1,721,075 research outputs found
Implementing Temporary LED Construction Lighting
No full textThesis (Master's)--University of Washington, 2017-06LED lighting technology is continuing to grow and change every 6 months. While other manufacturers and consumers are finding creative ways to implement them in their products and everyday life, the construction industry has yet to widely adopt and embrace the technology as a temporary lighting source on their projects. Although initially expensive when compared with other construction lighting systems, the cost of LEDs is decreasing while improvements in LED luminaire efficiency increases. Furthermore, the energy, maintenance, and safety benefits of a temporary LED lighting system may be an overlooked consideration for general contractors and subcontractors as (1) the information has yet to be thoroughly studied and targeted at the construction industry, (2) initial costs of entry may be prohibitive when compared with older sources of luminance, and/or (3) general contractors and subcontractors may be satisfied with the status quo. Unfortunately, improvements in temporary lighting technology for building construction have been neglected academically and within the construction industry. However, the objective of this thesis is to serve as a guide by looking at the safety, energy and maintenance benefits of LED construction lighting, through literature review, lessons learned from two case studies, and independent investigation by the author. Literature review will provide a background on how LEDs work, what traditional lighting is, who regulates quality of luminance on jobsites, and how lighting affects the safety and health of workers. 2 Next, the thesis incorporates two case studies, both of which were conducted at the behest of the University of Washington’s (UW) Capital Planning and Development office (CPD). The first case study was generated in 2014. The study, written by UW Construction Management graduate student Yi Jie Huang, focused on the temporary construction lighting at the UW’s Bothell Phase 3 Project. The report looks at: (1) the system’s installation method; (2) labor, material, and energy cost; (3) stakeholder interviews; and (4) a qualitative survey of the workers. The second case study, written by UW Construction Management and Occupational Safety and Health graduate student Christopher Mak, further updates the UW’s narrative on LED lighting, and illustrates the history and reasoning behind implementing low-voltage LEDs on their projects. The report homes in on the LED utilization at the UW’s Animal Research and Care Facility (ARCF) construction site. Like the report on the Bothell Phase 3 project, the second case study looks at: (1) installation method; (2) labor, material, and energy costs; and (3) conducts a qualitative survey of workers. Finally, the author ran three quantitative studies looking at light levels, energy use, and lighting quality. Data collected is displayed and interpreted within. The final issue the author looks at is the possibility of glare, which arose during qualitative data analysis of both case studies’ responses. Glare emanating from white LEDs is a potential safety hazard and an environmental quality problem. Moreover, defining hazardous amounts of glare can be subjective and hard to quantify. The author implements a glare quantifying methodology using HDR photography, and uses the technique to gauge the quality of light emanating from ARCF’s new LEDs. The thesis concludes with lessons learned regarding how users can better implement temporary LED lighting to their full benefit from the trials and tribulations experienced by the UW, observations made by the author, and from the Seattle City Light inspection and energy incentive process
Evaluation of the Impact of Indoor Air Filtration on Particulate Matter Exposures and Measures of Cardiovascular Health
No full textThesis (Master's)--University of Washington, 2019Background: The efficacy of the high-efficiency particle arresting (HEPA) air cleaner and its related health benefits have gotten some attention, yet the number of studies on this topic is still modest. Recently, a commercially-available “auto-mode” air cleaner has emerged on the market that adjusts the operating fan speed automatically depending on its built-in particulate matter (PM) sensor, which may improve real-world effectiveness since it doesn't rely on the user to adjust the air cleaner when they perceive the air is polluted. Objectives: We sought to assess the impact of auto-mode filtration on indoor PM exposure and cardiovascular health among healthy, non-smoking adults in an urban United States location. Methods: The study approach was a randomized, crossover 3-way air filtration intervention pilot study in the urban Seattle area from February 1 to March 29, 2019. Six non-smoking, healthy young adults were enrolled in the study, provided an air cleaner, and exposed to each of the three following