RETRACTION: Association between air pollutants, sources, and components of PM2.5 and pediatric outpatient visits for respiratory diseases in Shanghai, China (Retraction of Vol 126, Pg 476, 2019)

Background: Although exposure to ambient air pollution has been associated with outpatient visits for respiratory diseases, there have been few recent studies investigating the effect of the chemical components of ambient particulate matter with an aerodynamic diameter of <2.5 mu m (PM2.5) on pediatric outpatient visits for respiratory diseases. In addition, there remains scarce evidence regarding PM2.5 components and sources that are most relevant to pediatric outpatient visits for respiratory diseases. This study aimed to determine the association between four ambient pollutants (SO2, NO2, PM10, and PM2.5), sources and chemical components of PM2.5, and pediatric outpatient visits for respiratory diseases.Methods: This time-series study was conducted between January 1, 2018 and December 31, 2019 in Shanghai, China. A positive matrix factorization model was used to determine the source apportionment of PM2.5, and a generalized additive model was employed to evaluate the effect of air pollutants and the components and sources of PM2.5 on pediatric outpatient visits for respiratory diseases. In addition, a two-pollutant model was used to investigate the potential confounding effects of the copollutants.Results: The study revealed that a 10 mu g/m(3) increase in SO2, NO2, PM10, and PM2.5 concentrations corresponded to increases of 3.4% (95% CI: 2.3%-4.6%), 1.9% (95% CI: 1.7%-2.2%), 0.5% (95% CI: 0.4%-0.7%), and 0.5% (95% CI: 0.4%-0.7%), respectively, in pediatric outpatient visits for respiratory diseases on the day with the most significant lag effect. Notably, Ni exposure more strongly correlated with increased pediatric outpatient visits for respiratory diseases, with the percent of increase by 10 ng/m(3) ranging from 7.6% to 16.5%. Moreover, among the PM2.5 sources researched in this study, oil and coal combustion were the most important for increasing pediatric outpatient visits for respiratory diseases.Conclusion: This study demonstrates that ambient pollutants and the chemical components and sources of PM2.5 were significantly associated with an elevated risk of pediatric outpatient visits for respiratory diseases and provides insights into the differential health risks of PM2.5 components.