary function (FVC, FEV1, FEF25-27%, SGaw, or FRC) or airway reactivity were observed. There was a significant increase in nose/throat irritation at 30 min. (P less than 0.05) and in eye irritation at 60 min (P less than 0.05) and 180 min (P less than 0.01). These results suggest that individuals with asthma will not experience significant bronchoconstriction when exposed at rest to 3 ppm HCHO; however, most will experience eye and upper respiratory tract irritation.
Subject(s)
Asthma/physiopathology , Formaldehyde/adverse effects , Lung/drug effects , Adult , Atmosphere Exposure Chambers , Female , Humans , Male , Respiratory Function Tests , SpirometrySubject(s)
Formaldehyde/adverse effects , Irritants , Adult , Female , Humans , Male , Maximum Allowable Concentration , Respiratory Function TestsSubject(s)
Ascorbic Acid/therapeutic use , Bronchial Diseases/chemically induced , Ozone/adverse effects , Adult , Bronchial Diseases/physiopathology , Bronchial Diseases/prevention & control , Constriction, Pathologic/chemically induced , Constriction, Pathologic/physiopathology , Constriction, Pathologic/prevention & control , Double-Blind Method , Female , Forced Expiratory Volume , Humans , Male , Methacholine Chloride , Methacholine Compounds , Vitamin E/therapeutic useABSTRACT
The acute pulmonary response to three hours' exposure to 3 ppm formaldehyde (HCHO) during intermittent exercise was evaluated in nine healthy nonsmokers. The protocol consisted of clean air on the first day and HCHO on the second day with a 24-hour follow-up on the third day. Pulmonary function, nonspecific airway reactivity, and symptoms were assessed daily. Thirty minutes of HCHO exposure resulted in a 2% decrease in forced expiratory volume at one second (P less than .05) and a 7% decrease in forced midexpiratory flow rate 25%-75% (P less than .01); however, these effects were no longer present between 60 and 180 minutes. There was also a significant increase in odor (P less than .02), nose or throat irritation (P less than .01), and eye irritation (P less than .01) with exposure. No changes in pulmonary function or airway reactivity were observed 24 hours after exposure. Acute exposure to 3 ppm HCHO produced small, transient decreases in pulmonary function and mild to moderate eye and upper respiratory tract irritation.
Subject(s)
Formaldehyde/adverse effects , Lung/drug effects , Occupational Diseases/chemically induced , Adult , Female , Humans , Male , Plethysmography , Respiratory Function Tests , United StatesABSTRACT
Significant concentration responses were observed in FVC, FEV1, FEF25-75, SGaw, IC, and TLC in 20 healthy, nonsmoking volunteers exposed randomly to 0.00, 0.10, 0.15, 0.20, and 0.25 ppm O3. In addition, significant response changes for FVC, FEV1, and FEF25-75 were shown with time over the 2-h exposure. Intermittent, heavy exercise (VE, 68 L/min) lasting 14 min was employed every 30 min during exposure. Inspection of the concentration and time response curves suggests that the threshold for the group response is at or below 0.15 ppm O3. Six subjects experienced decreases greater than 5% in FEV1 or greater than 15% in SGaw at 0.15 ppm. This concentration is only slightly higher than the 1-h O3 National Ambient Air Quality Standard. A dose-related response was also seen for cough, nose and throat irritation, and chest discomfort. The work load, length of exposure, and individual sensitivity must be considered for establishing a safe O3 exposure level.
