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Additional file 1: Supplemental Table S1. Average exposure level of the three different professional groups. Supplemental Table S2. Geomtric concentration of the selected variables in EBC samples collected during the two working weeks for the three professional categories. Supplemental Figure S1. Effect of the professional activity on the predicted EBC levels of MDA. Supplemental Table S3. Averaged EBC concentration of selected anions in pre- and post-shift for all volunteers.

The oxidative potential (OP) of particulate matter has been proposed as a toxicologically relevant metric. This concept is already frequently used for hazard characterization of ambient particles but it is still seldom applied in the occupational field. The objective of this study was to assess the OP in two different types of workplaces and to investigate the relationship between the OP and the physicochemical characteristics of the collected particles. At a toll station, at the entrance of a tunnel ('Tunnel' site), and at three different mechanical yards ('Depot' sites), we assessed particle mass (PM4 and PM2.5 and size distribution), number and surface area, organic and elemental carbon, polycyclic aromatic hydrocarbon (PAH), and four quinones as well as iron and copper concentration. The OP was determined directly on filters without extraction by using the dithiothreitol assay (DTT assay-OP(DTT)). The averaged mass concentration of respirable particles (PM4) at the Tunnel site was about twice the one at the Depot sites (173±103 and 90±36 µg m(-3), respectively), whereas the OP(DTT) was practically identical for all the sites (10.6±7.2 pmol DTT min(-1) μg(-1) at the Tunnel site; 10.4±4.6 pmol DTT min(-1) μg(-1) at the Depot sites). The OP(DTT) of PM4 was mostly present on the smallest PM2.5 fraction (OP(DTT) PM2.5: 10.2±8.1 pmol DTT min(-1) μg(-1); OP(DTT) PM4: 10.5±5.8 pmol DTT min(-1) μg(-1) for all sites), suggesting the presence of redox inactive components in the PM2.5-4 fraction. Although the reactivity was similar at the Tunnel and Depot sites irrespective of the metric chosen (OP(DTT) µg(-1) or OP(DTT) m(-3)), the chemicals associated with OP(DTT) were different between the two types of workplaces. The organic carbon, quinones, and/or metal content (Fe, Cu) were strongly associated with the DTT reactivity at the Tunnel site whereas only Fe and PAH were associated (positively and negatively, respectively) with this reactivity at the Depot sites. These results demonstrate the feasibility of measuring of the OP(DTT) in occupational environments and suggest that the particulate OP(DTT) is integrative of different physicochemical properties. This parameter could be a potentially useful exposure proxy for investigating particle exposure-related oxidative stress and its consequences. Further research is needed mostly to demonstrate the association of OP(DTT) with relevant oxidative endpoints in humans exposed to particles.

Contexte La prevention des effets respiratoires lies aux expositions professionnelles a des aerocontaminants est un enjeu important pour les medecins du travail. Entre 20 et 30 % des bronchites chroniques obstructives (BPCO) sont liees a des expositions professionnelles, comme les particules fines ou ultrafines, qui peuvent induire un stress oxydant. Des biomarqueurs du stress oxydant pourraient etre proposes pour le depistage precoce des effets respiratoires, notamment de la BPCO, a condition d’etre valides et mesurables dans des prelevements biologiques peu invasifs. Methodes Une revue de litterature sur les biomarqueurs pertinents pour la surveillance de travailleurs a ete realisee, puis un projet de recherche collaborative entre l’IST et l’UPST-RATP a ete propose pour selectionner et valider les biomarqueurs du stress oxydatif non invasifs. Resultats Le projet Respiratory disease Occupational Biomonitoring Collaborative Project (ROBoCop) est bâti dans le cadre du consortium europeen CliniMark (Action EU-COST CA16113) et soutenu par le Fonds national suisse de la recherche scientifique. Il comporte trois parties : 1. Standardisation du recueil des echantillons biologiques (condensat d’air exhale, urine) et des methodes d’analyses des biomarqueurs retenus (8-isoprostane, malondialdehyde, NO2−, NO3−, ions formates et 8-hydroxy-2’deoxyguanosine) et validation de l’analyseur OPEA (oxidative potential in the exhaled air) developpe par l’IST (Brevet EU et Etats-Unis). 2. Etude pilote a la RATP pour definir le protocole d’echantillonnage standardise et evaluer la faisabilite de la mesure des biomarqueurs selectionnes chez les travailleurs exposes aux particules fines et ultrafines. 3. Etude de terrain sur 300 travailleurs volontaires de la RATP, selectionnes par randomisation stratifiee (âge, tabac, exposition professionnelle) sur les 45 000 travailleurs suivis par les 34 medecins de l’entreprise. Les donnees issues des consultations medicales (examen clinique + spirometrie) et de l’analyse des echantillons biologiques seront analysees afin de rechercher une correlation entre les biomarqueurs etudies et la survenue d’un syndrome obstructif. Conclusion Ce projet permettra d’elaborer des protocoles standardises et des recommandations de bonne pratique pour l’usage des biomarqueurs du stress oxydatif a partir des prelevements non invasifs, dans un service de sante au travail. Il permettra de valider l’utilisation de biomarqueurs pour le depistage de la BPCO chez les travailleurs exposes, voire pour le depistage en population generale, ou pour le suivi medical de patients atteints par cette pathologie.

