Despite the large prevalence in the population, possible factors responsible for the induction of atrial fibrillation (AF) events in susceptible individuals remain incompletely understood. We investigated the association between air pollution levels and emergency department admissions for AF in Rome. We conducted a 14 years' time-series study to evaluate the association between the daily levels of air pollution (particulate matter, PM10 and PM2.5, and nitrogen dioxide, NO₂) and the daily count of emergency accesses for AF (ICD-9 code: 427.31). We applied an over-dispersed conditional Poisson model to analyze the associations at different lags after controlling for time, influenza epidemics, holiday periods, temperature, and relative humidity. Additionally, we evaluated bi-pollutant models by including the other pollutant and the influence of several effect modifiers such as personal characteristics and pre-existing medical conditions. In the period of study, 79,892 individuals were admitted to the emergency departments of Rome hospitals because of AF (on average, 15.6 patients per day: min = 1, max = 36). Air pollution levels were associated with increased AF emergency visits within 24 h of exposure. Effect estimates ranged between 1.4% (0.7-2.3) for a 10 µg/m³ increase of PM10 to 3% (1.4-4.7) for a 10 µg/m³ increase of PM2.5 at lag 0-1 day. Those effects were higher in patients ≥75 years for all pollutants, male patients for PM10, and female patients for NO₂. The presence of previous cardiovascular conditions, but not other effect modifiers, increase the pollution effects by 5-8% depending on the lag. This study found evidence that air pollution is associated with AF emergency visits in the short term.