intervention scenarios for 1 week (order of interventions randomized), with each one separated by a washout period of at least two weeks in duration: (1) a control period consisting of a sham filter installed in the air cleaner, (2) an intervention consisting of the air cleaner set to auto-mode filtration, and (3) an intervention in which participants were allowed to adjust the settings of the air cleaner. In all cases, the air cleaner was used in the participant’s living room. Participants were asked to take two blood pressure measurements daily at 8 am and 8 pm. Indoor area PM2.5 monitoring was conducted in both the kitchen and the living room of each household using a continuous particle counter. Results: The indoor mean PM2.5 levels measured in the living room and the kitchen were significantly reduced by 5.05 µg/m3 (95% CI [-6.19, -3.91]; p<0.001) and 6.60 µg/m3 (95% CI [-7.86, -5.34]; p<0.001) , respectively under the auto-mode filtration compared to the sham-mode filtration; whereas under the adjustable-mode filtration, the indoor PM2.5 level was significantly decreased by 3.43 µg/m3 (95% CI [-4.57, -2.28]; p<0.001) and 5.01 µg/m3 (95% CI [-6.27, -3.76]; p<0.001) in the living room and kitchen, respectively, compared to sham-mode filtration. Auto-mode filtration significantly reduced the indoor mean PM2.5 levels in the living room and the kitchen by 1.63 µg/m3 (95% CI [-2.76, -0.48]; p=0.01) and 1.59 µg/m3 (95% CI [-2.84, -0.34]; p=0.04), respectively, compared to adjustable-mode filtration. 12-hour personal exposure, which accounted for time-activity patterns and exposures away from home, was reduced by 5.45 µg/m3 (95% CI [-9.51,-1.39]; p=0.01) under the auto-mode filtration and 4.26 µg/m3 (95% CI [-8.37, -0.14]; p<0.05) under the adjustable-mode filtration, compared to sham-mode. Auto-mode reduced the 12-hour personal exposure by 1.19 µg/m3 (95% CI [-6.11, 3.73]; p=0.8), compared to adjustable-mode filtration. A near statistically significant decrease in morning systolic blood pressure of 6.1 mm-Hg (95% CI [-12.5, 0.3]; p=0.06) was found under the auto-mode filtration compared to sham-mode. Conclusions: Results of this study indicated that using HEPA auto-mode filtration resulted in higher reductions in indoor PM2.5 level and personal PM2.5 exposures. Using an auto-mode air cleaner may lead to real-world effectiveness for reducing indoor PM2.5 exposure. The findings on morning blood pressure are suggestive that auto-mode filtration may improve cardiovascular health
Investigate Woodsmoke and Interventions in an Exposure Chamber: A Tent Project
No full textThesis (Master's)--University of Washington, 2022Background: Particulate matter (PM)-related health effects have been studied extensively, yet wildfire smoke-specific PM health effects and its dose-response relationship have not reached a consensus due to variations in exposure scenarios and health outcome measurements. Additionally, researchers have not tested the wildfire smoke PM intervention strategies, especially HEPA (high-efficiency particulate air)-filter portable air cleaners (PACs) and HEPA-installed powered air-purifying respirators (PAPRs), for their particle removal efficiency and effectiveness in a laboratory setting. Objectives: This research was dedicated to designing and engineering an exposure system that can be generalized, repeated, adjustable, and easily accessed by future controlled wildfire smoke human exposure studies. Woodsmoke particle size distribution and composition from different sources were investigated and we also tested woodsmoke particle removal efficiency and effectiveness of HEPA-filter PACs and the HEPA-installed PAPR system. Methods: A total of 15 experimental trials were conducted to test and trial-run the exposure system with different sources of woodsmoke generation. Woodsmoke particles were introduced from the generation sources to the mixing chamber, and eventually to the exposure chamber where we monitored the particle concentrations and size distribution with low-cost and research-grade instruments. We assessed the woodsmoke particle composition using an aethalometer and monitored the CO and CO2 levels using a gas monitor. In addition, HEPA-filter PAC woodsmoke particle removal efficiency and HEPA-installed PAPR particle removal effectiveness were tested in two of the experimental trials, separately, with woodsmoke particles introduced into the exposure chamber. Results: With time series on the particle mass and count concentration plots, we demonstrated the ability to relatively tightly control the woodsmoke particle concentrations (50 μg/m3 and 90 μg/m3) inside the exposure chamber with both wood pellet stove and cooking smoke guns as smoke generation sources. We also observed an overall higher particle count concentration from the wood pellet stove (around 700 particles greater than 0.3 μm per cc) than the cooking smoke gun (around 500 particles greater than 0.3 μm per cc) despite the target woodsmoke