Objective To explore the relationship between the outpatient visits for adult asthma and air pollution in a tertiary hospital in Hefei. Methods The number of outpatient visits for asthma in a tertiary hospital in Hefei from 2014 to 2020 was collected. The air pollutant data was obtained through the Hefei Air Monitoring Station, and the meteorological indicators of the same period were collected through the China Meteorological Network. The R statistical software was used to establish a generalized additive model to analyze the lag effect of air pollution on the number of outpatient visits for asthma. Results From 2014 to 2020, there were 7 220 asthma outpatients in the tertiary hospital in Hefei, including 3104 males and 4 116 females, 3 798 patients in warm season, and 3 422 patients in cold season. During the period, the average concentrations of SO₂, NO₂, CO, O₃, PM₁₀, and PM_2.5 were 11.9μg/m³, 40.1μg/m³, 0.9 mg/m³, 87.3μg/m³, 81.3μg/m³, and 55.7μg/m³, respectively. The results of the single-pollutant model showed that every 10μg/m³ increase in SO₂ concentration increased the risk of asthma by 0.74% (95%CI: 0.22%-1.29%), and the effect was the greatest on Lag2 day. NO2 increased the risk of asthma by 0.31% (95%CI: 0.13%-0.49%), with the greatest effect on Lag0 day. The analysis of the dual pollutant model found that whereas the effect of SO₂ decreased after the incorporation of NO₂, the effect increased after the incorporation of CO, O₃, PM₁₀, or PM_2.5, respectively. The effect of NO₂ on asthma decreased after the incorporation of SO₂, whereas the effect on asthma increased after the inclusion of CO, PM₁₀, or PM_2.5. Stratified analysis of cold and warm seasons showed that the effect of NO₂ on asthma was the greatest in lag0 in cold season. The effect of SO₂ was higher in cold season than in warm season, and it was the highest in lag2. The gender stratification analysis showed that the effects of SO₂ and NO₂ on male asthma were higher than those on females. Conclusion From 2014 to 2020, the increase of SO₂ and NO₂ concentrations in Hefei is positively correlated with the risk of asthma in the outpatient department of a tertiary hospital. The effect has a certain lag. It is of great significance to formulate relevant preventive measures for the occurrence and attack of asthma.