Ultrafine Aerosols in the Workplace

Abstract

Following a review of industries based in the UK, it was found that not many are involved in the use or handling of ultrafine powders, or are involved in processes which may produce ultrafine particles, or particles with high specific surface areas. A limited set of measurements of particle number concentration and size distribution was carried out in those industries where ultrafine particles were likely to be found. The findings were as follows: (i) There was no evidence that ultrafine powders or particles are aerosolized in an unagglomerated state, or remain so for a significant length of time during any of the processes investigated; (ii) the industrial processes investigated involving heat, such as welding, soldering and plasma spraying, produced high levels of aerosol in the ultrafine size region; (iii) the concentration and size distribution of ultrafine particles inside the factory could, at times, be dominated by levels in the ambient air outside the factory, where particles from local combustion sources such as vehicles and oil refineries emit massive numbers of ultrafine particles.