Review Ultrafine Particles Emitted by Flame and Electric Arc Guns for Thermal Spraying of Metals

The ultrafine aerosol emitted by thermal spraying of metals using flame and electric arc pro-cesses has been characterized in terms of particle size distribution and emission rates based on both particle number andmass. Thermal spraying of Zn, Zn/Al, andAlwas studied.Measure-ments taken using an electrical low pressure impactor and a condensation nucleus counter reveal an aerosol made up of very fine particles (80–95 % of number distribution <100 nm). Ultrafine particle emission rates produced by the electric arc process are very high, the largest values being recorded during spraying of pure aluminium. This process generates high particle emissions and therefore requires careful consideration and possible rethinking of currently implemented pro-tection measures: ventilated cabins, dust collectors, and personal protective equipment