Ultraviolet and Titanium Dioxide Based Photocatalysis HVAC System to Eliminate COVID-19 for Occupant�s Safety & Health in Automobiles

Abstract

In a photocatalytic air purifier system, the catalyst that cleans the air is typically titanium dioxide and it is energized by ultraviolet (UV) light. UV is the short-wavelength light just beyond the blue/violet part of the electromagnetic spectrum that our eyes can detect. This shortwave-length light has much more energy than ordinary, visible light�and exactly the right amount of energy to get titanium dioxide excited. Titanium dioxide is a semiconductor that covers the filter surface. Just a thin film of titanium dioxide is required at the filter surface with a substrate. When UV light shines on the titanium dioxide, electrons (negatively charged particles inside atoms) are released at its surface. The electrons interact with water molecules (H2O) in the air, breaking them up into hydroxyl radicals (OH�), which are highly reactive, short-lived, uncharged forms of hydroxide ions (OH−). These small, agile hydroxyl radicals then attack bigger organic (carbon-based like virus) pollutant molecules, breaking apart their chemical bonds and turning them into harmless substances such as carbon dioxide and water. Current investigation uses the above principle to kill living organic germs, bacteria; pathogen,viruses etc. from the cabin air. A HVAC system has been developed by using a filter impregnated by titanium di-oxide (TiO2) with UV lights to improve and maintain cabin air quality. This system can be used for conventional vehicles with internal combustion vehicles; EVs and HEVs; vehicles with start-stop feature; and autonomous vehicles. The same concept designs can also be used for high occupancy transportation modes like taxis, buses, trains and airplanes. The author has designed and constructed a UV based photocatalysis system to kill germs, pathogens and bacteria that typically exists in a conditioned space. Tests were conducted at a certified laboratory with bacteria and virus in the conditioned space. Effectiveness of the destruction rate was determined for the developed system. Detailed summary will be presented in the paper.