Chemical speciation of size-segregated floor dusts and airborne magnetic particles collected at underground subway stations in Seoul, Korea

► We examined chemical species of floor dusts and airborne magnetic subway particles collected at underground subway stations. ► XRD, SEM/EDX, and VSM measurements provided information on their major iron species, which is relatively harmless iron metal. ► PM levels at underground subway stations can be controlled by removing magnetic indoor particles using magnets.