ODOR-ANNOYANCE ESTIMATES FROM ROAD-TRAFFIC COMBUSTION EXHAUSTS - CALIBRATION WITH MASTER SCALING USING PYRIDINE AS A REFERENCE

The present field study addressed the need for a procedure that provid es a defined unit of measurement of perceived annoyance from environme ntal odors, calibrating the estimates for individual scaling behavior and context effects. In including 25 subjects, the purpose was to demo nstrate the applicability of the master-scale procedure with magnitude estimation to perform such a calibration of odor-annoyance estimates for target stimuli such as road-traffic combustion exhausts (13 000 ve hicles/d; averaging 47 mu g/m(3) over the day/night with peaks exceedi ng 100 mu g/m(3) of nitrogen dioxide; NO2). For comparison, calibrated estimates were also obtained for a backyard expected to be considerab ly less polluted (comparable with 18 mu g/m(3) of NO2) and for blank s timuli presented indoors. The data transformation for the calibration procedure with which annoyance is expressed in either master-scale uni ts or pyridine equivalents requires estimates of a reference stimulus for which seven concentrations of pyridine were used. The results prov ide an illustration of master scaling of odor annoyance, and imply tha t use of a modulus (standard stimulus with a predefined annoyance magn itude), in contrast to master scaling, is not sufficient for calibrati on for individual scaling behavior and context effects. (C) 1997 Elsev ier Science Ltd.