Swine workers in concentrated animal feeding operations (CAFOs) are at risk of developing respiratory illnesses as a result of exposure to a combination of ammonia (NH3), carbon dioxide (CO2), and dust. The purpose of this study was to determine whether the use of a recirculating ventilation system with a filter-type air pollution control (APC) unit (Shaker Dust Collector, United Air Specialists Inc.), selected to control dust, would inadvertently increase NH3 and CO2 concentrations in a farrowing room. During the 2013-14 winter season, NH3 and CO2 concentrations were measured at six fixed locations throughout the farrowing room test site. Direct reading instruments (NH3: VRAE, Rae Systems Inc.; CO2: ToxiRAE Pro, Rae Systems Inc.) were deployed for 24-hour periods throughout the season on 18 randomly selected days. Contaminant concentrations were measured and compared by ventilation status (APC ON: 11 days, APC OFF: 7 days). Ammonia concentrations were above the literature recommended limit (7 ppm) on 13 of the 18 sample days (72%) and even exceeded the threshold limit value (TLV) of 25 ppm on one of the sample days. Carbon dioxide concentrations exceeded the literature recommended limit of 1540 ppm on all 18 sample days, and average concentrations were half of the TLV (2500 ppm). There was no statistically significant difference in NH3 (p > 0.23) or CO2 (p > 0.67) when concentrations were compared by APC status. The results of this study indicate a recirculating ventilation system with filter dust control does not increase NH3 or CO2 concentrations spatially or temporally in the room during operation. Future work will investigate engineering control options to reduce CO2 concentrations in the farrowing room.

The research presented in this doctoral dissertation strived to increase knowledge with respect to respirators performance in the workplace by evaluating particle penetration and breathing resistance (BR) of N95 filtering face-piece respirators (FFRs) under simulated air environmental conditions, determining maximum particle penetration of uncertified dust masks (UDMs) against sodium chloride (NaCl) and BR of UDMs and FFRs when challenged against Arizona road dust (ARD), and evaluating BR of FFRs while performing power washing in swine rooms. A novel test system was used to measure particle penetration and BR of two N95 FFRs under modified environmental conditions. NaCl particle penetration through the FFR was measured before and after the BR test using a scanning mobility particle sizer. BR of the FFR was measured by mimicking inhalation and exhalation breathing, while relative humidity and temperature were modified. BR was evaluated for 120 min under cyclic flow and four temperature and relative humidity air conditions. The BR of the FFRs was found to increase significantly with increasing relative humidity and lowering temperature upstream the FFR (p < 0.001). Measured particle penetration was not influenced by the simulated air environmental conditions. Differences in BR was observed between FFRs indicating that FFRs filtering media may perform differently under high relative humidity in air. In the second study, the maximum particle penetration of five commercially available UDMs was evaluated against NaCl aerosol. Particle penetration was carried out as specified by National Institute for Occupational Safety and Health (NIOSH) to certify N95 FFRs (42 CFR Part 84). Particle penetration was found to vary between 3% and 75% at the most penetrating particle size. In addition, the effect of mass loading on BR of UDMs and FFRs over time was evaluated. ARD was used as the loading dust and BR was measured for 120 min on UDMs and FFRs. BR was found to increase differently between the tested UDMs and FFRs. Further analysis of the UDMs and FFRs external layer suggest that the development of the particle dust cake during mass loading may be influenced by differences of the external layer. In the third study, field research was conducted to evaluate BR of two N95 FFRs while performing power washing in swine rooms. A member of the research team wore the FFR while power washing swine rooms. Every 30 min the team member stopped power washing, BR was measured and power washing continued. At the end of the 120 min trial, the FFR model was switched and the team member continued to power wash the rest of the room. Results demonstrated that BR of the tested FFRs did not increased during power washing in swine rooms (FFR 1, p = 0.40; FFR 2, p = 0.86). Power washing was found to have an effect in the temperature and relative humidity inside the rooms. Based on this study, FFR wearer should expect no increase in BR over 8 hr of power washing, decrease health risk by wearing the FFR and no need to replace the FFR during the power washing task.

