Several environmental exposures of particular relevance for indoor air quality, such as exposure to odorants, may be associated with asthma and allergy. The aim of this study was to investigate attribution of symptoms and behavioral disruptions to various chemical and physical environmental sources in persons with self-reported asthma and allergy. Data from a population-based study, the Västerbotten Environmental Health Study, were used to compare persons with asthma, allergic rhinitis, allergic dermatitis, multiple diagnoses of asthma/allergy and no asthma or allergy. Persons with asthma and multiple diagnoses reported odorous/pungent and buildingrelated environmental factors to trigger symptoms to a larger extent than did the reference group, mainly due to perfume and odors from flowers. They also reported behavioral disruptions and affective reactions to odorous/ pungent environments. These findings increase the understanding of the role of odorants in symptom development and thereby the prevention of health problems in asthma and allergy in indoor air.