Human response to varying concentrations of toluene.

Thirty two males and 39 females aged 31-50 were exposed for 7 h to one of the three following conditions: (1) Clean air, (2) constant exposure to 100 ppm toluene, or (3) a varying exposure with the same time-weighted average, but with peaks of 300 ppm every 30 min. During exposure the subjects exercised in three 15-min periods with a load of 50 to 100 W. Exposure to toluene caused significant (P less than 0.05) complaints about poor air quality, altered temperature and noise perception, increased irritation in the nose and the lower airways, feeling of intoxication, and there were tendencies (P less than 0.1) towards irritation in the throat, headache and dizziness. In the four performance tests there was a tendency towards a lower score in a vigilance test while no effect of toluene exposure was seen in a peg board test, a five choice serial reaction test, or a colour test, indicating only minimal if any effect on the psychomotor or visual performance. There was no difference in the acute effects caused by the exposure containing peak concentrations and by the constant exposure.