Benzene is frequently used to extract collected bitumen fumes from personal sampler substrates. However, this solvent is particularly dangerous because of its carcinogenicity (group 1 of the International Agency for Research on Cancer classification). Therefore, to prevent the exposure of laboratory technicians to benzene during the fume extraction step from samplers, a compromise had to be found to identify a less toxic solvent with the same extraction capacity. To compare the extraction capacities of selected solvents, bitumen fumes were generated in the laboratory from three different batches of road surfacing bitumen collected on dedicated bitumen fume samplers. The samplers were then extracted by benzene and the solvents tested. Of 11 selected solvents less toxic than benzene and used in studies on bitumen and bitumen fume analyses, n-hexane and n-heptane were identified as alternatives to benzene. In particular, the results demonstrated that n-heptane was the best candidate solvent for benzene replacement, due to its extraction efficiency comparable to benzene for the three bitumen fumes tested and its low toxicity, which is highly compatible with benzene replacement.

Bitumen is classed as possibly carcinogenic to humans according to the International Agency for Research on Cancer. Data on individual exposure to bitumen fumes is therefore required to highlight the exposing situations and develop methods to prevent them. The Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) and the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS) have both developed methods to measure individual exposure. The objective of this study was to determine a conversion factor to allow interconversion of data acquired by the two methods. To develop this conversion factor, comparative laboratory and workplace tests were performed according to both the IFA method (No. 6305) and the INRS method (MetroPol M-2). The amounts of organic material collected on the filters and XAD-2 beds were compared. The results revealed differences between the sampling and analytical methods that could be linked to sampler design, extraction solvent, and the detection method used. The total quantification returned by the two methods-the sum of the masses quantified on filter and XAD-2 bed for each sampler-were correlated in both controlled and real-life tests. A conversion equation was therefore determined, based on field tests: CIFA = 1.76 CINRS ± 0.39 (R2 = 0.99) that is applicable to total quantification data. This formula can be applied to data acquired by the two institutes to increase the number of data points available on exposure to bitumen fumes in various conditions, and thus increase the statistical power of studies into occupational prevention.

Active sampling and analytical methods for the exposure assessment to chemical compounds have to be validated prior to be used on field. Requirements for the evaluation of these measuring procedures are specified in the ISO 22065 standard and include experiments to be done with a dynamic system for generating known concentration of gas and vapour in air under controlled conditions. Unfortunately, laboratories are rarely equipped with this kind of system and they have to carry out manual spiking of samples with a liquid micro-syringe, which is time consuming and source of uncertainty. In order to meet the requirements for accurate methods, we have designed and developed a fully automated generation system -called COMET generation system- that allows producing simultaneously four distinct concentration levels of gaseous pollutants and to perform automated multiple samples in each concentration branch according to the ISO 22065 standard compliance. The system is based on innovative pollutant generation, temperature and humidity control and multiple sampling technologies to be contained under a fume hood. The design of the system allows performing all the required sampling within a week whereas manual spiking need several weeks and excluding some important experiments where the temperature and the moisture have to be controlled. An online gas chromatograph or an Infrared photoacoustic analyzer determine the actual concentration in each concentration level branch. Two different methods were validated with both manual spiking and with the COMET system and the results were similar. Repeatability and overall uncertainty are significantly lower with the COMET system.

Exposure to organic vapors in the workplace is a source of occupational risk. Admissible exposure levels are tightly regulated and must be closely monitored. However, the complexity and slowness of the existing complete protocols to determine diffusive uptake rates through passive sampling have limited the use of this tool despite obvious advantages. In this study, we experimentally validate two simplified protocols to determine diffusive uptake rates with passive sampling. The proposed 2(6-3) and 2(6-2) fractional factorial designs were validated for toluene sampling using a (Gas Adsorbent Badge for Individual Exposure) GABIE-activated charcoal sampler in a controlled atmosphere. The uptake rate for this sampler had been determined previously using a full protocol. The uptake rates for all three protocols were similar, indicating that the proposed new designs can be substituted for classical full protocols. After validation of our protocols, uptake rates for new substances used as fuel additives (methyl and ethyl tert-butyl ethers, MTBE and ETBE) were determined on the same sampler using the 2(6-2) design. In these experiments, temperature appears to have a non-negligible influence on the uptake rates measured for these compounds. With some precautions of usage (ambient temperature below a determined limit temperature or at least exposure time ≥4 h) and storage (storage temperature = 4°C) of the sampler, the experimental diffusive uptake rates determined by this method can be used with good confidence. Field experiments confirmed the experimental results, showing good agreement between active and passive sampling using the experimentally determined uptake rates.

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.