Intense generation of respirable metal nanoparticles from a low-power soldering unit

•Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected.•Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30min after operation.•Nanoparticle concentration in the working environment depends on the presence of ambient air.•Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. Evidence of intense nanoparticle generation from a low power (45W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 106 particles/cm3) within the breathing range of the operator, with initial size distributions centered at 35–60nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals.