Abstract The CIP 10 is a personal aerosol sampler designed to sample conventional dust or specific occupational inorganic or organic substances such as crystalline silica, isocyanates or mycotoxins. It is widespread used, especially in France. Within the CIP10, the rotating cup contains a porous polyurethane foam devoted to the collection of airborne particles and rotates inside its housing at a speed close to 6700 rpm to induce a 7 or 10 L/min sampling airflow, depending on the particle-size selector. Despite several published works regarding its physical performances, no experimental data exist regarding the sampling efficiency for submicron particles. This study aimed to measure the collection efficiency of the CIP 10 for different types of foam (60 or 75 ppi, functionalized or not) and for the three selectors (inhalable, thoracic, respirable). Polydisperse particles with aerodynamic diameters between 20 nm and 10 µm were produced using various generators and different materials (DEHS, glass beads) in a specific test rig. For a given diameter, the collection efficiency was calculated by comparing the number concentrations measured alternatively upstream and downstream of the rotating cup, using APS (TSI 3321) or SMPS (Grimm DMA Vienna Type, CPC 5.403) spectrometers. While collection efficiency was 100% for particles > 3 µm, it progressively decreased to around 50 % and even below 10 % for aerodynamic diameters of 800 mm and 150 nm, respectively. Collection efficiency was unaffected by the type of foam or sampler flow rate used. Bias maps and consequences on workers aerosol exposure assessment will be discussed.

Abstract Assessing occupational inhalation exposure to airborne nano-objects, their agglomerates and aggregates (NOAA) is a challenge due to the multiple possibilities to measure them in the absence of regulation. The size range of NOAA is very wide, from sub-100 nm nanoparticles to micron-sized agglomerates and aggregates. Consequently, a suite of middle to high costs direct-reading instruments are commonly used to determine airborne NOAA concentrations in workplaces. Due to the high cost of such devices, measurements with high spatial resolution are not feasible. New Low-Cost Sensors (LCS) have emerged since the last ten years, providing a high degree of compactness, a high time resolution and a reduced price (<200 €). Consequently, these sensors offer new possibilities to assess workers’ exposure during their activity. Since these sensors are typically calibrated for the measurement of ambient PM concentrations, their use in workplaces may be limited due to different particle properties or when faced with medium to high occupational mass concentrations. In order to study the applicability of LCS for NOAA dust concentration measurements in workplaces, a pre-normative research project has been initiated. Six different sensor types have been tested, namely Plantower PMS 7003, Nova Fitness SDS011, Alphasense OPC-R1, Sensirion SPS30 and Groupe Tera Next PM and Next PM-CR. 9 NOAA powders were involved to produce the test aerosols in a low-speed wind tunnel. The results show that sensors output vary strongly with the powder’s nature. In addition, the PM fractions from the LCS are correlated to the PM fractions measured by the reference method.

Semi-volatile organic compounds (SVOCs) are airborne pollutants present as a mixture of airborne particles and their vapour. Evaluating the exposure of workers to SVOCs represents a major challenge to occupational hygienists due to different toxicological effects regarding the particles and the vapour phases on human health. Therefore, the exposure assessment requires sampling these phases separately. In this regard, several methods were proposed to separate the two phases. However, all these methods have biased measurements of the concentration of the particulate and vapour phases. As an alternative, we propose a new personal SVOCs sampler named PPAS for “Préleveur Personnel d’Aérosols Semi-volatils”. The PPAS was built on the virtual impactor concept but with an inverted ratio between the major and minor flow. The development of the PPAS was first carried out using computational fluid dynamics (CFD) and then using experiments to estimate the actual performances. A great attention was paid to reduce at their minimum the pressure drops between the inlet and the two exits to allow 8 hours samplings using personal pumps classically used for assessing the exposure of the workers in workplaces. The transmission efficiency η of the PPAS was evaluated by CFD calculations for particles size ranging between 0.05 and 20 µm and measured experimentally with mono-dispersed aerosols consisted of a mixture of glycerol and fluorescein particles of 0.15, 2, 3 and 4.5 µm. The aim of the presentation is to focus on the CFD and experimental tests that permit to develop the PPAS.

Dichotomous sampling of a mixture of gas and aerosol is looked for in many applications such as airborne SVOC (semivolatile organic compound) sampling. This article revisits the computational fluid dynamics simulation of the original SVOC aerosol dichotomous sampler (Kim & Raynor, 2009) to investigate which among some factors influence most the representativeness of such simulations. Considered modeling factors of influence are the 2D-axisymmetric reduction of space and the choice of turbulence model (realizable k-e vs. k-o BSL or k-o SST). Considered physical factors of influence are the particles aerodynamic diameter (range 50 nm to 20 mu m), the type of inlet condition for gas and particles (uniform or free-sampling condition), the particles turbulent dispersion and the particles initial radial position at inlet. Results are supported by an extensive numerical verification procedure and by available validation data. In this specific confined transitional two-phase flow, it is found that the axisymmetric simplification holds, that the tur-bulence model affects significantly the predicted flow pattern but less pressure drops and marginally the fate of aerosol particles. Turbulent dispersion of aerosols is found negligible, but the effect of inlet boundary condition appears decisive on aerosol motion despite a marginal influence on the flow pattern. In particular, for aerodynamic diameters above 2 mu m, free-sampling conditions produce a strong focusing effect of particles which drastically helps in limiting wall deposition. These findings highlight particularly the importance of using a physically sound inlet condition for aerosol particles when simulating aerosol samplers, rejecting the usual simplistic uniform condition. Results also particularly emphasize the necessity of a thorough verification procedure for the computation of both phases when using CFD for similar samplers. Regarding the application to dichotomous sampling, it appears that any process that moves particles away from the wall upon entry improves the separation efficiency of the device while decreasing deposition.

SemiVolatile Organic Compounds (SVOCs) are present simultaneously in two phases, the particulate phase (liquid or solid) and the vapour phase. Several toxicological studies have shown different health effects between the two phases, as they are collected by different mechanisms and at different locations in the respiratory tract. Consequently, the evaluation of the SVOCs workers’ exposure at workplace requires to measure separately the particles and the vapour concentrations, in order to better assess the risks to their health. In this paper, we present a performance study on the Semivolatiles Aerosol Dichotomous Sampler (SADS) proposed by Kim and Raynor (2009). This study was conducted using experimental tests and numerical simulations. Experimental tests on SADS were performed with monodispersed droplets of glycerol seeded with fluorescein having diameters of 0.15, 2, 3 and 4.5 µm. Validated numerical simulations were used to calculate the transmission efficiency that was compared to the experimental data. The main experimental observation was as an important particles deposition inside the SADS up to 40 %, that was not predicted by numerical simulations. Comparisons between the numerical simulations and experimental data highlighted some factors that reduced the transmission efficiency of the particle phase through the SADS, such as the misalignment of the SADS nozzle, the assembling repeatability and the lack airtightness. Acting on these factors would make it possible to design a more efficient device in future studies.

Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08-0.1 ng/cm(2)/h) compared to without (0.02-0.26 ng/cm(2)/h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97-13.01 ng/cm(2)/h) compared to with UV-S (0.40-6.35 ng/cm(2)/h). Time until permeation (Tiags) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV.

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.

A laboratory system was designed to generate bitumen fumes and expose tested samplers in a homogenised chamber. The system was also designed to condense the fumes in the form of oil that could be used as a standard for further analytical method development. The laboratory system was evaluated in terms of stability, repeatability, aging, and ranges, focusing on the quality and quantity of the fumes and their physical characteristics. The fumes generated with the laboratory system were also compared to fumes emitted at workplaces to evaluate their similarity. The results demonstrated that laboratory fume generation was stable and repeatable. Humidity ranged from 20% to 80% RH and the total fume concentration ranged from 0.01 to 9.36 mg.m-3, covering the conditions encountered for road paving worksites. The fumes generated in the laboratory were found to be similar to those of workplaces, with slight differences in light compounds equivalent to C12 and below n-alkanes. Thus, the system designed in this study is considered capable of generating bitumen fumes used to develop sampling and analysis methods.

