Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Enactment of regulatory standards for respirable coal mine dust (RCMD) concentration and crystalline silica content, and advancements in mine ventilation and dust controls led to a steady decline of occupational lung disease among US coal miners between the early 1970s and the mid-1990s. Since that time, there has been an alarming resurgence of disease especially in central Appalachia—with little hard data to pinpoint the causative factors in the mine environment. This situation has emphasized the knowledge gap surrounding specific dust characteristics and their sources. Key observations from many disease cases have suggested that dust constituents sourced from the rock strata in the mine (i.e., the rock layers that surround the target coal seam) may be particularly important; and this fits with the general tendency to extract thinner coal seams, and thus more rock, in many central Appalachian mines. To explore the characteristics of rock-strata sourced dust and its possible influence on the overall RCMD, this thesis reports two primary research efforts: Chapter 1 encompasses a case study conducted in an underground coal mine in West Virginia. (This chapter was previously published in the proceedings of the 18th North American Mine Ventilation Symposium, and is being reproduced with permission of the licensor through.) Following precedent from other studies, respirable dust samples were collected from key locations including in the intake airway, downwind an operating roof bolter, and adjacent to the feeder breaker. Additionally, three locations downwind the production face were simultaneously sampled during four individual continuous miner cuts—which was a unique feature of the current study. Dust was analyzed using previously established methods, including scanning electron microscopy with energy dispersive X-ray (SEM-EDX) to determine particle size and mineralogy distributions. Where comparable, results were generally consistent with those from other central Appalachian mines. However, the unique production sampling scheme offered new insights regarding the shift in particle characteristics as dust moves downwind from the generation point. Changes in size and mineralogy suggested that rock-strata sourced particles, especially aluminosilicates, might interfere with the SEM-EDX classification of other particles, especially coal. To explore the issue of aluminosilicate interference with coal classification, and the possible reasons, Chapter 2 covers two main lines of study. First, existing RCMD samples and SEM-EDX metadata were re-examined. Results suggested that particle loading effects could be at least partly responsible for the appearance of inordinately high aluminosilicate abundance (and conversely low coal) in some samples (i.e., the mineral particles might deposit on the sample filter in close proximity to the coal). Additionally, the presence of coal-mineral microagglomerates (MAGs) was demonstrated. The second line of study in Chapter 2 was therefore to explore whether MAG formation could be due to the RCMD generation process or environmental conditions—rather than merely an artifact of the sampling procedure—and the dispersibility of MAGs, which may have important implications with respect to dust exposure and biological response. Laboratory-generated samples collected passively demonstrated that coal-mineral MAGs can indeed occur without influence from typical RCMD sampling equipment. MAGs were significantly dispersed by sonication in deionized water, though gentle swirling did not yield consistent results. Moreover, in a surfactant solution that mimics natural lung fluid, MAGs were also dispersed. Compared to deionized water, the surfactant may promote more dispersion of coal particles in particular. / Master of Science / Occupational illnesses such as black lung in underground coal mining are still a worrisome issue in the industry. This research was aimed at gaining insight into rock-strata sourced dust and its possible influence on the overall characteristics of respirable coal mine dust (RCMD). The rock strata surrounding the coal seam is often rich in silicates and silica. A case study of RCMD was conducted in a thin-seam mine in West Virginia. Samples were collected in various locations and analyzed using electron microscopy among other methods. Results indicated that mineral dust, especially aluminosilicates, can be very abundant near the production face and might interfere with the measurement of coal dust. To explore such interference, a follow-up study was performed by revisiting a subset of RCMD samples examined in prior work. This approach yielded evidence of coal-mineral microagglomerates. Additional efforts in the laboratory recreated agglomerate formation and demonstrated their dispersibility. Results suggested that the occurrence of microagglomerates is not entirely a direct consequence of the sampling methodology and highlighted their potential importance within the context of exposure assessment and possible biological response.

Following the promulgation of new permissible respirable dust standards by MSHA in 2014, new alternative rock dusts were created that combined the advantages of current industry applications while potentially reducing miner exposure to respirable dust. Research was performed to compare the explosion suppressing and ejection characteristics of three new types of rock dust to existing rock dust types. Explosion suppression tests were conducted in a 38-L chamber where pressures were recorded. Angle of ejection tests were conducted using a high explosive shock tube and high speed photography to determine angle of ejection and lift velocity. A comprehensive comparison of the results of these tests shows that these newly developed dusts have improved results for flame suppression and ejection when compared to typical wet dust applications.

