Objective: There is limited evidence that atmospheric pollutants are associated with the number of allergic rhinitis (AR) visits. This study aimed to investigate the relationship between atmospheric pollutants and meteorological factors and the number of daily visits for AR in Hohhot City, providing a theoretical basis for further research on the effects of atmospheric pollutants on AR.
Methods: Microsoft Excel 2016 was used to collect and organize the AR outpatient consultation data, air pollution and meteorological data in Hohhot City during 2018– 2020, and the data were descriptively analyzed and Spearman correlation test was performed using SPSS22.0; A generalized additive model was built in R4.2.3 to analyze the effect of air pollution on the number of AR visits and its lagged and cumulative effects, while the robustness of the model was tested using a two-pollutant analysis. Finally, we analyzed the effects of the interaction of temperature, relative humidity and pollutants on the number of AR visits.
Results: The daily average concentrations of PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ in Hohhot during 2018– 2020 were 38.1 μg/m³, 83.3 μg/m³, 36.1 μg/m³, 15.1 μg/m³, 14.2 mg/m³, and 99.95 μg/m³, respectively, with the concentrations of PM_2.5 and PM₁₀ exceeding the secondary limit of the national standard. The results of the generalized additive model analysis showed that the RR and 95% CI of the effect of each 10 μg/m³ increase in pollutant concentration (1 mg/m³ increase in CO) on the number of AR outpatient clinics were 1.008 (1.001– 1.016), 1.002 (1– 1.005), 1.072 (1.033– 1.113), 1.020 (1007– 1.034), 1.033 (1.014– 1.052), 0.987 (0.9804– 0.9936).
Conclusion: Short-term exposure to PM_2.5, PM₁₀, SO₂, NO₂, and CO was significantly associated with an increase in AR clinic visits, and short-term exposure to O₃ was significantly associated with a decrease in allergic rhinitis clinic visits.
Keywords: allergic rhinitis, air pollutants, time series study, interaction effect