Evidence of provincial variability in air pollutants-asthma relations in China

Abstract Exposure to air pollutants is a significant trigger of asthma in China. However, there is little evidence of which pollutants are associated most with asthma at the national level, and little research on pollutants' critical values based on concentration-response (C-R) curves. Further, the potential influential variables of air pollutants have not been identified clearly. In this study, logistic regression analyses were used to evaluate the associations between air pollutants and asthma based on 14176 samples across 12 provinces in China in 2015. We also fit a generalized additive model to evaluate the nonlinear C-R curves to identify the critical values. Our results showed that PM10-2.5 (odds ratios, 95% confidence intervals: 0.95, 0.90–1.00) and NOX (odds ratios, 95% confidence intervals: 0.98, 0.96–1.00) were associated significantly with asthma's prevalence (p