The mutagenicity of 4-monochlorobiphenyl (PCB3) in the liver of male 344 Fisher transgenic rats has been established by Lehmann et al (2007). The evidence that PCBs can be deposited in the lung and bound to a protein creates a need to assess the effect of mutagenic effect of PCBs in the lung. The goal of this study was to assess the mutagenicity of PCB3 in the lung of male 344 Fisher transgenic rats. Big Blue® 334 Fisher transgenic rats were given weekly intraperitoneal injections with corn oil as a negative control, 3-methylcholanthrene (3-MC) as a positive control, PCB 3 or 4-hydrox-PCB 3 (4-OH- PCB 3) weekly for 4 weeks. Lungs were removed and analysis performed to determine mutant frequency, mutation spectra, and pathological changes. There was a 2-fold increase in mutant frequency after treatment with PCB 3 and 4- OH-PCB 3 that was not statistically significant. There were changes in the mutation spectra after treatment with PCB 3 or 4- OH-PCB 3. This study shows that PCB 3 and 4-OH-PCB 3 may create mutations in the lung following exposure.

A shaker dust collector was evaluated to 1. determine filter capacity in terms of mass loading, pressure drop, airflow, and runtime; 2. determine particle collection efficiency by size prior to and following repeated loadings. A shaker dust collector was setup in the laboratory to take in contaminated air, collect dust, and exhaust treated air. For each loading test, Arizona road dust (~1 to 200 μm) was introduced into the airstream entering the dust collector at an emission rate and duration equivalent to 3-months in a swine barn in winter. Filter pressure drop and exhaust velocity pressure were measured throughout loading. Filter collection efficiency was tested using polydisperse solid glass microspheres (~1 to 10 μm) and measured with an aerodynamic particle sizer at the startup and end of loadings. Cleaning cycles were run between loading tests. Overall efficiency was 44% for new filter, and ranged from 27% for 1-μm particles, increasing to 96% for 10-μm particles. Collection efficiency for loaded filter was 99% overall, and 99% over the range of 1 to 10-μm particles. Following cleaning, overall efficiency was 91%, and 91% for 1-μm particles, increasing to 99% for 10-μm particles. Exhaust airflow decreased linearly with pressure drop (r2=0.99) for all three loading tests. At shutdown, system airflows were approximately 700 cfm. Significant recovery of filter residual pressure was observed following primary and secondary cleanings (p<0.001). High removal efficiency was achieved after an initial loading period. The shaker dust collector filter is anticipated to be sufficient to treat air continuously in a swine barn over a 3-month winter period. The engineering control system is recommended for further testing to improve indoor air quality inside a Midwestern farrowing barn during winter.

Data from the Environmental Protection Agency’s Building Assessment and Survey Evaluation (BASE) study was analyzed for culturable fungi detected in air samples collected from 100 office buildings located among ten climate regions in the United States. Fungi identified and quantified in the study were evaluated in indoor and outdoor environments. Evenness of species for both summer and winter, and the diversity and similarity indices of species were calculated between climate region groups in order to observe potential climate-based differences in the fungal microbiome. Respiratory and neurological health symptoms of study building occupants (n = 4,326) were self-reported by questionnaire, and were analyzed in order to assess seasonal and climate differences.

General noise regulations and guidelines protect workers against 8-hour time-weighted average noise exposures > 85-90 dBA that can cause health outcomes and noise induced hearing loss (NIHL), but the bus transportation industry has guidelines limiting lower noise exposures > 75-80 dBA to reduce safety hazards, including distraction and poor communication. These hazards can create dangerous driving conditions, especially for urban bus drivers, potentially causing a collision. Further research was necessary to characterize U.S. urban transit bus driver noise exposures to assess whether they exceeded 75, 80, 85, and 90 dBA, time-weighted, and to identify statistically significant noise exposure risk factors for this local transit system. Time-weighted average noise exposures collected from the local transit system, a small urban bus system serving a university in Iowa City, showed the majority of drivers did not exceed 85 dBA due to short shift times, but these drivers may have been at a safety risk for distractions and poor communication due to loud environments > 75-80 dBA. The driver's AM/FM radio was a statistically significant risk factor (p = 0.004) affecting driver-shift TWA noise exposures. Projected noise exposure calculations showed that with bus driver shifts greater than or equal to 8 hours, the TWA noise exposures measured may exceed 85 dBA. Actual 8- hour time-weighted average noise exposures using sequential bus driver shifts did not exceed 90 dBA.