The aims of the studies underlying this thesis were to assess the exposure to quartz in Swedish iron foundries and to determine the cancer morbidity for Swedish foundry workers. A cohort of 3,045 foundry workers and a final measurement database of 2,333 number of samples was established. The exposure measurements showed high levels of respirable quartz, in particular for fettlers and furnace and ladle repair workers with individual 8 hr TWA (GM=0.041 and 0.052 mg/m3; range 0.004-2.1 and 0.0098-0.83 mg/m3). In our database, the quartz concentrations as 8hr TWAs of current and historical data varied between 0.0018 and 4.9 mg/m3, averaging 0.083 mg/m3, with the highest exposures for fettlers (0.087 mg/m3) and furnace and ladle repair workers (0.42 mg/m3). The exposure for workers using respirators assuming full effect when used were assessed quantitatively, revealing workers with actual exposure exceeding the occupational exposure limits. Overall cancer morbidity was not increased, but the incidence of lung cancer was significantly elevated (SIR 1.61; 95 % CI 1.20-2.12). In the cohort study, significant associations between lung cancer and cumulative quartz exposure were detected for quartz doses of 1-2 mg/m3 * year (SIR 2.88; 95 % CI 1.44-5.16) and >2 mg/m3 * year (SIR 1.68; 95 % CI 1.07- 2.52). These findings were not confirmed in the case-control analysis. The agreement between the estimated exposure in our early historical model and the development model showed a regression coefficient of 2.42, implying an underestimation of the historical exposure when using the development model data. The corresponding comparison between the development and the validation model based on our survey data showed a B of 0.31, implying an overestimation of present exposures when using data from the validation model. The main conclusions of the thesis are that certain foundry workers are still exposed to high levels of quartz, and the overall excess lung cancer could not be confirmed in the exposure-response analysis.

Class of 2012 Abstract / Specific Aims: To evaluate the in vitro throat deposition and respirable mass of the QVAR® pressurized metered-dose inhaler (pMDI) alone or coupled to an accessory device, such as the AeroChamber Valved Holding ChamberTM or various nonconventional accessory devices. Methods: The performance of the AeroChamber and nonconventional accessory devices, including a toilet paper roll, paper towel roll, rolled paper, plastic bottle spacer, plastic bottle reverse-flow holding chamber, and nebulizer reservoir tubing, were compared to no accessory device. Throat deposition and respirable mass were evaluated using a United States Pharmacopeia (USP) inlet ("throat") coupled to instrumentation for particle size analysis. Each configuration was tested with three actuations and repeated in quadruplicate. The amount of drug deposition was quantified using high-performance liquid chromatography. The data were analyzed using multiple independent t-tests assuming unequal variances. An a priori α-threshold of 0.05 was used with a Bonferroni corrected α of 0.007. Main Results: Compared to the pMDI alone, all of the accessory devices had significantly lower throat deposition (p < 0.001) and significantly higher respirable fraction (p < 0.001). Differences in respirable mass were not significant for any accessory device (p ≥ 0.049), except the paper towel roll and the nebulizer reservoir tubing (p < 0.001). Conclusions: Under these testing circumstances, nonconventional accessory devices, such as the toilet paper roll, rolled paper, plastic bottle spacer, and plastic bottle reverse-flow holding chamber, effectively reduce throat deposition and maintain respirable mass compared to a QVAR pMDI alone. Therefore, they may be suitable alternatives to commercial spacers.

Concentration levels of PM2.5 and PM10 paper dust were measured in a book production facility using a quantitative single subject study. Dust concentration data was collected in three processes of a book manufacturing facility; paper recycling, the digital pressroom and the digital bindery. Data was collected using the DustTrak DRX 8533 Aerosol Monitor, focusing on particulate sizes of PM2.5 and PM10. The data was used to determine if paper dust in the book production industry reached concentration levels that could have negative respiratory health effects on surrounding employees and to determine which process within the studied facility had the highest concentrations of paper dust. The study revealed that the paper recycling warehouse had the highest concentrations of paper dust. It was also determined that the paper recycling warehouse could cause negative respiratory health effects on surrounding employees. Further research is needed to determine the extent of those effects and potential remediation.

