[Effects of Air Pollutants on Outpatient Visits for Atopic Dermatitis in Lanzhou]

Objective To quantitatively evaluate the associations of PM_2.5,PM₁₀,NO₂,and SO₂ concentrations with the outpatient visits for atopic dermatitis in Lanzhou. Methods The data of outpatient visits,together with meteorological data and air pollutant data,from January 2013 to December 2017 were collected.The generalized additive model based on Poisson distribution was employed to study the lag effects of PM_2.5,PM₁₀,NO₂,and SO₂ concentrations on the visits of outpatients,with the seasonal and long-term trends and day-of-the-week effect controlled. Results The results of the single pollutant model showed that PM_2.5 and PM₁₀ had the most obvious while still insignificant impact on the outpatient visits for atopic dermatitis on the current day(lag0).NO₂ also had the most obvious impact in the case of lag0 and showed a lag effect.For each 10 μg/m³ increase in NO₂ concentration,the excess risk(ER)of outpatient visits for atopic dermatitis was 1.95%(95% CI=1.09%-2.82%,P=0.01).SO₂ had the most significant effect on lag6,and the outpatient visits increased by 1.55%(95% CI=0.48%-2.54%)for every 10 μg/m³ rise in SO₂ concentration(P=0.02).Females were more sensitive to PM₁₀ and SO₂ than males.For every 10 μg/m³ increase in PM₁₀ and SO₂,the female outpatient visits increased by 0.02% and 2.47%,respectively.Males were sensitive to PM_2.5 and NO₂,and the every 10 μg/m³ rise in PM_2.5 and NO₂ increased male outpatient visits by 0.47% and 1.78%,respectively.Gaseous pollutants(NO₂ and SO₂)had more significant effect on people ≤2 years old than on those of other ages.Every 10 μg/m³ rise in NO₂ and SO₂ would increase the ≤2-year-old outpatient visits by 2.35% and 1.57%,respectively(P=0.02).People of 13-59 years old were sensitive to NO₂ concentration,and every 10 μg/m³ rise in NO₂ concentration increased their visits by 1.39%.NO₂ affected the outpatient visits during the cold and warm seasons,with the ER values of 2.35% and 1.89%,respectively(P=0.01).Particulate matter(PM_2.5 and PM₁₀)had the most obvious yet insignificant association with the outpatient visits in winter.The interactions between PM_2.5 and NO₂,between PM₁₀ and NO₂,and between SO₂ and NO₂ affected the total outpatient visits for atopic dermatitis.The results of double pollutant model showed that in the presence of PM_2.5,PM₁₀,or SO₂,the effect of NO₂ on the outpatient visits for atopic dermatitis enhanced compared with that predicted by single pollutant model(P=0.01). Conclusion The air pollutants(PM_2.5,PM₁₀,NO₂,and SO₂)in Lanzhou were closely related to the outpatient visits for atopic dermatitis,and the increased concentrations of NO₂ and SO₂ was more likely to increase the risk of atopic dermatitis.