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Infectious diseases account for over 15 million deaths worldwide. Those who are at greatest risk of contracting an infectious disease are immunocompromised. These individuals may be admitted to a healthcare-based setting where they may become infected. In the United States, 1.7 million immunocompromised individuals contract a healthcare-associated infection which lengthens stay, increases medical costs, and puts lives at stake. The transmission routes for these infections occur from direct contact with healthcare staff and contaminated surfaces. Indirect contact methods, such as bioaerosols suggest, but are not a well-examined route of infection. One possible bioaerosol generator includes the flushing of loose stools in toilets from infected patients. To date, no study has investigated the particle or bioaerosol changes in the air resulting from toilet flushing loose fecal wastes in a healthcare setting. The purpose of this study was to investigate changes in the air before and after a toilet flush to support hypotheses that toilets can produce an aerosol containing viable microorganisms, potentially spreading infectious disease. Particle and bioaerosol concentrations were measured in hospital bathrooms across 3 sampling conditions; no waste no flush, no waste with flush, and fecal waste with flush. Particle concentrations were measured with a particle counter 3 minutes before a flushing event and throughout the bioaerosol collection period. Bioaerosol concentrations were measured with BioStage impactors fixed on a sampling cart at distances of 0.15, 0.5, and 1 m that was placed in front of a toilet. For each sampling trial, 3 time measurements were recorded after a flushing event (i.e., 5, 10, 15 minutes). Particle concentrations measured before and after the flush were found to be significantly different in 0.3 (p-values= 0.002, 0.002, 0.015), 0.5 (p-values= 0.002, 0.002, 0.018), 1 (p-values= 0.003, 0.003, 0.027), and 3 µm (p-values= 0.016, 0.032) size bins of the no waste with flush and 0.3 (p-values= 0.009, 0.007, 0.007), 0.5 (p-values= 0.018, 0.006, 0.004), 1 µm (p-values= 0.023, 0.013,) size bins of the fecal waste with flush conditions. Bioaerosol concentrations measured in the no waste no flush and fecal waste with flush were found to be significantly different (p-value= 0.005). However, the bioaerosol concentrations measured were not significantly different across time (p-value= 0.977) or distance (p-value= 0.911). From the study, we concluded that toilets in this unit produce particles when flushed. The particles aerosolized include microorganisms remaining from previous use or from loose fecal wastes. Differences in bioaerosol concentrations across conditions also suggest that toilets flushed containing wastes may be a likely source of bioaerosols that could allow transmission of infectious microorganisms. No observed differences across time and distance of bioaerosol concentrations suggests that generated aerosols quickly diffuse in the air. Since this study is the first to quantify particles and bioaerosols produced from flushing a hospital toilet, future studies are needed for comparison and for intervention development.

Musculoskeletal disorders (MSDs) are common among working populations, especially manufacturing workers, with exposure to non-neutral postures frequently cited as a risk factor. However, the magnitudes and precision of risk estimates vary between field-based studies, as it is difficult to continually follow and sample large study samples with time-varying exposures to non-neutral postures. Development of a low cost location-tracking system may help overcome this methodological limitation. The purpose of this thesis was to explore the utility of radio frequency identification (RFID) technology for extracting task-specific exposure data from full-shift measurements of upper arm posture as machine-paced assembly workers rotated job tasks. Full-shift upper arm posture and movement velocities were recorded using inertial measurement units (IMUs) across up to 15 consecutive working days from among a sample of 8 participants. Workers scanned RFID tags with RFID readers at job task workstation as they started and finished performing a task, effectively measuring task duration. At the end of each shift, workers self-reported task duration estimates in a diary. Self-report and RFID-based measurement bias and agreement range were estimated using Bland-Altman analyses. Fully nested, random-effects analysis of variance (ANOVA) models were used to estimate the relative contribution of components of exposure variance to overall posture and movement exposure variance. The study observed a slight measurement bias for self-reported task duration estimates when comparing both incomplete (i.e., single measurement from either self-report or RFID methodology) and complete task observation data (i.e., measurements from both methodologies), while the RFID system displayed a similar bias when comparing only complete task observation data. However, regardless of the data set, a large measurement agreement range was observed. The between-subjects and between-tasks-within-day (and within-subject) variance components generally contributed the most to total exposure variance, with the between-day-within-subject component contributing little if nothing at all. Depending on velocity level summary measure, between 65.7% and 84.5% of the total exposure variance was associated with the between-tasks-within-day (and within-subject) component. The RFID system did prove useful in extracting task-specific exposure data from full-day IMU measurements. However, there were unexpected instances in which workers failed to follow RFID system user protocol and generate irregular timestamp sequences. Future research and development is encouraged to refine the pairing of RFID technology with IMUs for ergonomic exposure assessment. Specifically, an active RFID system with adjustable read range could potentially overcome the limitation of requiring that a worker place the RFID tag within inches of the low frequency RFID reader to perform a scan.

