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The purpose of the study was to examine home conditions, housing satisfactions, and allergen avoidance practices of people with allergic rhinitis, focusing on female patients who lived in an urban area in a hot, humid climate. The Morris and Winter theory of housing adjustment provides a theoretical base for this study. Nine hypotheses were tested to investigate interrelationships among home conditions, housing satisfaction in terms of health issues, allergen avoidance practices, and age. A sample of 41 female allergy patients aged 20 to 77 years completed a screening questionnaire and an in-depth survey questionnaire. The researcher visited their dwellings to conduct home observations and to take photos.Dust mite allergens were reported as the most common allergy triggers. Presence of cockroaches, presence of furry pets outdoors, molds in bathrooms, and molds in kitchens were the most common problematic home conditions. Open shelves, bookcases, drapes, horizontal blinds, and foam rubber pillows were the most common allergy related items found in respondents' bedrooms. Concerning health issues, the majority of the respondents were satisfied with their homes. Allergen avoidance practices were not followed regularly, particularly, using allergen-proof pillowcases and sheets, washing bedding in hot water, wearing a particle mask when vacuuming, using an exhaust fan, an air cleaner, a dehumidifier, and cockroach traps. The respondents who received suggestions from doctors were more likely to follow allergen avoidance practices than those who did not receive suggestions.The result shows a significant negative relationship between problematic home conditions and housing satisfaction in terms of health issues. A significant negative relationship between age and allergen avoidance practices was found. Older sufferers were less likely to use allergen-proof products. They also lived in older homes that were more likely to have allergy related conditions. The most common obstacles that prevented respondents from improving their homes in order to avoid allergens were cost of products, emotional attachment to pets, not having time to improve homes, and procrastination. Based on these findings, design recommendations, home maintenance recommendations, and lifestyle practice recommendations were developed. / Ph. D.

Portable ultrasonic humidifiers add moisture into room air, but they simultaneously add exposure risks of aerosolized metals from drinking water used as fill water. The inhalation exposure from emitted metals can be overlooked, and thus, co-exposure of inhalation and ingestion and co-exposure to multiple inorganic metals is investigated. The objectives of this work are: 1) predict airborne metal concentrations and particle sizes in four realistic room scenarios (33 m3 small or 72 m3 large, with varying ventilation rates from 0.2/hr -1.5/hr), and the investigated metals are arsenic, cadmium, chromium, copper, lead, and manganese; 2) characterize exposure doses and consequent risks for adults and 0.25, 1, 2.5, and 6 yr old children, when using identical drinking water ingested and as fill water, including inhalation of fine, respirable particles generated at the frequency of 8 hrs/day (equals 121.67 days/yr) and daily ingestion, under four realistic room scenarios. The risk assessment includes non-cancer [calculation of average daily dose (ADD) and hazard quotient (HQ)] and cancer risk evaluation; 3) quantify deposition fraction and deposited doses of multiple metals in human adult's and children's respiratory tract, using multi-path particle dosimetry (MPPD) model. Results show airborne-particle-bound metal concentrations increase proportionally with water metals, and a poorly ventilated room causes greater exposure. Ingestion ADDs are 2 magnitudes higher than inhalation ADD, at identical water metal concentrations and daily exposure frequency. However, in the worse-case scenario of 33 m3 small room with low air exchange rate, the consequent inhalation HQs are all greater than 1 for children and adults, except for lead, indicating significant non-cancer risks when exposed to humidifier particles under the worse-case scenario. The cancer risks for arsenic, cadmium, chromium, and lead metals reveal are greater than acceptable one case in a million population (1E-6) produced from inhalation of the humidifier emitted metal-containing particles only. The MPPD model results indicate inhaled metal-containing airborne particles deposit primarily in head and pulmonary regions, and a greater dose (unit in µg/kg body weight/day) deposits in children than adults. Inhalation of ultrasonic humidifier aerosolized metals results in additional, and potentially greater risks (indicated by HQinhalation >1, and greater deposited dose) than ingestion at the same aqueous metal concentration, especially for children. Room conditions (i.e. volume and ventilation) influence risks. Both inhalation and ingestion exposures require consideration for eliminating multiple metal exposures and health-based environmental policy making. Consumers should be aware that they may be degrading their indoor air quality by using ultrasonic humidifiers even when filling with acceptable water quality for drinking. / Doctor of Philosophy / The purpose of this work is to investigate the exposure from use of ultrasonic humidifiers filled with drinking water containing inorganic metals. Typical exposure pathway of drinking water metals is ingestion. However, inhalation of aerosolized metals can cause undesirable health effects towards metal exposure, when fill water of ultrasonic humidifiers is the same drinking water, and the inhalation of aerosolized metals exposure pathway can be overlooked. Emitted airborne particles are composed of soluble metals in drinking water, and are respirable with diameters between 100-200 nm. PM2.5 (particulate matter with aerodynamic under 2.5 µm) concentrations increase from approximately 2 µg/m3 to hundreds of µg/m3 in a common-sized room, exceeding the USEPA's regulatory level of 15 µg/m3 for ambient air PM2.5. The resulting air metal concentrations increase with increasing metals in the fill water, and/or lower ventilation rates in a household room. In addition, children receive greater average daily exposure doses than adults (i.e. average daily dose and deposited dose, in unit of µg/kg body weight/day), when assuming daily inhalation exposure of 8 hr/day and daily ingestion exposure. The ingestion doses from various metals are greater than inhalation doses, however, the inhalation risks may be greater for certain metals than ingestion. Even when using acceptable drinking water quality that meets regulations for metals, the indoor air quality is still degraded and can pose adverse health effects. In conclusion, the dissertation work presents a framework to estimate risks developed from multi-media and single or multi-metals exposure. The addition from inhalation of aerosolized metals in drinking water should be considered in an overall risk assessment, especially for the susceptible population of young children. Consumers should be aware that they may be degrading their indoor air quality by using ultrasonic humidifiers even when filling with acceptable water quality for drinking.

