Short-term association between ambient air pollution and childhood non-allergic rhinitis: A time-series study at a National Children's Regional Medical Center, in Hefei, China, from 2015 to 2021

The relationship between air pollution exposure and non-allergic rhinitis (NAR) risk in children is underexplored and uncertain. Therefore, the impact of numerous air pollutants on the incidence of NAR in a Chinese pediatric population were investigated. Data on daily outpatient visits for NAR among children aged 0-18 years from 2015 to 2021 were obtained from Anhui Provincial Children's Hospital. A quasi-Poisson generalized linear regression model combined with a distributed lag nonlinear model was applied to evaluate the association between air pollution and outpatient visits for childhood NAR. A total of 38233 NAR outpatients were included and a positive association and cumulative effects between air pollution and childhood NAR were observed. The relative risks (RRs) and 95 % confidence intervals (95 % CIs) for childhood NAR at the 75th percentile of NO₂, SO₂, PM₁₀, PM_2.5, O₃, and CO against their minimum concentrations were 1.157 (95 % CI: 1.089, 1.23), 1.078 (1.005, 1.157), 1.168 (1.089, 1.252), 1.076 (1.02, 1.136), 1.033 (0.961, 1.11) and 1.07 (1.01, 1.134), respectively. The cumulative effects of the air pollutants were pronounced, which was much higher than each single effects. Furthermore, the risk estimates for childhood NAR during the cold season were higher than those in the warm season. Lastly, boys and school children were found to be more vulnerable to air pollutants than girls and preschool children. All these findings suggest that air pollutants have adverse effects on childhood NAR, even at levels below those recommended by the air quality guidelines. Our study results highlight the significance of paying attention to the effects of air pollutants to prevent NAR occurrence, particularly in boys and school children and during the cold season. Therefore, stronger control measures to mitigate air pollution must be implemented to decrease NAR incidence in the pediatric population.