91 Isocyanates Aerosols Sampling for Occupational Exposures Assessment

Abstract

Abstract Isocyanate compounds are potent sensitizers, in particular through the development of skin dermatitis and allergies. They are one of the main causes of occupational asthma. None no-adverse-effect level has been establishes for isocyanates, therefore, it is important to measure isocyanates level at workplaces. Most of the time, isocyanates are present in workplaces atmosphere both in gas and particle phase, which makes their quantitative sampling difficult. Actual sampling methods do not fit with individual sampling over 8 hours. The aim of this work was first to characterize the particles size distribution in workplaces, depending on the isocyanate and the process used. Then, we studied the effectiveness of CIP 10-I as a sampling device for four isocyanates, compared to impinger and impregnated filter. Particles size distribution was determined thank to different cascade impactors such as Andersen, DLPI+ and MiniMOUDI-8. The Mass Median Aerodynamic Diameter (MMAD) of 4,4’-MDI (4,4’-diphenylmethane diisocyanate) particles in polyurethane foam projection process was found to be higher than 4 µm. In paint spray process, HDI (hexamethylene diisocyanate) particles MMAD was between 1 and 2 µm. The aerosol generation system was designed to obtain particles sizes closed to those observed in workplaces. The CIP 10-I collection foam was impregnated with the same derivative agent as filters. HDI, 2,4-TDI and 2,6-TDI (Toluene diisocyanate) aerosols were generating at concentrations between 10 and 250 µg/m3 in dry air. Whatever the concentration, CIP 10-I collection efficiency is higher than that of filters. Further investigation are currently performed to investigate CIP 10-I performance for MDI sampling.