Human exposure to ambient metallic nanoparticles is an area of great interest. Ambient metallic nanoparticles found in the roadside environment are contributed by combustion engines and wear of brakes, tyres and road surfaces. However, it is not yet fully understood to what extent ambient metallic nanoparticles can cause health problems. A detailed quantitative analysis of atmospheric nanoparticles is therefore needed. This paper aims to present comprehensive physical and chemical characterisation data for submicron atmospheric iron particles collected at two UK urban sites.