Dissertation submitted to the faculty of Health Sciences at the Durban University of Technology in partial compliance with the requirements for a Master's Degree in Technology: Chiropractic, 2007. / The objectives of this study were: To determine how the frequency of manual work contributes to low back pain in nurses in state versus private hospitals in the Durban area. To determine how the frequency of manual work contributes to low back pain in nurses in state versus private hospitals in the Durban area. Hospital nurses have a high prevalence of low back pain (LBP) (Smedley et al., 2003). It has been found that nursing personnel ranked fifth in occupations claiming worker compensation for low back injuries (Owen and Garg, 1994). A number of studies have also indicated a strong association between musculoskeletal disorders and work related factors (Maul, 2002). An epidemiological study by Smedley et al (1997) has suggested that repetitive lifting, frequent bending and twisting play a role in the development of LBP, and that heavy physical workload has played a major role in the development of LBP in nurses. LBP is therefore a serious problem in the nursing field with a relatively high prevalence worldwide. It causes increased absenteeism from work and could impact on patient care. This study was a survey, which was quantitative in nature. Data was collected by means of a questionnaire. The questionnaires were handed out in randomly selected hospitals in the Durban Metropolitan area. The names of all state and private hospitals in the Durban Metropolitan area were put into two boxes and three names were picked from each box. A letter requesting permission to carry out this research was sent out to each hospital and a positive response was received from one state hospital, R.K Khan Hospital and two private hospitals, Westville and Entabeni hospitals. Questionnaires were handed out to the nurses by the researcher, as requested by the hospitals, and collected at a later time by the researcher. Questionnaires were handed out at each ward in the hospitals to nurses who met the criteria for the study and agreed to participate in this study. Questionnaires were also handed out to nurses in the nurses lounge during lunch breaks. The questionnaire was developed as combination of; a pre-validated questionnaire made available by Yip (2001), questions on socio-demographic data, work history, patient handling activities and LBP. The compiled questionnaire was tested for face and construct validity through a focus group, and piloted before being used in the study. A total of 500 questionnaires were handed, 250 to state hospitals and 250 to private hospitals. Participants consisted of nurses (registered, enrolled and student) between the ages of 18 and 45 years, both male and female. Nurses from all hospital wards were allowed to participate in this study. A total of 124 questionnaires were received back, ( 50 from private hospitals and 74 from the state hospital), from the nurses in all the hospitals. Data was then collected from these questionnaires and was analysed using the statistical package SPSS version 13 (SPSS Inc. Chicago, Illinois, USA). A p value of <0.05 was considered as significant. The data collected from the questionnaires was analysed and the results obtained were as follows: The prevalence of work related LBP in this study was 59.7%. Of the 74 nurses with LBP, only 7 (9.5%) reported having LBP before working as a nurse. 35.1% of participants reported that they experienced pain on a daily basis while 62.2% described their LBP as moderate and 27% described their pain as severe. The median duration of LBP was 3.5hours per episode. Of all the participants in this study, 64,9% had needed bed rest due to their LBP with 43.2% having taken sick leave from work for LBP. Back pain in nurses has been found to be a major cause of days lost due to sickness (French et al., 1997). The majority of nurses (93.2%) reported lifting to be the cause of their LBP, standing and bending were also found to be important causes. Low Back injury was reported in 31.1% of participants with up to 51.4% receiving treatment for their injuries, the main choice of treatment was from a hospital or General practitioner. With regards to the frequency of manual work on LBP, there was found to be a slight tendency toward LBP with more frequent manual activity, however this was viii found to be non significant. In those respondents with LBP, the activity associated with the most intense LBP was carrying or lifting patients. Time spent; standing, holding up hands and bending were found to be higher in the group which reported LBP. Having 1-2 children was also associated with increased LBP. The prevalence of LBP was found to be higher in the state hospital (67.6%) than in the private hospitals (48%). The aim of this study was to determine the association between frequency and intensity of manual work on LBP in nurses. The results showed that frequently performed manual activities were associated with LBP but not significantly. In terms of intensity of manual work, carrying or lifting patients was found to be most associated with LBP, standing and bending were also significantly associated with LBP. This study also aimed to determine any difference in LBP between state and private hospitals and a significant difference in LBP prevalence was noted between state and private hospitals. The findings of this study suggest that LBP is a common problem among hospital nurses. The results of this study were also found to be within the same prevalence rates of international studies, which ranged from 35.9% in New Zealand to 66.8% in the Netherlands (Nelson et al., 2003). As was found in the literature (French et al., 1997 and Smedley et al., 1997), lifting was reported to be a major cause of LBP.