Sammanfattning Stendamm förekommer på alla väg och anläggningsprojekt men kunskapen om hur farligt det är att exponeras för de respirabla kvartspartiklar som stendamm innehåller är bristfällig. Det respirabla kvartsdammet kan framkalla bland annat Silikos och cancer i lungorna men även påverka hjärtat negativt då lungornas funktion blir nedsatt. Syftet med rapporten var att undersöka hur bra information och kunskap det finns om kvarts i stendamm samt hur och om olika åtgärder som exempelvis andningsskydd förekommer. Då tiden för examensarbetet är begränsat avgränsas en del informationshämtning till Skanska AB väg och anläggning i region mitt. En enkät arbetades fram och användes som metod för att ta reda på dagens kunskapsnivå hos Skanska samt hur bra Skanska informerar när det gäller kvarts. Denna skickades ut till samtliga anställda på Skanska AB väg och anläggning i region mitt. Intervjuer gjordes också med personer som har en chefsroll eller tillhör arbetsledningen inom Skanska AB. Enkätundersökningens resultat visade att kunskapen om kvarts i stendamm finns hos de flesta anställda men att informationen bör bli bättre och upprepas oftare. Resultatet visade även att användandet av andningsskydd är bristfällig då det är jobbigt att andas i och att det blir varmt att bära det en hel dag. Det framkom även att personlig andningsutrustning inte fanns att tillgå för alla som har ett behov av det. En guide togs fram som ett resultat från enkäten och intervjuer. Guiden ska hjälpa arbetsledningen med hur de kan förebygga exponering för kvartsdamm i sina projekt samt ge yrkesarbetare en information som ska påminna om de enklare sätten att skydda sig mot stendamm. Under rubriken diskussion diskuteras bland annat möjligheterna om att använda olika hygieniska gränsvärden inom olika näringsgrenar, detta för att ett sänkt gränsvärde inom väg och anläggning skulle kunna leda till hårdare arbete för en ännu bättre arbetsmiljö. Kunskapen om hur hälsan kan påverkas av respirabelt kvarts kan alltid bli bättre och det gäller särskilt yrkesarbetare som främst utsätts för stendamm. Slutsatserna för detta examensarbete blev att arbetstagare som riskerar att utsättas för stendamm bör informeras oftare, helst inför varje nyetablerad arbetsplats, samt att behovet av personliga andningsskydd med tillhörande utbildning bör överses. Vidare konstaterades att arbetsberedningen som görs i riskbedömningen bör utföras av personer som har fått en likvärdig utbildning så att tiden för arbetsberedning kan effektiviseras samt att alla arbetsberedningar blir konsekventa i sitt utförande. / Stone dust exists in all road and public work projects yet the knowledge about how dangerous exposure to the respirable quartz particles that stone dust contains is lower than what could be preferred. The respirable quartz can cause silicosis and lung cancer as well as heart diseases when the capacity of the lungs is reduced. The purpose of this project was to investigate if there is sufficient information and knowledge about quartz in stone dust in this business today. The purpose was also to realize whether there are quartz-prohibiting measures, such as the usage of breathing aid, taken or not. Because of the time-limit of this project much of the gathering of information was limited to “Skanska AB väg och anläggning, region mitt”. A survey was produced and used as a method in order to get information about the level of knowledge that Skanska employees have, as well as how good Skanska is at informing their employees, about quartz. This survey was sent to all of Skanska Sweden’s staff members in road and public works, central region. In addition to this, interviews were held with supervisors and managers in the same region. The survey results revealed that most employees have some sort of knowledge about quartz but that the information should be made more extensive and be repeated more often. The results also show that the usage of personal breathing aid is inadequate, this is because the aid is hard to breathe through and during long and warm days they’re an annoyance to wear. In addition, it was also brought to light that not everyone who needs a breathing aid have access to one. As another result of the survey and the interviews a guide was made. This guide was formed as a helping hand for the staff management when they’re making risk evaluations and work preparations but also as a short information for all staff members to make it easier for them to remember the easiest and most efficient ways to avoid and protect yourself from quartz particles. In the discussion the possibilities about lowering the hygienic limits of quartz for different parts of the economy was debated. A lowering of the hygienic limit in road and public works should lead to more work, such as this, being done towards a better work environment. The knowledge about how personal health is affected by respirable quartz can always get better and that goes especially for employees that work in direct contact with stone dust. The conclusions of this project were that employees that are exposed to stone dust should be informed more often, preferably before the start of every project, and also the need for personal breathing aid with appurtenant education should be attended to. Furthermore, the work preparations made with every risk evaluation should always be made by staff members with the same qualifications and information. Thus, all work preparations will look consistent and also, the creation of them will be more time efficient.

