The present study is the first report of the oxidative potential (OP) of atmospheric PM10 over marine environments. PM10 samples were collected onboard the Fishery Oceanographic Research Vessel Sagar Sampada (SS#359) over the Arabian Sea during April–May, 2017 and analyzed for a variety of chemical species and OPs. The PM10 mass concentration, volume-normalized OP [represented as nmol dithiothreitol (DTT) min–1 m–3 or OPV], and mass-normalized OP (represented as pmol DTT min–1 μg–1 or OPM) over the study region varied from 61 to 184 μg m–3, 0.69 to 2.08 nmol DTT min–1 m–3, and 6 to 26 pmol DTT min–1 μg–1, respectively. The study period was classified into two categories (Class-A and Class-B) based on 5-day air mass back trajectories for each sampling location. The mass fraction of mineral dust was ∼2.5 times higher in Class-B samples (representing the Arabian Desert/marine air masses) in comparison with Class-A samples (representing the continental air mass). The average OPV and OPM associated with Class-...