Dissertation submitted in partial compliance with the requirements for the Masters Degree in Technology: Chiropractic, Durban Institute of Technology, 2005. / Emergency medical personnel have a number of occupational risk factors that are listed in the reviewed literature (Davis and Heaney 2000, Volinn 1997 and Andersson 1999) as risk factors for low back pain. Physical lifting and carrying of patients and equipment increases stress on the lower back, while occupational stress and a high level of patient responsibility are mental risk factors (Davis and Heaney, 2000). Emergency medical personnel that spend long hours in response vehicles, ambulances or helicopters are exposed to vibrational stressors and may therefore have an increased risk of low back pain due to this whole body vibration (Palmer et al, 2000). In addition it has been noted that the number of motor vehicle accidents will also increase the risk of low back pain due to mechanical injury (Cassidy et al, 2003). Low back pain could therefore interfere with their ability to carry out their duties, affect their attitude towards patients and colleagues, impact on the level of patient care required of them, and result in increased absenteeism. Persistence of chronic low back with the inability to perform their duties may result in the need to find alternative employment or result in premature dismissal. The objectives of this study were: to determine if emergency medical personnel have a higher risk factor for the development of low back pain due to their occupation than the general population; as well as determine if an increase in the number of years working in the field (i.e. years of exposure) leads to an increased incidence and / or prevalence of low back pain. / M

Hydrogen sulfide (H2S) is a gas commonly produced in manure pits. When the manure is disturbed through manure handling activities such as pressure washing, agitating, and pumping out manure, H2S is released. During these activities H2S concentrations increase quickly and reach hazardous concentrations. Many fatalities from high H2S concentrations during manure handling activities have been reported internationally as well as in the Midwest. Occupations in general industry that have identified the potential for high H2S concentrations use monitors to warn worker of high H2S concentrations. However, in agriculture the adoption of H2S monitors is low. To encourage farmers to adopt H2S monitors, interactive training materials were created. Displays were deployed to locations that farmers frequent such as agricultural stores, extension offices, and cooperatives. Agricultural stores are defined here as locations that sell agricultural supplies wholesale, or retail, and services. These displays contained educational materials, two H2S monitors, and two types of bump testing gas for farmers to use. Along with the display passive trainings, six in-person trainings were completed where participants filled out surveys. The survey asked questions about the farmers knowledge and use of H2S monitors, likelihood of purchasing a H2S monitor in the future, easiest bump testing gas to use and the one preferred for future bump testing, and the location that farmers would prefer to go to for bump testing and monitor education. Survey participants were placed into two groups: livestock producers and commercial manure applicators. A total of 43 surveys were completed by these groups. The majority of both livestock producers and commercial manure applicators knew what H2S monitors were, but less than half of the participants actually used H2S monitors. Outreach focusing on H2S monitor use and maintenance should be continued. Hydrogen sulfide monitor use and maintenance training had the more attendance when added to an already existing training or meeting such as the manure applicator trainings or livestock producer meetings. In the survey, livestock producers and commercial manure applicators were asked the easiest type of bump testing gas where both groups chose that the calibration gas is easiest to use. When prices were included in the survey question for both bump testing gas systems, many more of livestock producers and commercial manure applicators responded that they could see themselves using neither in the future. Price of bump testing systems ($130-$220) can be a potential barrier for some farmers to not bump test their monitors, it would be beneficial for multiple farmers to share one bump testing system. Putting a bump testing system in at agricultural stores, cooperatives and extension offices would allow many farmers to use it. Commercial manure applicators reported that they had no preference in future locations for bump testing and monitor advice between the agricultural store, cooperatives, and extension offices. Livestock producers preferred agricultural stores a little more than cooperatives and extension offices, but all three locations should be used for continuing H2S monitor education. In our study agricultural stores had the most bump tests recorded, bump testing gas used, they purchased a bump testing system for their customers.