Workplace aerosol sampling has been used to assess exposure to airborne materials that are known to cause adverse health effects in the respiratory system. Respirable cyclones are a common instrument used to monitor occupational exposures to respirable particles and are designed to have a penetration similar to the definition for the respirable fraction. However, deposited particles inside the walls of the cyclone may influence the penetration of cyclones. The aim of this study was to determine if there is a difference in collection efficiencies of a clean SKC 37-mm aluminum cyclone compared to a SKC 37-mm aluminum cyclone deposited with polydispersed dust. Glass beads (Count Median Diameter CMD 3.3 µm, Geometric Standard Deviation GSD 1.7) were used to test a clean cyclone. The cyclone was then loaded by sampling with one of three dust types individually for three hours at concentrations of at least 3 mg/m3: Arizona Road Dust (CMD 1.04 µm, GSD 1.57), organic dust (CMD 2.90 µm, GSD 1.77), and titanium oxide (CMD 0.85 µm, GSD 1.28). After the cyclone was deposited with dust without cleaning, glass beads were used to retest the penetration. Particle penetration was measured using the Aerosol Particle Sizer (APS, TSI 3321). Particles depositing on the walls of the cyclone caused a shift in the penetration compared to clean samplers. When the cyclone was loaded with Arizona Road Dust, the penetration of particles increased as much as 5% at 3.5 µm. Depositing with Organic Dust increased particle penetration as much as 4% at 3.5 µm. Depositing did not occur with Titanium Oxide and did not significantly particle penetration. Sampling with cyclones deposited with polydispersed particles can cause sampling errors by oversampling, and therefore overestimate the respirable concentration relative to a clean sampler. To counteract sampling errors from deposited particles would require the cyclone to be thoroughly dried and clean before sampling.

The objective of this study was to assess the utility of electron microscopy for the purpose of distinguishing engineered nanoparticles from "incidental" nanoparticles. Methods included the use of transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS) to analyze samples of known ratios of titanium dioxide (TiO2) to Arizona road dust (ARD) or incense particles. TEM collection methods were analyzed for two different samplers: a Marple impactor and an electro-static precipitator (ESP). TEM grids were placed on the four lowest stages of the impactor. Results for impactor stages of a 10:1 ratio of TiO2/ARD mixture displayed the following percentages TiO2: 44%, 44%, 83%, and 90%. TiO2/incense samples had very high (79%-90%) TiO2 proportions, which was not expected since the ratio was 1:1. These combustion particles did not collect with the same efficiency as TiO2 or ARD. In conclusion, incense particles were entirely carbon based and were not identifiable using TEM/EDS. The TiO2/ARD mixture demonstrated that the impactor would remove most of the larger particles so that grids on the filter stage could be used to analyze and image TiO2 mostly alone. Sampling criteria for desired particle loading had to be established in order to obtain usable TEM grids. TiO2 was distinguishable from all other particles, but accurate particle identity and proportion in samples was not obtainable for combustion particles using these methods.

Field portable x-ray fluorescence (FPXRF) was evaluated as a method for screening titanium dioxide (TiO2) on air filters. Mixed cellulose ester (MCE) and polycarbonate (PC) filter types were compared to gravimetric filters to determine if there was a benefit of using one over the other during FPXRF analysis. No significant difference (p-value = 0.92) was found between MCE and PC filters for FPXRF. MCE filters had a higher coefficient of determination (R2 = 0.97) with the FPXRF analyzer than the PC filters (R2 = 0.70) when compared to gravimetric filter results. The limit of detection (LOD) and limit of quantitation (LOQ) of the FPXRF analyzer were determined through the analysis of blank filters and filters with low levels of TiO2 analyte. The LOD for TiO2 using filter blanks was 7.3 μg/filter, and 25 μg/filter with low levels of TiO2 analyte. The LOQ was 12.8 μg/filter determined with filter blanks, and from the low level analyte samples was 0.82 μg/filter. Filter samples were collected at varying TiO2 concentrations and submitted to FPXRF and inductively couple plasma - mass spectrometry (ICP-MS) analysis. Linear regression was used to determine the relationship between the two methods for TiO2 assessment. A high coefficient of determination (R2 = 0.90) was found between FPXRF and ICP-MS at lower TiO2 concentrations while a low coefficient of determination (R2 = 0.24) was shown for the high TiO2 concentrations. Statistical analysis was used to determine the overall accuracy of the FPXRF method. The FPXRF method did not meet the NIOSH accuracy requirements to be considered an acceptable method; however there were unexplained anomalies within the ICP-MS data.