Context: Acrolein is a reactive aldehyde mainly formed by combustion. The critical effect is considered to be irritation of the eyes and airways; however, the scarce data available make it difficult to assess effect levels.
Objective: The aim of the study was to determine thresholds for acute irritation for acrolein.
Methods: Nine healthy volunteers of each sex were exposed at six occasions for 2 h at rest to: clean air, 15 ppm ethyl acetate (EA), and 0.05 ppm and 0.1 ppm acrolein with and without EA (15 ppm) to mask the potential influence of odor. Symptoms related to irritation and central nervous system effects were rated on 100-mm Visual Analogue Scales.
Results: The ratings of eye irritation were slightly but significantly increased during exposure to acrolein in a dose-dependent manner (p < 0.001, Friedman test) with a median rating of 8 mm (corresponding to "hardly at all") at the 0.1 ppm condition and with no influence from EA. No significant exposure-related effects were found for pulmonary function, or nasal swelling, nor for markers of inflammation and coagulation in blood (IL-6, C-reactive protein, serum amyloid A, fibrinogen, factor VIII, von Willebrand factor, and Clara cell protein) or induced sputum (cell count, differential cell count, IL-6 and IL-8). Blink frequency recorded by electromyography was increased during exposure to 0.1 ppm acrolein alone but not during any of the other five exposure conditions.
Conclusion: Based on subjective ratings, the present study showed minor eye irritation by exposure to 0.1 ppm acrolein.
Keywords: Human exposure; indoor air; induced sputum; inflammation; irritation; smell; subjective ratings.