Aerosols are a source of dissolved iron (d-Fe) to the ocean. However, the factors controlling Fe solubility, which is closely linked to bioavailability, remain poorly understood. Using total and dissolved iron and aluminum datasets, this study estimated Fe solubility in mineral dust and anthropogenic particles. The results show that the inverse relationship between Fe_sol% and Fe concentration is primarily driven by progressive solubilization of mineral dust Fe during atmospheric transport.