The association between air pollution, allergic rhinitis (AR), and obesity has not been studied. From 2007 to 2011, 52 obese and 152 non-obese children (7-17 years old) with AR were recruited. Pediatric-Rhinoconjunctivitis-Quality-of-Life Questionnaire (PRQLQ) and nasal peak expiratory flow (NPEF) were tested. Association between the scores and rates of the two tests and mean air pollutant concentrations within 7 days before the tests were compared. When exposed to higher concentrations of CO, PM, and PM, the rates of worse nasal discomfort were 39.4%, 44.4% and 39.3% in obese children; and 18.0%, 21.9% and 19.7% in non-obese children, respectively. Compare to non-obese children, the rates in obese children were higher for CO (odds ratio (OR) 3.54, 95% confidence interval (CI) 1.15 ~ 10.92); PM (OR 3.26, 95% CI 1.01 ~ 10.57) and PM2.5 (OR 3.30; 95% CI 1.03 ~ 10.54). In obese children, correlations between higher concentrations of CO, PM, PM and higher nasal discomfort (higher PRQLQ); and correlations between higher concentrations of CO, PM, PM, NMHC (non-methane hydrocarbon) and higher nasal mucosa inflammation (lower NPEF) were noted. Obesity negatively affected AR severity when AR children experienced higher concentrations of CO, PM, and PM. Increased nasal inflammation induced by air pollutants might be the underlying mechanism.© 2023. The Author(s).