Irritation and odor as indicators of indoor pollution.

Both irritation and odor figure prominently in complaints about indoor air. Irritation poses the greater problem since it arguably represents an adverse health effect per se and since its sources are often difficult to locate. There exist various potential assays for irritation, some better for validation of symptoms and some better for research on structure-activity relations. One animal assay, the respiratory depression technique, has produced measures of irritant potency in good accord with sensory psychophysical measurements in humans. Both the animal and human data point toward common physicochemical determinants of potency, especially for the weak irritants that often exist in indoor environments. For the foreseeable future, the assessment of odors in indoor environments will need to proceed as in the past, as a psychophysical measurement rather than as a chemical measurement. Methodologies for odor measurement continue to evolve. The evaluation of their usefulness in field settings must ultimately stand against a criterion of validity that has to date proved elusive to establish.