particle mass concentration from the cooking smoke gun trial being higher than the wood pellet stove trial. The wood pellet stove (around 5000 particles smaller than 0.3 μm per cc) also was believed to generate more smaller particles by count than the cooking smoke gun (around 2000 particles smaller than 0.3 μm per cc) and the black carbon content was also higher in the wood pellet stove trial. In terms of the particle removal efficiency and effectiveness from PM mitigation strategies, we discovered that regardless of the HEPA filter age, when PACs were turned on at the highest speed, both new and used HEPA filters removed woodsmoke particles effectively at similar efficiency. HEPA-installed PAPR system also reduced the woodsmoke particle concentration from around 50 μg/m3 to close to 0 in less than 1 second. Conclusions: The results further proved that with further refining and engineering of the exposure system, researchers would have the opportunity to standardize their wildfire smoke controlled human exposure study protocol and migrate to an exposure system that is similar to ours. Both HEPA-filter PAC and HEPA-installed PAPR systems are efficient and effective in woodsmoke particle removal to potentially improve indoor air quality and reduce occupational wildfire smoke exposure
Using Sensors to Investigate the Effectiveness of Portable Air Filtration for Reducing Particle Exposures: Implications for Community Congregate Settings
No full textThesis (Ph.D.)--University of Washington, 2024Background: This study addresses critical aspects of indoor air quality management with a focus on community congregate settings through a combination of laboratory and field studies. We aimed to 1) Develop a standardized laboratory protocol for characterizing and calibrating the performance of low-cost optical particle sensors, 2) Evaluate the real-world effectiveness of portable HEPA air cleaners (HEPA PACs) in reducing indoor particle levels in community congregate settings, while assessing usage patterns and factors influencing their efficacy, and 3) Understand the impact of filter dust loading on HEPA PAC’s long-term performance concerning wood smoke particles. Methods: For Aim 1, we developed a standardized laboratory experimental protocol to assess the performance of a low-cost optical particle sensors against a lab-grade aerodynamic particle sizer in a controlled environment. This involved utilizing standardized polydisperse testing aerosols and developing improved calibration algorithms based on particle sizes, physical characteristics, number concentration, and mass indices. The sensor-to-sensor reproducibility was also evaluated. For Aim 2, we assessed the real-world effectiveness of HEPA PACs in reducing particle concentrations in community congregate living settings. We deployed multiple HEPA PACs in three homeless shelters in King County, Washington, and utilized low-cost optical particle sensors to measure indoor and outdoor optical particle number concentration (OPNC). Additionally, we tracked HEPA PAC usage with power data loggers and modeled its relationship to indoor/outdoor ratios of total OPNC. Post-hoc surveys were implemented to identify the challenges in HEPA PAC utilization. For Aim 3, we conducted a laboratory study to assess how filter dust loading affects HEPA PAC’s long-term performance. We pre-loaded HEPA PAC filter combinations of pre-filter, charcoal filter, and HEPA filter with varying amounts of ISO 12103-1 A2 fine test dust, simulating 1 to 11 months of continuous use at max fan speed in typical US homes. Fresh woodsmoke was used to test filter performance. We examined the relationship between filter loading and airflow rate, pressure drop, power consumption, and clean air delivery rate (CADR). Results:Results revealed discrepancies in particle size distribution between low-cost particle sensor original equipment manufacturer’s (OEM) calibration and reference aerodynamic particle sizer measurements. Calibration models demonstrated improved accuracies for number and mass concentrations, with limitations at lower concentrations and larger size bins. Additionally, evidence was found of HEPA PACs effectively reducing indoor particle concentrations, with usage patterns significantly influencing efficacy. Keeping HEPA PACs on was the main challenge to operate them in multi-zone congregate living settings. Laboratory investigations supported the use of HEPA PACs under max fan speed for up to 7 months without a significant decrease in CADR in typical US residential environment. Conclusion:This study advances indoor air quality management through laboratory experimentations and field evaluations. Our findings refine low-cost optical particle sensor calibration, underscore the efficacy of HEPA portable air cleaners (PACs) in community settings, and highlight the importance of filter maintenance for sustained performance. Through evidence-based findings, this research contributes to ongoing efforts to improve public health outcomes and indoor air quality