Asthma, a chronic respiratory disease affecting millions of people worldwide, can vary in severity depending on individual triggers such as Carbon Dioxide, Particulate Matter, dust mites, tobacco smoke, and indoor household activities such as cooking, cleaning, use of heating, and window opening, which can have a negative impact on indoor air quality (IAQ) and exacerbate asthma symptoms. Investigating the relationship between IAQ and asthma severity, a case study was conducted on five asthmatic participants from Bradford, UK. IAQ was measured using IoT indoor air quality monitoring devices. Indoor activities were recorded using a daily household activities questionnaire, and asthma severity was assessed using the Asthma Control Questionnaire (ACQ). Machine learning prediction models were used to analyse various IAQ parameters, such as particulate matter, carbon dioxide, and humidity levels, to identify the most significant predictors of asthma severity with IAQ. The study aimed to develop targeted interventions to improve IAQ and reduce the burden of asthma. Results showed that higher asthma severity scores were associated with increased indoor activity and higher levels of indoor air pollution. Some interventions were implemented to improve ventilation hours, significantly improving IAQ and reducing asthma symptoms, particularly those with more severe asthma. The findings indicate that interventions targeting IAQ, and indoor activities can effectively reduce asthma severity, with up to a 60% reduction in symptoms for asthma patients.

The primary objective of ventilation in a building is to ensure that the Indoor Air Quality (IAQ), together with the heating system, keep the thermal climate at an acceptable level. Meaning the deployment of ventilation air at the appropriate temperature rate supplied to meet the thermal climate into the parts of the building where residents reside. In Sweden, the two most commonly used ventilation strategies are stack ventilation and forced extract ventilation. Both methods utilize exhaust openings in kitchens and sanitary areas, while fresh air is drawn from either permeable external walls or through inlets located near windows and as distant as possible from the exhaust openings (Manz & Huber, 2000). Stack-effect ventilation, also known as buoyancy ventilation, utilizes convective forces. Thus, vertical interior openings such as stairways or atriums play an essential role in the distribution of air and its suitability. Utilizing additional building elements such as a chimney enhances the stack-effect ventilation by elevating the height of the “vertical core” of warm air within the structure. The disparity in density (the difference in temperature between hot and cold) increases as a result of the amplification of pressure disparities (Liu et al., 2010). Hence, larger differences in pressure between the inside and outside will result in an increased driving force for the stack effect by enhancing the convective currents. The principle operates by drawing cooler air from the exterior,generally from the bottom or sides of the building, into the building. The air is then gradually heated and ascends through the vertical core due to convective forces, before being ultimately discharged through the chimney (Savin & Jardinier, 2009). The architectural proposal seeks to adhere to sustainable building development by employing deliberate steps that incorporate a combination of principles and strategies based on the theory of convection. In order to acquire knowledge and validation, an extensive investigation of case studies was carried out, with the works of Philippe Rahm serving as the fundamental basis for further development. Furthermore, a laboratory environment was established to conduct physical tests as well as virtual simulations (CFD) in order to gain deeper understanding and accuracy regarding the relationship between convective forces and geometry. The thesis set out to place a bet based on the notion of consciousness, in terms of implementation of chosen principles, using materials with low embodied carbon, and employing a strategic geometric relationship. This approach enabled the design of an architectural proposal that is both responsive and educative, while also addressing the existing knowledge gap between different professions.

