There is a paucity of symptom data reported in controlled human exposure studies. This study examined symptom responses and subjective evaluation of perceived pollution through self and researcher-administered questionnaires in 10 asthmatics and 10 non-asthmatics, exposed for 2-hours to filtered air, low (∼66mug/m3) and high (∼136mug/m3) CAP with/without O 3 (120ppb). Symptom and exposure severity responses were not significantly different between asthmatics and non-asthmatics. However, when respiratory symptoms were grouped together in a cluster, a trend emerged with asthmatics reporting more symptoms than non-asthmatics. Analysis of variance and tests for marginal homogeneity showed mostly non-significant differences for symptoms or severity rating for CAP, O3 and their interaction effects. Participants reported more symptoms for the researcher- versus self-administered questionnaire. Those who perceived exposure to pollutant(s) tended to report more symptoms and higher exposure severity. This data suggests a relationship between subjective perception of pollutant(s) exposure and symptom reporting that merits further study.