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.

Les filtres a fibres sont communement utilises pour diminuer la concentration des aerosols liquides sur les lieux de travail et pour controler leurs concentrations. Cependant, l'efficacite de ces filtres est remis en question par la capacite de ces aerosols deposes a s'evaporer lorsque de l'air non sature passe au travers. La comprehension du phenomene lie a l'evaporation d'aerosols liquides semi-volatils est donc necessaire pour predire la perte d'une masse d'aerosol. Cette etude presente une nouvelle approche pour la comprehension du comportement de l'evaporation en faisant des observations de gouttes deposees sur des fibres a l'echelle microscopique. Les observations ont montre que la cinetique d'evaporation n'est pas correlee aux lois de Fick, comme attendu. Il existe quelques elements prouvant que la cinetique d'evaporation est conditionnee par le diametre initial des gouttes au moment de leur collecte sur les fibres.

The ultrafine aerosol emitted by thermal spraying of metals using flame and electric arc processes has been characterized in terms of particle size distribution and emission rates based on both particle number and mass. Thermal spraying of Zn, Zn/Al, and Al was studied. Measurements taken using an electrical low pressure impactor and a condensation nucleus counter reveal an aerosol made up of very fine particles (80-95% of number distribution <100 nm). Ultrafine particle emission rates produced by the electric arc process are very high, the largest values being recorded during spraying of pure aluminium. This process generates high particle emissions and therefore requires careful consideration and possible rethinking of currently implemented protection measures: ventilated cabins, dust collectors, and personal protective equipment.

De nombreuses sources d'aerosols liquides (fluides de coupes, pesticides,...) sont presentes dans les atmospheres industrielles. Pour controler ou pour diminuer l'exposition des salaries a ces aerosols potentiellement toxiques, il est necessaire de les filtrer sur des medias fibreux. Cependant, lorsqu'un air non sature en vapeurs traverse un filtre colmate, une perte par evaporation des gouttes deposees sur les fibres peut se produire. Par voie de consequence, les salaries se retrouvent etre exposes a des vapeurs plus concentrees par rapport a l'etat initial de l'aerosol filtre et les mesures de controle d'exposition (concerne les preleveurs ) sont entachees d'une erreur qui peut etre importante. Cette etude a pour objectif de fournir un ensemble de donnees experimentales, la litterature etant assez pauvre dans ce domaine, afin d'identifier et de comprendre les phenomenes preponderants dans l'evaporation d'un aerosol liquide semi-volatil collecte sur un filtre a fibres, de composition pure ou non, pour au final pouvoir ameliorer les quelques modeles theoriques de la litterature.

Numerous sources of liquid aerosols are to be found in industrial environments. Such aerosols may, for instance, be cutting fluids, pesticides, etc., that are harmful or even toxic to humans. To control and reduce worker exposure to potentially toxic aerosols, these latter are usually filtered through fibrous filters. When non-saturated air traverses a clogged filter, however, the drops deposited on the fibers may evaporate. Consequently, workers are exposed to greater amounts of more concentrated vapors than the initial state of the filtered aerosol. Furthermore, exposure readings are distorted by an artifact that may be significant. This study offers an experimental approach to long-term monitoring of the evaporation of a semi-volatile n-hexadecane liquid aerosol deposited on filters of varying efficiency. Results were modeled using two semi-empirical models for identifying the basic parameters of liquid aerosol evaporation on fibers. For the first time ever it has been demonstrated that the Fick's first law, as previously suggested by models proposed in the literature, does not control evaporation kinetic.

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