Highlights:1. Indoor size-segregated particles were collected at the Hutou lung cancer epidemic village.2. DNA damage assessed by plasmid scission assay was mainly caused by smaller particles.3. DNA damage had a positive correlation with the water-soluble Zn, Cu, Cd, Rb, Cs, and Sb. 4. Water-soluble metals Zn, Cu, Cd, Rb, Cs, and Sb were concentrated in the smaller particles.5. Indoor particles in the small sizes were a higher health risk than those in the large sizes.