Using sensors to investigate the acute effect of traffic-related air pollution in different commuting modes
No full textThesis (Ph.D.)--University of Washington, 2021The contribution of transportation to ambient particulate matter (PM) has increased since 2000 in China. Over this time, Chinese cities have grown rapidly in size, population, car ownership and daily commute distance. These changes have led to increased travel times, exposures to traffic-related air pollution (TRAP) and combined uses of transportation modes during daily commutes. This dissertation aims to explore the health impacts of TRAP exposure for different commuting modes, evaluate a possible intervention to mitigate the adverse effects of TRAP in traffic, and investigate the relationships between built environment factors and travel behaviors for adults in Chengdu, China. First, portable sensors were employed to characterize TRAP and noise exposures in different transportation modes, neighborhoods and seasons in Chengdu. The study found that car trips exposed people to the lowest TRAP and noise levels compared to other modes (i.e., cycling, riding buses, and riding subways). Second, a randomized double-blind crossover intervention experiment was conducted among 21 healthy adults, where each subject travelled on a scripted route repeatedly for two hours using different transportation modes. Subjects used portable positive pressure respirators in half of the trips and wore sham respirators in the other half of the trip. TRAP exposure was recorded during each trip and cardiorespiratory health outcomes were measured immediately before and after trips. The study showed traveling by bus, subway or walking was associated with increased heart rate and decreased lung function as compared to riding in a personal motor vehicle. Increased black carbon and PM with aerodynamic diameter less than 1.0 μm (PM1) exposures were associated with elevated airway inflammation and decreased lung function, respectively. However, the study found no significant differences in cardiorespiratory health outcomes between subjects wearing effective respirators and those using sham respirators for two hours in traffic. Third, a commute survey was conducted in Chengdu to ask for home addresses, work locations and time respondents spent in multi-modal commuting. The non-linear relationships between built environment factors extracted from a Geographic Information System and time spent in different transportation modes were explored. Finally, a health impact assessment was performed for TRAP exposure and physical activity to evaluate the impact of multi-modal commuting under potential built environment changes on cardiovascular diseases mortality for employed urban residents in Chengdu. The study found that home-work distance was the most important factor in determining time spent in different travel modes. The health impact assessment showed that generally, commuting under the policy of garden city and easier access to public transit would be beneficial for cardiovascular health of residents. However, a longer home-work distance was estimated to lead to excess cardiovascular diseases mortality due to increased TRAP exposure and reduced physical active in daily commutes. Overall, these studies in Chengdu, China suggest that active and public transportation exposes commuters to higher TRAP levels. For interventions at the individual level, wearing a novel positive pressure respirator to reduce TRAP exposure during commutes may not improve the cardiorespiratory health among healthy adults. For policy interventions, the planning policy of garden city and TOD would potentially benefit population health for employed urban residents in Chengdu. However, future planning policies are needed to reduce pollutant concentrations and to address the job-housing mismatch in Chinese cities to reduce commuting distances and to protect population health
The Effect of Exposures to Aircraft Ultrafine Particles on Acute Cardiorespiratory Health, and Control Using Personal Protective Equipment
No full textThesis (Master's)--University of Washington, 2022Background: JP-8, Jet A-1, and Jet A are kerosene-based aviation fuels. Jet fuel combustion produces complex pollutant mixtures including VOCs, CO2, CO, NOx, SOx, PAHs and PM. Particles are characterized by size, with ultrafine particles (UFPs -- those particles < 100 nm in diameter) typically quantified by particle number concentration. Previous studies have reported higher concentrations of small UFPs from aircraft combustion emissions, reported as concentrations in the 5 to 40 nm in diameter range. The size distribution and concentration are dependent on the aircraft type, engine, airport, and weather conditions, suggesting that health outcomes may vary by exposure scenario. Exposures to UFPs have been associated with decreased lung function and increased airway inflammation in those with