Abstract Body (Do not enter title and authors here): Background:
Fine particulate matter (PM2.5) is increasingly recognized as a cardiovascular risk factor, with both short- and long-term exposure associated with higher rates of atrial fibrillation (Afib). However, few studies have assessed its relationship with Afib using comprehensive burden metrics such as disability-adjusted life years (DALYs) at the population level.

Aim:
To evaluate the association between long-term PM2.5 exposure and the burden of Afib, measured in DALYs, across U.S. states from 2000 to 2021.

Methods:
We conducted a longitudinal ecological analysis using state-level data from the Global Burden of Disease (GBD) study and the U.S. Environmental Protection Agency (EPA). Afib-related DALYs, deaths, and prevalence were age-standardized and sex-combined. Annual PM2.5 concentrations were averaged across the study period. Covariates included summary exposure values for obesity, smoking, hypertension, high fasting plasma glucose, high LDL cholesterol, and kidney dysfunction. Multivariable linear regression assessed the independent association between PM2.5 and Afib DALYs, adjusted for all covariates. Interaction terms between PM2.5 and both obesity and smoking were tested in secondary models. Choropleth maps and trend plots were used to visualize spatial and temporal patterns.

Results:
Afib DALY rates varied across states, with the largest increase in California (+46%) and the largest decrease in Pennsylvania (–5%). Higher long-term PM2.5 exposure was independently associated with increased Afib DALY rates (β = 1.21, p < 0.0001; 95% CI: 0.89–1.53). PM2.5 was also associated with Afib prevalence (β = 13.47, p < 0.0001), but not with deaths (β = 0.011, p = 0.16). No significant interactions were observed with obesity or smoking. While PM2.5 declined nationally, Afib burden increased or plateaued in most states.

Conclusions:
Ambient air pollution is independently associated with Afib burden and prevalence across U.S. states, even after adjustment for cardiometabolic and renal risk factors. These findings align with recent international research linking PM2.5 to increased Afib incidence and provide new evidence of its contribution to population-level disease burden in the U.S. This highlights air quality as a potential modifiable contributor to the growing Afib epidemic and underscores the importance of environmental health policy in arrhythmia prevention.