Documents determination in air 69 results

"Available industry guidelines and federal standards have failed to fully protect workers from chemical toxicity: none exist for most chemicals, many are biased toward what can easily be achieved, and many were developed long after health consequences became evident. Limitations of occupational air contaminant standards in the United States are well illustrated by standard-setting for the neurotoxin n-hexane. In the 1940s, the American Conference of Governmental Industrial Hygienists (ACGIS) first promulgated industrial guidelines known as "threshold limit values" (TLVs), including an 8-hour time-weighted average of 500 ppm for inspired n-hexane. Despite subsequent recognition of the neurotoxicity of n-hexane with industrial outbreaks of polyneuropathy beginning in the 1960s, the TLV for n-hexane remained unchanged until 1976 when a value of 100 ppm was adopted. Because a growing number of clinical reports have identified clinical and subclinical neurotoxicity from n-hexane near, at, and below the current time-weighted average TLV of 50 ppm, even this level is too high to protect all workers. In part due to procedural and political constraints, the Occupational Safety and Health Administration (OSHA) has independently developed only a small number of exposure standards in the past 25 years, and has been incapable of providing needed revisions for existing standards. Most OSHA standards--including those for n-hexane--were adopted in 1971 from the 1968 ACGIH TLVs and have never been revised. From 1971 to 1989 the OSHA permissible exposure level (PEL) for n-hexane remained at 500 ppm, 5-10 times as great as other contemporary standards. To help correct its regulatory backlong, OSHA promulgated 375 new or revised PELs in 1989--including a new standard of 50 ppm for n-hexane--but all of these were vacated by the 11th U.S. Court of Appeals in 1992. As a result, the current OSHA PEL for n-hexane remains at the 500 ppm level adopted in 1971, which even then was too high based upon available scientific evidence. New information over this long period, including that obtained from industrial outbreaks of disease due to chemical exposures, has not been incorporated into revised federal standards."

"A longitudinal study was carried out on two groups of workers engaged in tin/lead alloy welding in the telecommunications sector. The risk of exposure was evaluated by measuring levels of airborne lead and concentrations of lead in blood. The correlated effects were assessed by determining zinc protoporphyrin(ZPP) and haemoglobin levels and red blood cell count. Subjective symptoms were also recorded. Results indicated a very low risk of lead exposure during microwelding operations. While blood lead concentrations were significantly higher than those in the general population, they were significantly lower than the Occupational Safety and Health Administration's permissible exposure limit. No variation was found in the other biological parameters investigated, and no health effects were observed. During the study period, the introduction of some technological innovations led to a further reduction in lead exposure and,subsequently, to its total elimination. Blood lead concentrations gradually declined to lower values, and ZPP concentrations also decreased to normal levels, demonstrating that the effect of lead on heme synthesis may occur even at very low levels of lead exposure."

"This criteria document on particles in ambient air has been prepared at the Institute of Environmental Medicine, Karolinska Institutet, at the request of the Swedish Environmental Protection Agency. Although each chapter has main authors, the work has been a joint effort, and all conclusions and recommendations have been thoroughly discussed by the group. Besides the authors, the group included Carl-Elis Boström and Titus Kyrklund from the Swedish Environmental Protection Agency. Furthermore, a draft of the document was discussed with a reference group including Bertil Forsberg, Hans-Christen Hansson, Thomas Sandström, and Katarina Victorin. The main focus of the document is on effects other than cancer since particles in the ambient air were recently evaluated as a risk factor for cancer by the Institute of Environmental Medicine. In general, literature published through 1998 is reviewed, with occasional inclusion of important work published thereafter. However, the chapter on epidemiologic studies was prepared earlier and primarily relates to reports published through 1997."