asthma, as well as oxidative stress in those who are healthy. The goal of this study was to characterize outdoor particle exposures under the flight path near Sea-Tac International Airport in SeaTac, Washington, and to demonstrate feasibility of assessing differences in short-term cardiorespiratory outcomes using crossover study design with controlled exposures and a repeated health measures design. Methods: All data for the study were collected at the SeaTac Community Center (Center) located in SeaTac, Washington. The Center is directly under the flight path of Sea-Tac International Airport, with the north end of the runways located approximately 1.5 km southwest of the site. Data collection occurred in two separate phases: Phase 1 was a preliminary exposure sampling day in October 2021 to test the study design and protocols. During this phase, a powered air purifying respirator (PAPR) was tested to ensure efficacy in removing ultrafine particles under the face shield. Phase 2, a randomized blinded crossover study of four adults, two healthy and two with well-controlled asthma, was conducted in May 2022. In the crossover study, participants walked a set path around the perimeter of the Center for 90 minutes, wearing a sham filter on one day (exposed), and a working filter (not exposed) on a different day. Repeated cardiorespiratory assessments were conducted on both days at baseline (before walk), and at resting periods 30, 60, and 90 minutes during the walk. Air monitoring instruments were used to measure NO2, BC, PM0.3 to PM10, and UFP concentrations. Noise measurements were also collected during the study. Health measurements included neuropsychological (Stroop test and Ecological Momentary Stress questionnaire), cardiological (blood pressure (BP), heart rate (HR) and heart rate variability (HRV), and respiratory (spirometry) data. Day-specific baseline-adjusted differences between exposed and non-exposed conditions were used to assess the health effects at the three time points. Results: UFPs were observed at higher concentrations in the smaller size bins, with the highest counts measured for sizes 36.5 nm and below. The particles with the greatest counts were often found in the 11.5 and 20.5 nm size range, which is typically attributed to aircraft emissions. HR, HRV, FEV1, and FVC were observed to have the biggest effects with exposure for the asthmatic group. For HR and HRV, opposite effects were found with exposure for healthy versus asthmatic groups. The healthy group’s HRV increased while the asthmatic group decreased at the 90-minute time. The healthy and asthmatic groups had increased and decreased FEV1 and FVC at the same time points, with the asthmatic group exhibiting greater effects with exposure. Conclusion: Smaller UFPs were shown to be in higher concentrations during takeoff and when landing was more frequent. Preliminary findings from the small crossover study illustrate potential differences in cardiorespiratory health effects with exposure between healthy and asthmatic with aircraft-related air pollution exposure. However, a larger study is needed to determine if these preliminary findings are robust
The Effects of Extreme Weather Exposure on People Experiencing Homelessness in Seattle
No full textThesis (Master's)--University of Washington, 2023King County, Washington currently ranks 3rd in the nation for the number of people experiencing homelessness. Amid an affordability housing crisis, the number of people experiencing homelessness continues to grow in Seattle. People in historically redlined communities of Seattle disproportionately experience homelessness because of gentrification. Resources for people experiencing homelessness, concentrated in densely populated Seattle neighborhoods, support the community’s resiliency towards inclement weather. Locally, the effects of climate change have induced an increasing amount of extreme heat, unhealthy air quality, and freezing temperature days in the past decade. Permanent congregate and emergency shelters serve as lines of defense against both mild and severe weather events. Amidst the ongoing COVID-19 pandemic, service providers have had to adapt to mitigate the impacts of a public health crisis on homeless shelters. Underrepresented and underreported, Seattle’s homeless population faces increasing health risks associated with climate exposure and infectious disease. Operators of homeless shelters also experience additive stress from environmental factors. Labor shortages, occurring during inclement weather, result in inadequate shelter availability. People are left out on the street, facing unhealthy exposure to the elements. The purpose of this study was to gain insight into the respective living and working dynamics of shelter operators and people experiencing homelessness (PEH), focusing on moments of environmental stress. Operators and PEH were interviewed to understand the compounding health disparities associated with living unsheltered in order to offer insight into the disproportionate effects of climate change on Seattle’s most underserved communities. The major findings of the study were the gaps in resources that the shelter systems endure, and the policy and operational structure that make homelessness services and programs efficacious. Attaining permanent and temporary housing solutions is dependent on an organization’s capacity to fulfill non-emergency needs for its clientele