International audience; Epidemiological studies in urban areas have linked increasing respiratory and cardiovascular pathologies with atmospheric particulate matter (PM) from anthropic activities. However, the biological fate of metal-rich PM industrial emissions in urban areas of developed countries remains understudied. Lead toxicity and bioaccessibility assessments were therefore performed on emissions from a lead recycling plant, using complementary chemical acellular tests and toxicological assays, as a function of PM size (PM10–2.5, PM2.5–1 and PM1) and origin (furnace, refining and channeled emissions). Process PM displayed differences in metal content, granulometry, and percentage of inhalable fraction as a function of their origin. Lead gastric bioaccessibility was relatively low (maximum 25%) versus previous studies; although, because of high total lead concentrations, significant metal quantities were solubilized in simulated gastrointestinal fluids. Regardless of origin, the finest PM1 particles induced the most significant pro-inflammatory response in human bronchial epithelial cells. Moreover, this biological response correlated with pro-oxidant potential assay results, suggesting some biological predictive value for acellular tests. Pulmonary effects from lead-rich PM could be driven by thiol complexation with either lead ions or directly on the particulate surface. Finally, health concern of PM was discussed on the basis of pro-inflammatory effects, accellular test results, and PM size distribution

International audience; The combustion conditions determine to a large extent the bulk and interfacial properties of the resulting combustion aerosol (soot). The complex chemical and physical nature of combustion aerosol in general precludes the complete chemical characterization of both bulk and interfacial components using analytical chemistry. Our vision is that the bulk composition reveals the flame conditions whereas the interface reflects aging and controls the interaction with solid surfaces (adhesion to supports) as well as with biological membranes (health effects, oxidative stress induced by particles, etc.). We have therefore developed a soft interrogation technique of the interfacial functional groups using heterogeneous chemistry of probe gases of differing reactivity. This procedure represents a minor perturbation of the aerosol particle compared to bulk analysis.In order to chemically characterize the surface of aerosol particles in terms of functional groups present on the particulate surface up to six probe gases (N((CH3)3), NH2OH, CF3COOH, HCl, NO2, O3) were selected to probe combustion aerosol (amorphous carbon, flame soot, Diesel engine soot) and sampled aerosol from several bus depots using heterogeneous reactions. Briefly, the method rests upon measuring the rate of uptake of a probe gas under molecular flow conditions in the presence of deposited aerosol particles. The gas uptake to saturation of the probes was measured in a Knudsen flow reactor and expressed as a density of surface functional groups on a particular aerosol whose size distribution was measured. The probe gases taken up by the sample addressed acidic (carboxylic) and basic (oxides such as pyrones and N-heterocycles) sites, carbonyl (R1-C(O)-R2) and oxidizable (olefinic, certain -OH) groups. The used probes were able to characterize the surface of the particles in terms of the oxidation state (oxidized, partially oxidized, oxidizable or reduced) and olefinic or surface-adsorbed, therefore reactive, polycyclic aromatic compounds. The limit of detection was generally well below 1% of a formal molecular monolayer. With few exceptions most investigated aerosol samples and nanometric materials (soot) interacted with all probe gases which points to the coexistence of different functional groups on the same aerosol surface such as acidic and basic groups. Generally, there were significant differences in surface group density: Printex 60 amorphous carbon had the lowest density of surface functional groups throughout, whereas Diesel soot recovered from a Diesel particulate filter had the largest. The presence of basic oxides on carbonaceous aerosol particles was inferred from the ratio of uptakes of CF3COOH and HCl owing to the larger stability of the acetate compared to the chloride counterion in the resulting pyrylium salt. Both soots generated from a rich and a lean hexane diffusion flame had a large density of oxidizable groups similar to amorphous carbon FS 101.