Performance evaluation of a gaseous pollution control device suitable for in situ heating, ventilation and air conditioning applications

Air pollution is a ubiquitous problem plaguing global citizens with decreased quality of life. Pollutants are created both indoors and out and contribute to poor indoor and ambient air quality. Indoor air purification technologies have been created and are successful in removing particulate matter, though there are severe limitations and environmental repercussions with existing technologies used to eliminate gaseous pollutants. To address this need, research and development led to the creation of a gaseous pollution control device which uses a patented photocatalyst capable of simultaneously destroying both volatile organic compounds and nitrogen oxides over extended time durations. A laboratory-scale prototype was built and a rigorously tested to evaluate the removal of nitric oxide and select volatile organic compounds (formaldehyde, ethanol and limonene). The test campaign used various velocities, surface conditions, length scales, light power outputs and pollutant compositions to generate a statistically relevant data set for evaluating performance. Performance evaluation of the two prototype units produced reduction efficiency between 550–60% for formaldehyde, 60–85% for nitric oxide, 80–99% for limonene, and 100% for ethanol, over the air velocity range of 0.5 to 2.0 m s−1. Removal efficiency of the unit appears to be most dependent on the molecular structure (i.e., bond strength) of the pollutant and the pollutant residence time within the unit (i.e., velocity or having multiple units in series). Additionally, there are opportunities for optimizing performance of the units through controlling power output of the illumination source or periodically performing a simple water rinse.