I-Corps: An Air Purification System for Reducing Indoor Volatile Organic Compounds

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The broader impact/commercial potential of this I-Corps project is that the project can potentially reduce hospital bills on indoor air quality related illness, reduce carbon emissions, and improve the indoor work environment. People spend most of their time indoors, making it critical that we address indoor air quality. In a broader view, this air depolluting system improves the indoor environment in three aspects: reducing volatile organic compounds (VOCs), improving the illumination of buildings by natural light (daylighting), and lowering carbon emissions. Reducing indoor VOCs benefits occupants’ health and well-being, especially for vulnerable groups such as asthma patients. A study conducted at Lawrence Berkeley Laboratory estimated that improved indoor air quality can save $6-14 billion from reduced respiratory disease, $1-4 billion from reduced allergies and asthma, $10-30 billion from reduced sick building syndrome related illness, and $20-160 billion from direct, non-health related worker performance loss. This system can also lead to noticeable productivity gains by improving daylighting quality. A study found that students under better daylighting showed improvement in test scores, for example, they were 20% faster in math and 26% faster in reading. Improving daylighting also reduces energy consumption in artificial lighting and thus lowers carbon emissions. Successful application of this system in commercial buildings is expected to contribute to national energy savings in the building sector up to $30 billion and 280 tons of carbon dioxide reduction. In short, this system is expected to improve the health of building occupants, increase productivity, and reduce carbon emissions.This I-Corps project develops a novel air depolluting system coated with a thin layer of titanium dioxide nanoparticles, one of the most effective photo-induced catalysts to remove air pollutants. The system is designed to be installed in interior spaces behind windows in contact with indoor air while receiving UV-A rays coming through windows. The efficiency of titania breaking down VOCs primarily depends on three parameters: the dose of effective UV rays, contact surface area, and airflow. The efficiency monotonically increases as any one of the three parameters increases. The primary challenge is that improving one parameter can negatively affects the other two. To maximize overall VOC reduction, a multi-objective optimization algorithm is used to balances UV ray incident angles, contact surface area, and airflow. This air depolluting system is a completely passive system which means that it does not contain any mechanical/electrical device and does not require power to operate, which lowers initial costs and minimizes maintenance.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.