Trace Contaminant Removal from Air via Photocatalytic Oxidation

Photocatalytic oxidation (PCO) has been evaluated for potential use in trace contaminant removal and disinfection of air from commercial aircraft cabins and spacecraft. For space applications, PCO has the advantage that contaminants are destroyed, rather than stored, or discharged to space, and that contaminants such as carbon monoxide, can be removed using the same system as any other oxidizable contaminant. In this paper, we report experimental studies showing the photocatalytic oxidation of trace contaminants at concentrations comparable to those expected in human-occupied space vessels or aircraft cabins. Competitive rate studies between various pollutants and acetaldehyde have been completed, and oxidative byproducts have been identified and quantified for several organic contaminants and carbon monoxide. Ozone removal has also been demonstrated under photocatalytic conditions.

Removal of trace contaminants by PCO is expected to improve alertness, and decrease the incidence or intensity of symptoms such as eye, skin or nasal irritation. Our results are in agreement with other studies using our photocatalyst system demonstrating such improvements.