Norovirus is the most common pathogen to cause acute gastroenteritis in the world. Symptoms of acute gastroenteritis include vomiting and/or diarrhea, along with fever, abdominal pain, and malaise. Annually, norovirus causes 685 million cases of acute gastroenteritis and 200,000 deaths, worldwide. Among the 685 million cases occurring every year, 19-21 million occur in the United States. Norovirus can spread through direct or indirect contact (e.g., contaminated food or water). In addition, recent evidence has suggested that norovirus can also be spread via aerosolization. However, no study has determined an indoor generation source for aerosolized norovirus. Therefore, the goals of this study were to optimize sampling and quantification methods for the collection of aerosolized norovirus. Upon optimization, the last was to investigate a potential indoor generation source (i.e., toilet flushing) of aerosolized norovirus. To achieve this goal we devised three studies. In the first study, we optimized a sampling method for the collection of aerosolized norovirus using murine norovirus (MNV) as a surrogate. Optimization of the sampling method was performed using two bioaerosol samplers (SKC BioSampler and the National Institute for Occupational Safety and Health [NIOSH] Bioaerosol Cyclone Sampler 251) and two sampling media (Hanks Balanced Salt Solution [HBSS] and Phosphate Buffered Saline [PBS]). Murine norovirus was aerosolized in a bioaerosol chamber and later collected using the optimized sampler/media combination. After collection, viral RNA was extracted from MNV collected samples and quantified using quantitative polymerase chain reaction (qPCR). Intact capsids of MNV were assessed using propidium monoazide dye in combination with qPCR and confirmed with transmission electron microscopy. There were a total of 10 trials conducted, with each trial lasting for 30 minutes. The SKC BioSampler collected a significantly higher concentration of MNV than the NIOSH-251 sampler did (p-value < 0.0001). However, there were no significant differences in the relative percent of MNV that remained viable between both samplers (p-value = 0.2215). The use of HBSS sampling media yielded a higher concentration of MNV than PBS media (p-value = 0.0125). However, PBS media maintained viability at a significantly higher percentage than HBSS media (p-value < 0.0001). The results support the optimization of a sampling method for the collection of aerosolized MNV and possibly norovirus in different sampling environments. In the second study, we optimized the quantification method for MNV. A relatively new quantification system, droplet digital polymerase chain reaction (ddPCR), was evaluated using the same extracted samples collected in the first study to determine if the same overall outcome could be achieved. In addition, a MNV standard was directly compared between the qPCR and ddPCR. When comparing the same standard, the mean observed concentrations were similar to the nominal concentration. The limit of detection for both instruments was 5 copies per reaction. The coefficient of variation was lower across all ddPCR results than the qPCR results. The range of the R2 was larger for ddPCR compared to qPCR. As for the analysis of bioaerosol samples collected from the first study, the SKC BioSampler collected a significantly higher concentration of MNV compared to the NIOSH-251 sampler (p-value = 0.0002). However, there were no significant differences in the relative percent of MNV that remained viable in both samplers (p-value = 0.6734). The use of HBSS sampling media yielded a higher concentration of MNV than PBS media (p-value = 0.0190). However, PBS media maintained viability at a significantly higher percentage than HBSS media (p-value = 0.0004). The use of ddPCR allows for a simpler workflow and fewer samples and resources. These results support that both PCR systems yield similar results and overall outcomes, thus presenting an optimized quantification method for MNV. In the third study, we used the optimized sampling and quantification methods to conduct a field trial investigation of a potential indoor aerosolization source for norovirus (toilet flushing). To inform bioaerosol sampler placement, two optical particle counters monitored particle size and number distribution of aerosol produced from flushing a toilet across three variables (height, position, and side). The location with the highest mean particle concentration, and where bioaerosol sampling occurred, was behind the toilet and 0.15 m above the toilet bowl rim. A flushometer type toilet was seeded with 105 and 106 PFU/mL of MNV and then flushed. Upon flushing, a SKC BioSampler and Coriolis µ sampler were activated to collect aerosolized MNV. Samples were extracted and then quantified using RT-ddPCR, and viability was quantified using PMA: RT-ddPCR. The concentration of MNV collected after seeding the toilet water ranged from 2.18 x 105 – 9.65 x 106 total copies of MNV. Positive samples of airborne MNV were detected using the Coriolis µ sampler with collected concentrations ranging from 383 – 684 RNA copies/m3 of air. Sample viability for bioaerosol samples were unable to be quantified. The relative percent of MNV virions that remained intact in seeded toilet water was 37-79%. This study provides the first evidence that MNV, a NV surrogate, can be aerosolized when a toilet is flushed.