<p dir="ltr">People spend approximately 90% of their time indoors, where they are exposed to a wide variety of particle- and gas-phase air pollutants. The COVID-19 pandemic has intensified the chemical disinfection of high-touch surfaces in occupational workplaces and residential buildings. The use of chemical disinfectants may introduce more pollutants into the indoor environment. These intensive disinfection activities may lead to high human exposure to the released VOC mixtures and potentially adverse effects on the health of disinfection workers and occupants. Thus, it is critical to characterize the VOC mixtures and estimate human exposure during the building disinfection events with various disinfectant products and different disinfection cases and exposure scenarios. This dissertation aims to (1.) evaluate and characterize the VOC emissions during the building disinfections; (2.) assess the low-cost sensor performance to measure VOCs via the PTR-TOF-MS during building disinfections; (3.) compare the VOC measurements and human exposure between breathing zone and bulk air experiment setups; (4.) evaluate the impact of indoor emissions on human exposure during different usage cases of building disinfection.</p><p dir="ltr">To achieve these objectives, this thesis presents three studies based on a field experiment campaign conducted at the Purdue Zero Energy Design Guidance for Engineer (zEDGE) Tiny House in the fall of 2020. First, this thesis presents a study to evaluate the real-time performance of PID in sensing indoor VOC mixtures during building disinfection events through co-location measurements with a PTR-TOF-MS during spray-based disinfectants. The measurements demonstrated that the PID was successful in identifying VOC emission events during the application of the disinfectants. Thus, PIDs may be suitable for integration with building automation systems for ventilation control. The PID response was less than the PTR-TOF-MS response, suggesting that the PID could more efficiently detect many components of the emitted VOC mixtures. Detailed correlation analysis between the PID and PTR-TOF-MS responses provides a basis for improving the reliability of PIDs in estimating VOC concentrations through the application of product-specific correction factors.</p><p dir="ltr">Secondly, this thesis conducts an experimental case study to demonstrate the application of PTR-TOF-MS for mobile breathing zone (BZ) monitoring of VOCs in workplace environments during disinfection activities. Worker inhalation exposure to VOCs was evaluated by attaching the PTR-TOF-MS sampling line to the researcher’s BZ while the disinfection activity was carried out throughout the building. The results show significant spatiotemporal variations in VOC concentrations can occur in the worker’s BZ during multi-surface disinfection events. The application of high-resolution monitoring techniques, such as PTR-TOF-MS, is needed to advance the characterization of worker exposures and develop appropriate mitigation strategies for volatile disinfectant chemicals.</p><p><br></p><p dir="ltr">Lastly, this thesis provides a comprehensive evaluation study on human exposure to VOCs during PAA-based building disinfection events via real-time measurement and disinfection event modeling. The results revealed that PAA-based surface disinfection can lead to an excessive increase in PAA concentrations. BZ experiments demonstrated a spatiotemporal variation in PAA concentrations. The missing mass inhaled measured by the PAA monitor indicated that the human inhalation exposure identified by BZ experiments may be much higher than in bulk air (BA) experiments; thus, a mobile measurement in their breathing zones can better understand the occupants’ exposure to PAA during a building disinfection event. The disinfection event modeling indicated that PAA-based building disinfection may lead to excessive human exposure when using high dilution ratios and/or turning off mechanical ventilation. Such exposure could potentially leave a severe or even irreversible effect on occupant health. These findings suggested that a disinfection protection plan/protocol is necessary for workers, ensuring a required dilution for a disinfectant solution and enough ventilation rate for a safe PAA disinfection event. For the general public who may have difficulties developing professional disinfection procedures, pre-diluted disinfection products with a warning of turning on ventilation could be a more suitable alternative for PAA-based disinfection.</p>

Prior research has shown that indoor air quality (IAQ) impacts cognitive performance. At Cal Poly, many older buildings are unable to maintain appropriate IAQ because of their outdated ventilation systems and the increasing number of students in the rooms. This work analyzes the IAQ of different buildings at Cal Poly, with a focus on Building 20. Carbon dioxide, temperature, and relative humidity inside classrooms are collected using an integrated circuit sensor and a microcontroller. A total of 38 hours of data was collected, with 22 of those hours in Building 20 specifically. We find that unlike temperature and relative humidity, CO2 levels routinely exceed 1,000 ppm—a concentration that hinders cognitive function. A questionnaire distributed to Cal Poly students suggests that while students can recognize poor IAQ in classrooms, they erroneously attribute these poor conditions to temperature and humidity instead of CO2. This data is then used to propose a system which can collect long-term data based on optimal placement, storage, and power requirements.

Forty-three (43) schools in the City of Richmond were used for this study. The rooms in these schools that were selected for testing were those rooms in which complaints about air quality were made by school staff. Tests were done to find out the counts of the different mold species present in these schools. Air-O-Cell (AOC) samples were taken in all schools, swab samples were taken in a few and in the rest biotapes were used. Samples that were taken were analyzed and interpreted at AmeriSci Laboratories, an accredited industrial hygiene laboratory. Documentation was done for the sampling methods. Statistical analysis was run on the data received. Tables of results were made, discussions done and conclusions drawn from the laboratory results.The null hypothesis for this study is that "Total inside mold counts are not elevated above the total outside mold counts in Richmond Public Schools" and the alternative hypothesis is that "Total inside mold counts are elevated above the total outside mold counts in Richmond Public Schools". Biodiversity of molds in the indoor environment should be equal to biodiversity of molds in the outdoor environment for each of the classrooms sampled. Also, Total indoor mold counts exceeding 1000 counts/m3 means that particular school could be faced with a mold problem. In conclusion, it was found out that 58% of the schools sampled could be faced with mold problems, thereby rejecting the null hypothesis, and 42% had no mold problems at all, supporting the null hypothesis. Cladosporium was the most dominant mold genus in the schools and the school with the highest total count of molds in the rooms sampled was Maggie Walker School. Recommendations were then made to reduce the abundance of molds in Richmond Public Schools.