A new mechanism of ultrafine particle generation during concrete fracture

The production of dust during construction activities have a significant impact on the air quality of urban environments, particularly in the growing number of megacities in the world. While it is known that the fracture and crushing of concrete gives rise to large quantities of dust, it is not that well known that this process also produces ultrafine particles. Kumar et al (2012) observed that over 90% of the particles by number produced during concrete recycling activities were in the ultrafine size range. This is of concern as these small particles can penetrate deeper into the human lungs and therefore have a greater impact on health than coarser particles (Oberdorster et al., 2005). In this study, for the first time, we propose a new mechanism for the production of such ultrafine particles as a result of concrete fracture, based on evaporation and subsequent condensation of volatile chemicals at the fracture site.