This research focuses on occupational exposures associated with Methicillin-resistant Staphylococcus aureus (MRSA) in modern pork production facilities. This dissertation is composed of three related parts. In Chapter II, "Methicillin-resistant Staphylococcus aureus in pork production shower facilities" we documented the presence of MRSA in shower facilities of conventional swine production systems where pigs were colonized with MRSA. We tested farms involved in different production phases (sow, nursery, and finisher) and geographical locations. In the two swine production systems studied, 3% and 26% of shower samples were positive for MRSA. Overall, the prevalence in showers was 19%. In Chapter III, "Methicillin-resistant Staphylococcus aureus in pork production shower facilities: Adapting interventions from athletic facilities," we searched the literature for interventions designed to decrease MRSA infections in athletes. We then evaluated these interventions for adaptability to the pork production environment, and composed swine-specific guidelines for MRSA prevention. We implemented our intervention in a pilot study to reduce MRSA in showers and locker rooms and results were mixed. We recommend repeating this study with a larger sample, and better intervention management and oversight. In Chapter IV, "Methicillin-resistant Staphylococcus aureus infection in pork production workers," we sought to determine if pork producers report veterinarian-diagnosed antibiotic-resistant skin infections in pigs, and physician-diagnosed antibiotic-resistant skin infections in workers (including MRSA). We then examined potential risk factors for infection associated with biosecurity, including shower and laundry procedures, farm-specific clothing use (clothing worn only while working on the farm), and personal hygiene. No significant risk factors were identified for either skin infections in pigs or skin infections in workers. These studies provide evidence that MRSA can be found in pork production shower facilities, and that occupational exposures occur due to components of the biosecurity protocol. We designed and implemented an intervention to decrease the level of MRSA in showers. Our pilot intervention suggested that the impact of showers as environmental reservoirs can be reduced. We also reported the first prevalence estimate of MRSA infection in pork production workers in the United States. Livestock-associated MRSA remains an emerging issue and requires further study to determine the true occupational and public health risks.

Exposure to noise in hospital intensive care units (ICUs) can disrupt patients’ sleep and delay their recovery. In this intervention study, noise levels were measured in eight patient rooms of a medical ICU (MICU) every minute with sound level meters for eight weeks before and after an intervention. Implemented over six weeks, the intervention was designed to educate nurses and other staff members to reduce noise levels through behavior modification, including instituting a “quiet time” in the afternoons, encouraging patients to keep televisions off or at lower volumes, and speaking more quietly during conversations. Sound equivalent levels (Leq) were calculated from one-minute measurements for each hour in each room. These hourly Leq (Leq-H) values were compared by pod (group of rooms within the MICU), room position (in proximity to a central nurses’ station), occupancy status, and time of day. Days with more than ten hours of one-minute noise levels above 60 dBA were flagged as the loudest time periods and compared to MICU activity logs. The intervention was ineffective with Leq-H values always above World Health Organization guidelines for ICUs (35 dBA in day; 30 dBA at night) before and after the intervention. Leq-H values frequently exceeded more modest project goals during the day regardless of the intervention (50% of Leq-H > 55 dBA both pre- and post-intervention) and at night (68% and 62% of Leq-H > 50 dBA pre- and post-intervention). Statistical analysis of the Leq-H suggests a general source is contributing to the high baseline noise in the MICU, most likely the heating, ventilation, and air-conditioning (HVAC) system. Our analysis of one-minute data indicated that high noise was often associated with high-volume respiratory-support devices. We concluded that our intervention focusing on administrative controls (e.g., education and training) was not enough to reduce noise in the MICU but that an intervention designed with engineering controls (e.g., shielding, substitution) would be more effective.

