Particle size distributions and health-related exposures of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) of sinter plant workers

This study measured particle size distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in two workplace atmospheres of the sintering grate and rough roll shredder in a sintering plant, and to assess their workers' health-related exposures. We found that the PCDD/F concentration of the sintering grate (site A = 14.47 pg m^-3) was lower than that of the rough roll shredder (site B = 17.20 pg m^-3). Particle size distributions of PCDD/Fs were in the form of the unimodal with the mass median aerodynamic diameter (MMAD) of 4.74 μm and 5.23 μm, and geometric standard deviation (σ_g) of 3.15 and 2.15 for the site A and B, respectively. The above results suggest that the workplace of the site A had a less fraction of coarse particles than that of the site B. The estimated PCDD/F concentrations of the inhalable fraction (11.0 pg m^-3) and thoracic fraction (8.89 pg m^-3) of the site A were lower than those of the site B (12.4 and 9.39 pg m^-3, respectively). But to the contrary the estimated respirable fraction of the site A (5.05 pg m^-3) was slightly higher than that of the site B (4.93 pg m^-3). Our results clearly indicate the importance to conduct particle size segregating samplings for assessing human PCDD/F exposures.