Upper-respiratory-tract symptoms (nasal irritation, congestion and rhinorrhea) are prevalent complaints in so-called "problem buildings." In epidemiologic studies, symptom reporting is associated with selected subject characteristics, including younger age, female gender, and the presence of allergic rhinitis. The physiologic correlates of these differential reporting patterns, however, are largely unknown. Using dilute chlorine gas as a model upper-respiratory-tract irritant, we studied 52 otherwise healthy volunteers in a sample stratified on age (18-69 yr), gender, and allergy status. In a single-blinded crossover study, subjects had their nasal airway resistance measured preexposure, immediately postexposure, and 15 min postexposure to both filtered air and chlorine (1.0 ppm in air) for 15 min. Allergic rhinitic subjects showed a significantly greater net (chlorine minus air) congestive response at 15 min postexposure than did nonrhinitic controls (p <.01). Advancing age also predicted a greater response immediately post-exposure (p <.01). No gender effect was observed. Significant interindividual variability was evident in the nasal congestive response to irritant (chlorine) provocation. The rhinitis effect was consistent with prior observations, whereas the effect of advancing age was opposite to that hypothesized.