In this study, we developed and standardized a sanding method to evaluate the emission of airborne particles from products that contain carbon nanotubes (CNTs) under different conditions, including three types of sandpaper and three sanding disc speed. We also characterized the emission of the airborne particles from one neat epoxy test sample, four CNTs-incorporating test samples with different CNTs loading, and two commercial products. The total number concentration, respirable mass concentration, and particle size number/mass distribution of the emitted particles were calculated and compared, followed by an electron microscopy (EM) analysis. These data suggest that the sanding process can produce substantial quantities of airborne particles. Also, the emission of airborne particles was associated with different test conditions. EM analysis of the airborne particle samples showed embedded CNTs protruding from the outer surface, which was different from CNTs-incorporating bulk material. Our study suggests a potential generation of particles during the life cycle event of sanding. Further studies should be carried out to investigate the potential human health hazard in other life cycle events.

This thesis dissertation assessed workers who work in poultry barns and their occupational environment in relation to the type of bird housing in which they were exposed (cage-housed birds (CH) or floor-housed birds (FH)) and examined the environmental variables including dust and endotoxin and potential relationships to respiratory symptoms of workers. <p>A cross sectional study was undertaken to assess the environmental exposure levels and respiratory health effects of workers who worked in CH and FH poultry operations. The respiratory results suggested an asthma-like syndrome in these workers. Workers who worked in CH facilities reported greater current and chronic respiratory symptoms and significantly greater current and chronic phlegm as compared to workers from FH facilities. Workers from CH poultry facilities were exposed to greater endotoxin load than workers from FH facilities, but workers from FH operations were exposed to greater levels of total dust. It was found that endotoxin load (EU/mg) was a significant predictor of chronic phlegm for all poultry workers.<p>The effects on dust and endotoxin measurements when utilizing a Marple impactor with greased or ungreased impaction surfaces when sampling in an agricultural environment were unknown, and the potential for effects was tested. There were no significant differences in the aerosol mass median aerodynamic diameters between the greased and ungreased Marple impactors. Endotoxin analysis results appeared to be influenced by impaction grease particularly when very low amounts of endotoxin were present. <p>Size fractioning the dust and endotoxin using Marple impactors in CH and FH poultry operations showed that endotoxin load (EU/mg) was significantly higher in the respirable fraction of area samples in CH poultry operations as compared to FH operations. There were no differences in endotoxin load in the non-respirable size fractions for area samples between CH and FH operations. FH poultry operations had significantly greater dust mass and dust concentration in both respirable and non-respirable fractions for FH operations. There was significantly greater endotoxin load (EU/mg) in the 3.5-6.0 micron size fraction for the CH poultry operations as compared to the FH operations.

This thesis dissertation assessed workers who work in poultry barns and their occupational environment in relation to the type of bird housing in which they were exposed (cage-housed birds (CH) or floor-housed birds (FH)) and examined the environmental variables including dust and endotoxin and potential relationships to respiratory symptoms of workers. <p>A cross sectional study was undertaken to assess the environmental exposure levels and respiratory health effects of workers who worked in CH and FH poultry operations. The respiratory results suggested an asthma-like syndrome in these workers. Workers who worked in CH facilities reported greater current and chronic respiratory symptoms and significantly greater current and chronic phlegm as compared to workers from FH facilities. Workers from CH poultry facilities were exposed to greater endotoxin load than workers from FH facilities, but workers from FH operations were exposed to greater levels of total dust. It was found that endotoxin load (EU/mg) was a significant predictor of chronic phlegm for all poultry workers.<p>The effects on dust and endotoxin measurements when utilizing a Marple impactor with greased or ungreased impaction surfaces when sampling in an agricultural environment were unknown, and the potential for effects was tested. There were no significant differences in the aerosol mass median aerodynamic diameters between the greased and ungreased Marple impactors. Endotoxin analysis results appeared to be influenced by impaction grease particularly when very low amounts of endotoxin were present. <p>Size fractioning the dust and endotoxin using Marple impactors in CH and FH poultry operations showed that endotoxin load (EU/mg) was significantly higher in the respirable fraction of area samples in CH poultry operations as compared to FH operations. There were no differences in endotoxin load in the non-respirable size fractions for area samples between CH and FH operations. FH poultry operations had significantly greater dust mass and dust concentration in both respirable and non-respirable fractions for FH operations. There was significantly greater endotoxin load (EU/mg) in the 3.5-6.0 micron size fraction for the CH poultry operations as compared to the FH operations.