Agarose gel electrophoretic pattern of DNA with single strand breaks (SSBs) induced by supernatant containing only mobilized metals from urban particulate matter (PM). Experimental details are described in Materials and Methods section (I: form I DNA, i.e. DNA with SSB; II: form II DNA, i.e. closed-circular, superhelical DNA). (a) Lane 1, untreated control DNA; lane 2, DNA + EDTA; lane 3, DNA + ascorbate; lane 4, DNA + SRM1648; lane 5, DNA + EDTA + ascorbate; lane 6, DNA + SRM1648 + citrate; lane 7, DNA + SRM1648 + citrate + ascorbate; lane 8, DNA + SRM1648 + EDTA; lane 9, DNA + SRM1648 + EDTA + ascorbate; and lane 10, DNA + SRM1648 + EDTA + ascorbate + desferrioxamine (DFO). (b) Lane 1, DNA + PM2.5; lane 2, DNA + PM2.5 + EDTA; lane 3, DNA + PM2.5 + EDTA + ascorbate; lane 4, DNA + PM2.5 + EDTA + ascorbate + DFO; lane 5, DNA + PM10; lane 6, DNA + PM10 + EDTA; lane 7, DNA + PM10 + EDTA + ascorbate; and lane 8, DNA + PM10 + EDTA + ascorbate + DFO.