Acute response to 3.0 ppm formaldehyde in exercising healthy nonsmokers and asthmatics

Formaldehyde is an ubiquitous industrial and indoor air pollutant to which millions are daily exposed. Because of the paucity of scientific data concerning the inhalation toxicity of this compound in humans, we determined the symptoms and alterations in pulmonary function resulting from inhalation for 1 h of 3 parts per million formaldehyde in a controlled environmental chamber. The protocol consisted of randomized exposure of each subject to clean air or 3.0 ppm HCHO on 2 separate days. Twenty-two healthy normal subjects engaged in intermittent heavy exercise (V̇(E) = 65 L/min) and 16 asthmatic subjects performed intermittent moderate exercise (V̇(E) = 37 L/min). Symptoms and pulmonary function were assessed during the time course of exposure; nonspecific airway reactivity was assessed after exposure. Both groups exhibited similar, significant (p < 0.01) increases in perceived odor, nose/throat irritation, and eye irritation throughout the exposure. The normal group had the following statistically significant (p < 0.02)) lower pulmomary functions after 55 min of exposure to formaldehyde as compared to clean air: 3.8% in FEV₁, 2.6% in FVC, and 2.8% in FEV₃. The asthmatic group showed no statistically significant decrements in pulmonary function. Five of 38 subjects studied had decrements in FEV₁ greater than 10%. In conclusion, acute exposure to 3 ppm HCHO produced: (1) consistent irritant symptoms in both normal and asthmatic subjects, (2) small decreases in pulmonary function in normal subjects engaging in heavy exercise, and (3) clinically significant responses (defined as decrements in FEV₁ greater than 10%) in 13% of the study population. These data suggest that some persons will demonstrate an increased responsiveness to HCHO. The basis of this altered responsiveness is unknown at this time.