The eye irritation and odor potencies of four terpenes which are major constituents of the emissions of VOCs from Nordic soft woods.

Eye goggles were used to estimate human thresholds for sensory eye irritation from four monoterpenes: (+)3-carene, (-)limonene and (+)alpha-pinene and (rac)alpha-terpineol all known as air pollutants emitted from wood. Only a ranking of the irritation thresholds relative to that of n-butanol is given. The measurements showed that the thresholds for eye irritation of the terpenes ranged from subthreshold to below 1,250 mg/m3. It appears that the irritation of 3-carene and limonene in contrast to the expectations was of the same size as or less than that of n-butanol. Too few subjects reported eye-irritation for alpha-pinene and alpha-terpineol to allow estimates of thresholds of these compounds which therefore have much less irritative potency than n-butanol, 3-carene, and limonene. The measurements of one terpene alcohol do not support the hypothesis that monoterpene alcohols, would have lower eye irritation threshold than monoterpene hydrocarbons. The sequence from strongest odorant to weakest was alpha-terpineol, 3-carene, n-butanol, limonene and alpha-pinene. In conclusion, the tested terpenes can probably be ruled out as cause of acute eye irritation indoors. The measured odor thresholds did not deviate from the few values reported in the literature.