BACKGROUND: The influence of air pollution on osteoarthritis (OA) remains underexplored. METHODS: We conducted a prospective cohort study in the UK Biobank, estimating exposure levels of particulate matter (PM RESULTS: Individual exposure to each air pollutant was associated with an increased risk of developing OA, but not with progression from OA to joint replacement. For APES, the hazard ratio for incident OA was 1.09 (95 % CI = 1.04-1.13), and the hazard ratio of progression from OA to death was 1.16 (95 % CI = 1.00-1.35) in the highest quartile group compared to the lowest quartile group. Moreover, genetically predicted methylation at the PM CONCLUSION: Long-term exposure to air pollution was associated with an increased risk of OA in the population and poorer survival outcomes for OA patients, with epigenetic changes in GDF5 potentially playing a role in the underlying mechanisms.