Ultrafine particle characteristics in a rubber manufacturing factory

Background: According to epidemiological research, exposure to rubber fumes can cause various types of cancer and can lead to an increase in death rate because of cardiovascular diseases.Objectives: In this study, we have assessed the characteristics of ultrafine particles emitted into the air during the manufacturing of rubber products using waste tires.Methods: To assess the aerosol distribution of rubber fumes in the workplace from a product during curing, we have performed particle number concentration mapping using a handheld condensation particle counter.The particle number concentration of each process, count median diameter (CMD), and nanoparticle ratio (<100nm) were determined using an electrical low-pressure impactor (ELPI), and the surface area concentration was determined using a surface area monitor. The shape and composition of the sampled rubber fumes were analyzed using an ELPI-transmission electron microscopy grid method. Further, the rubber fume mass concentration was determined according to the Methods for the Determination of Hazardous Substances 47/2.Results: The results of particle mapping show that the rubber fumes were distributed throughout the air of the workplace. The concentration was the highest during the final process of the work. The particle number concentration and the surface area concentration were 545 000cm^-3 and 640 m² cm^-3, respectively, approximately 10-and 4-fold higher than those in the outdoor background.During the final process, the CMD and the nanoparticle ratio were 26nm and 94%, respectively. Most of the rubber fume particles had a compact shape because of the coagulation between particles. The main components of these fumes were silicon and sulfur, and heavy metals such as zinc were detected in certain particles. The filter concentration of the rubber fumes was 0.22mg m^-3, lower than the UK workplace exposure limit of 0.6mg m^-3.Conclusions: Therefore, the rubber manufacturing process is a potentially dangerous process that produces a high concentration of specific nanoparticles.