BackgroundOutdoor air pollution, including ozone (O3) pollution, and childhood family environments may interact and impact asthma exacerbations in children. Previous epidemiology studies have primarily focused on stress in the home, rather than support, and whether psychosocial factors modify the association between pollution and health outcomes, rather than whether pollution exposure modifies associations between psychosocial factors and health outcomes.MethodsData from the cross-sectional 2003 representative, population-based California Health Interview Survey were linked with air quality monitoring data on O3pollution from the California Air Resources Board. Adolescents (N= 209) ages 12–17 who reported an asthma diagnosis and lived within 5 mi of the nearest air monitoring station had linked O3data for a 12-month period preceding the survey interview date. Adolescents reported perceived available support from an adult at home and frequency of asthma symptoms.ResultsIn unadjusted models, for adolescents living in high O3pollution regions, greater perceived support was related to lower asthma symptom frequency. Follow-up analyses suggested that the most plausible interpretation of the interaction was that O3exposure modified the association between perceived support and symptom frequency. O3× perceived support interactions were not statistically significant after adjusting for covariates.ConclusionsThese data provide preliminary evidence that the association between the lack of support in the home environment and worse asthma symptoms may be stronger in areas with higher O3exposure. Future work may benefit from incorporating personal pollution exposure assessments, comprehensive family environment assessments, and longitudinal follow-up of asthma exacerbations over time.