"Les Archives de France ont mis en place un protocole prenant en compte le risque d'importation d'une contamination lors du versement de fonds provenant de locaux comportant des matériaux et produits contenant de l'amiante. La présence d'amiante dans l'air lors du test de manipulation entraîne alors la décontamination des archives et du local par une entreprise certifiée, et l'enregistrement des expositions du personnel concerné. Il convient de préciser qu'avant son interdiction, l'amiante utilisé dans les matériaux de construction en France était majoritairement du chrysotile (95 %), de la crocidolite et de l'amosite. Lorsque des prélèvements surfaciques effectués ont mis en évidence des fibres d'anthophyllite pour deux séries de documents, alors que les prélèvements d'air dans les magasins correspondants étaient négatifs, les Archives de Paris ont demandé l'appui de l'INRS pour déterminer l'origine de la contamination par cette variété d'amiante. Annexe : Ce complément à l'étude de cas présente un ensemble de recherches menées pour déterminer l'origine possible des fibres d'anthophyllite — amiante identifiées lors de cette étude."

"La surveillance des niveaux de contamination de l'air par des nanomatériaux manufacturés (NMM) est une démarche complexe qui présente plusieurs incertitudes et limites notamment : la présence simultanée de particules de dimensions nanométriques qui ne sont pas des NMM, l'absence d'instruments validés permettant une mesure en zone respiratoire et la multiplicité des indicateurs à apprécier. Certains organismes, dont l'Institut national de recherche et de sécurité (INRS) en France et l'Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) au Québec soulignent aussi la nécessité de réaliser des prélèvements surfaciques afin d'attester la présence de dépôts de NMM. Le perfectionnement des techniques existantes et l'élaboration de nouvelles méthodes de prélèvement et de caractérisation des NMM sont donc nécessaires en vue d'une meilleure évaluation globale du risque d'exposition des travailleurs. C'est dans ce cadre que s'inscrit ce projet dont l'objectif général est de développer des approches méthodologiques originales permettant une caractérisation poussée de l'exposition aux NMM dans les milieux de travail, sur les plans qualitatif et quantitatif."

"As workplace air measurements of manufactured nanoparticles are relatively expensive to conduct, models can be helpful for a first tier assessment of exposure. A conceptual model was developed to give a framework for such models. The basis for the model is an analysis of the fate and underlying mechanisms of nanoparticles emitted by a source during transport to a receptor. Four source domains are distinguished; that is, production, handling of bulk product, dispersion of ready-to-use nanoproducts, fracturing and abrasion of end products. These domains represent different generation mechanisms that determine particle emission characteristics; for example, emission rate, particle size distribution, and source location. During transport, homogeneous coagulation, scavenging, and surface deposition will determine the fate of the particles and cause changes in both particle size distributions and number concentrations. The degree of impact of these processes will be determined by a variety of factors including the concentration and size mode of the emitted nanoparticles and background aerosols, source to receptor distance, and ventilation characteristics. The second part of the paper focuses on to what extent the conceptual model could be fit into an existing mechanistic predictive model for ''conventional'' exposures. The model should be seen as a framework for characterization of exposure to (manufactured) nanoparticles and future exposure modeling."

"Les allergies professionnelles comptent parmi les maladies professionnelles les plus fréquentes, car nombre de substances et d'organismes sensibilisants sont présents en milieu de travail. Souvent sous-estimées, ces pathologies peuvent pourtant devenir très invalidantes et conduire à des réorientations professionnelles. Ce dossier propose un état des lieux des connaissances sur la fréquence de ces pathologies dans le monde du travail et sur les mécanismes physiopathologiques mis en jeu. Il présente également différents axes de prévention des risques : des tests permettant de prédire le pouvoir sensibilisant cutané des produits chimiques, des méthodes de mesure des allergènes dans l'air des lieux de travail ainsi qu'un exemple de méthode d'évaluation de l'émissivité de machines en poussières de farine.Il se compose de 5 articles :- Quelques données épidémiologiques sur les allergies professionnelles- Les manifestations et mécanismes des allergies professionnelles- Des tests pour prédire le pouvoir sensibilisant cutané des produits chimiques- Mesurer les allergènes fongiques dans l'air des lieux de travail- Une méthode d'évaluation de l'émissivité des machines en poussières de farine."