Fine Particle (PM2.5) Composition of Indoor and Outdoor Air Samples Collected in Xuanwei County, China
No full textThesis (Master's)--University of Washington, 2015-12Indoor air pollution is a cause of many adverse health outcomes especially in developing countries where high levels of pollutants are generated by burning solid fuels for cooking and heating purposes. In China, the lung cancer rates are highest in Xuanwei County and the burning of coal in the home is thought to be a primary cause -- especially among women who are generally responsible for domestic cooking activities and have low smoking rates. Fine particulate matter (PM2.5) samples were collected in Xuanwei County during the launch of an epidemiological study investigating the relationship between birth outcomes and PM2.5 exposure in collaboration with Kunming Medical University. PM2.5 was measured in nine households across three villages for three consecutive days. At each home, two 12-hr samples (approximating daytime and nighttime periods) were collected indoor concurrently with a 24-hr outdoor measurement. Continuous fine particle sampling was also conducted indoors using a low-cost particle sensor. Samples were analyzed for total PM2.5 mass concentration and selected components (levoglucosan, 1-nitropyrene, and benzo[a] pyrene) indicative of source and potential carcinogenicity. Concentration of PM2.5 mass and selected components varied considerably between time periods sampled indoors (daytime range 25.2 – 4371 µg/m3; nighttime range 21.7 – 156 µg/m3) and between indoor and outdoor compartments (indoor range 23.4 – 2264 µg/m3; outdoor range 16.4 – 41.1 µg/m3). Continuous PM2.5 particle monitoring confirmed the episodic nature of the fine particle generation with peaks observed mainly during typical hours of cooking activities. None of the outdoor samples were above Chinese regulatory standards for ambient air quality. Several indoor concentrations of PM2.5 were well above recommended WHO guidelines and benzo[a]pyrene (BaP) concentrations were above Chinese National Criteria standards. Future studies may benefit from longitudinal sampling to assess temporal variations that may exist within households, particularly those that have choices in cooking and heating fuels
Occupational Fatigue Prediction for Entry-Level Construction Workers in Material Handling Activities Using Wearable Sensors
Get PDFThesis (Master's)--University of Washington, 2018Research on the measurement and prediction of occupational fatigue of construction workers using wearable sensors has been carried out using different types of sensor technologies and measurement variables. Previous studies have demonstrated promising results using wearable sensors for fatigue prediction, suggesting that they may have practical use as tools for the prevention of fatigue management on worksites. However, there are no clear guidelines on the type of sensors to use in fatigue management or on the relevant sensed variables. Moreover, the collection and processing of wearable sensor data should be sufficiently simple for safety professionals to use in practice. The current study aimed to address these challenges by using several of the most active wearable sensor technologies in occupational fatigue research—actigraphy and electrocardiogram (ECG) sensors—to obtain different variables from participants performing simulated construction tasks in laboratory conditions. A total of 22 participants participated in the experiment. Of these, 19 were exposed to different task workloads and completed four repetition measurements, while three participants only completed one or two experiment session(s). A total of 80 observations obtained by the experiment were used for the analysis. Stepwise logistic regression was used to identify the most appropriate and parsimonious fatigue prediction model. Among the different variables collected, heart rate variability (HRV) measurements, standard deviation of NN intervals (SDNN) and power in the low frequency range (LF) were found to be useful in predicting fatigue. Both the fast Fourier transform (FFT) and the autoregressive (AR) analysis in the frequency domain analysis methods were employed. Log transformed LF obtained by AR analysis method was found to be more suitable for daily management of worker’s fatigue, while the SDNN was useful in weekly fatigue management. This study contributes to the body of knowledge on the use of wearable technology for the management of fatigue among construction workers
- …
