Semester

Summer

Date of Graduation

2020

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Industrial and Managements Systems Engineering

Committee Chair

Warren Myers

Committee Member

Gary Winn

Committee Member

Kenneth Currie

Committee Member

Ziqing Zhuang

Committee Member

Anna Allen

Abstract

Many cities around the world experience severe air pollution. According to the World Health Organization (WHO), 7 million people die annually from exposure to small airborne Particulate Matter (PM) that is found in atmospheric pollution. Particulate matter in atmospheric pollution is one of six classifications of common air pollutants and is typically referred to as PM1 and PM2.5. Particulates designated as PM1 and PM2.5 refer to particles having aerodynamic diameters of 1 or 2.5 micrometer (µm), respectively. These size ranges of particles are the most commonly found in air pollution. It is hard to differentiate these particles while in the air, and this poses a threat to human health. Researchers have developed various types of aerosol sampling techniques to help measure and differentiate these different sized particles.

One potential means to help minimize personal exposure to particulate air pollution is the use of nasal filters. A few studies have been conducted on nasal filters to determine their effectiveness in reducing pollen allergy reactions. However, no studies have been found that have evaluated the comfort of wearing nasal filters or their filtration efficiency against these particle sizes found in air pollution.

The main purpose of this research is to measure the efficiency of five new models of nasal filters against two aerosol challenges and to evaluate user comfort while performing various tasks (turning the head side to side, moving the head up and down, normal breathing, deep breathing, bending over, and walking) during exposure to different types and sizes of particulate. The efficiency of these nasal filters has been evaluated against environmental tobacco smoke (ETS) and PM1 size particulate at different flow rates and concentrations.

The mean efficiency values found in ETS and NaCl studies indicated that nasal filters may offer limited protection against ETS and PM1particles. The mean efficiency values under cyclic flow were approximately twice those found under constant flow in ETS and NaCl studies. In the ETS study, the mean efficiency values ranged between 20-30% during constant flow, while the values ranged between 45-65% during cyclic flow under different flow rates. The NaCl study showed relatively lower efficiency values than the ETS study; the efficiency values ranged between 2-29% during constant flow and 33-53% during cyclic flow. Also, the results showed that under a constant flow condition for both ETS and NaCl studies, with increased flow rates, the mean efficiency value increased significantly (P

User perception and acceptability were assessed on six subjects performing different tasks conducted inside and outside of the Respiratory Laboratory on the West Virginia University campus. After completing all tasks, participants were asked to complete a survey about several categories associated with comfort of the nasal filters. In the evaluation study, Eko Mask filter was preferred by participants over the remaining four nasal filters. Eko Mask had the highest mean general comfort score, the lowest inspiratory/expiratory effort score, the lowest mean overall breathing discomfort score, and the lowest mean exertion score. Participants preferred to wear Eko Mask filter for more than six hours per day (6.12 hr). The difference between the mean score for all categories was relatively low and not significant among all models of nasal filters.

Results of the research will be useful to nasal filter manufacturers, researchers, and users. Overall, the findings in this study suggest that to avoid mouth breathing, nasal filters may only be appropriate during light-effort working conditions and with very low exposures. Across the studies, we conclude that further initiative should be taken by manufacturers to improve the filtration efficiency of nasal filters using new or strengthened designs which better consider user comfort, such as improve the filter membrane to increase filtration efficiency and withstand high flow rates while taking into account the user's comfort. The approval of the Institutional Review Board (IRB) at West Virginia University was obtained and the protocol number is 1906614987.

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