[On the effect of odourants in laboratory and field tests (author's transl)]

Odour nuisance reactions are of considerable importance in environmental hygiene. Their scientific analysis calls for a high degree of flexibility in the selection of adequate "access routes". The present paper deals with results of laboratory and field investigations in conjunction with the problem of odour pollution. In a laboratory test 50 test subjects were exposed for 2 1/2 hours either to H2S stimuli at a level of about 2.5 ppm or to pure air. The following effects were investigated: perception and evaluation of stimuli, subjective feeling as well as ability to concentrate. As expected, perceived intensity and intolerance of the stimulus decreased linearly with the duration of exposure; the subjective feeling and concentration were not significantly affected by smell as was demonstrated by comparative checks. By contrast, field investigations of differently exposed groups of population clearly demonstrated negative effects of odour pollution. 704 inhabitants of the city of Düsseldorf, residing in control and exposed areas, were given standardised questionnaires by interviewers to obtain information on reactions to offensive smell. The multivariate data analysis produced a 3-factor reaction pattern, with factor I (general reaction to offensive smell on a sensory basis) being particularly discriminatory. Moreover, it was found that, under identical exposure conditions, persons with a low adaptive tolerance professed themselves to be much more disturbed by the smell than did others with a higher degree of adaptive tolerance to the nuisance. A comparison of the laboratory findings with the field values suggests that the scientific analysis of reactions to the smell pollution presupposes an existential engagement of the examinee which requires that the disturbing stimulus be "embedded" in the pattern of the daily reality of life. This, of course, can hardly be realized in the laboratory.