Introduction Although the impact of air pollutants on infectious diseases is well-known, there is limited evidence regarding its effects on peritoneal dialysis (PD) patients. This study aimed to investigate the association between air pollutants and PD-related peritonitis. Methods This is an observational study affiliated to the PD Telemedicine-assisted Platform Cohort Study (PDTAP study), which is a national-level cohort study in China. The primary outcome was PD-related peritonitis, and the secondary outcomes were peritonitis-related death and transfer to hemodialysis. The pollution data were obtained from China High Air Pollutants according to the patients' place of residence. The association between pollutants and outcomes was evaluated by cause-specific Cox proportional hazard regression model. The patients were divided into the high-pollution group and low-pollution group according to the median value of PM2.5 (53.90 mu g/m(3)) and the WHO standard of PM2.5 (35.00 mu g/m(3)). Results A total of 7439 PD patients from all 7 geographical regions across China were enrolled between June 2016 and April 2019. There were 1585 patients who developed peritonitis during follow-up. The pollution was most severe in the north and central regions of China. Patients in the high-pollution group were characterized by older age, higher BMI, lower income, from rural and non-university affiliated hospitals, and had more comorbidities and better residual renal function. In multivariate analysis, PM2.5 and its components (SO4, NO3, NH4, OM, and BC), PM10, NO2, and CO were associated with increased peritonitis risk (P < 0.001-0.027). Additionally, following the propensity score matching to control for key individual-level covariates, the association between PM2.5 and its components, NO2, and CO with elevated peritonitis risk remained significant (P < 0.001). Conclusion In this national large-scale Chinese PD cohort study, air pollutants were found to be associated with increased risk for peritonitis.