Previous research evaluating restaurant worker exposure used environmental sound levels, but this does not take into account the temporal variability of restaurant worker exposure. To determine the actual personal exposure of restaurant workers, Quest Noise-Pro or Quest Edge dosimeters were placed on restaurant workers at six downtown Iowa City restaurants. At each participating locally-owned restaurant, workers classified as cooks, counter attendants, bartenders, and waiters participated. A time-weighted average (TWA) exposure per participant per shift was computed using both OSHA and NIOSH criteria for a total of 180 full-shift exposure measurements. Exposures were evaluated by season (when school is in session or not), restaurant type (counter service versus sit-down with bar), job title (cooks versus others), and time of week (weekday versus weekend) to characterize factors associated with high personal noise exposures. This work focused on day time exposures of restaurant employees in locally owned restaurants in a college town and determined the risks of noise induced hearing loss (NIHL). The results determined if restaurant workers are exposed to hazardous noise and whether exposures differ by job title, season, day of week and restaurant type. No TWA measurements exceeded the OSHA 8-hr TWA permissible exposure limit (PEL) of 90 dBA. Restaurant worker NIOSH TWAs ranged from 69-90 dBA with a mean (SD) of 80 dBA (4 dBA). Only 7.8% of all full-shift exposure data exceeded the NIOSH 8-hour 85 dBA. The highest worker TWAs were recorded during the period when the local university was in session and at the full-service restaurants: these workers were cooks during the weekends. Fourteen TWA measurements exceeded the NIOSH 8-hr TWA REL of 85 dBA. The NIOSH TWA exposure estimates significantly increased for full-service restaurants (p<0.001), cooks (p=0.003), during the fall semester (p=0.003), and during the weekend (p=0.048). Multiple Linear regression analysis suggested that restaurant type, job title, and season have a significant effect on restaurant worker noise exposures (p<0.001). Although restaurant employee noise exposures are within the OSHA hearing conservation standard limits, this study demonstrated that 7.8% (approximately 733,200) restaurant workers might be at risk for overexposure to noise based on NIOSH criteria. Intervention studies for the prevention of NIHL need to understand the impact of job title, restaurant type, season, and day of week on restaurant worker noise exposure. Additionally, all sampling was completed during the daytime and future research should evaluate restaurant worker noise exposures into the night time and early morning hours.

The primary goal of this PhD research was to obtain critical information needed to further calibrate the novel glass-based retrospective radon detectors (RRDs) by characterizing the quantitative relationship between radon gas concentrations, the surface-deposited activities of various radon progeny, the airborne dose rate, and various residential environmental factors through both actual field measurements and Monte-Carlo simulation. Radon and radon progeny concentrations were measured, from May 2005 to May 2007, in 38 Iowa houses occupied by either smokers or nonsmokers. The investigation took into account several important indoor environmental factors, which have crucial influences on the radon progeny deposition process in homes. The long-term (3 months) surface-deposited radon progeny by species and implanted 210Po were measured using a RRD. During the 3 months, the short-term (3-7 days) airborne radon progeny by species and bimodal size fraction were measured using a recently developed active detector. Both passive and active detectors are solid state nuclear track detectors. Airborne dose rates were calculated from unattached and attached potential alpha energy concentrations (PAECs) based on both Porstendörfer's effective dose conversion factor and that of James. Correlation analysis and multiple linear regression analysis were applied to analyze both field study results and Monte-Carlo simulation study results. Temporal and spatial variations among airborne dose rates and surface-deposited radon progeny were also investigated in actual field settings. Overall, deposited radon progeny were useful in predicting airborne dose rate in addition to the radon gas concentration. The occurrence of smoking was the most crucial environmental factor influencing the deposition process. In addition, other environmental factors were identified that served as useful covariates predicting airborne dose rates by smoking status. The results from our current study will greatly aid the future resolution of the final reanalysis of the lung cancer risks for the Iowa Radon Lung Cancer Study (IRLCS) based on radon progeny exposure estimates obtained from RRD measurements. In addition, the results of this study will be used as the basis for a large-scale pooled analysis of the Iowa and Missouri Residential Radon Studies, both of which incorporated the use of the glass-based detectors within their study designs.