INFLUENCE OF ENVIRONMENTAL PARAMETERS ON PCO REMOVAL EFFICIENCY OF TWO OPERATING ROOM POLLUANTS
Résumé
The hospital environment is a complex one compared to others like residential and commercial buildings. The complexity lies in the fact that there are several zones where specific activities are performed and consequently, occupants (hospitals workers, patients, etc) are exposed to a wide variety of chemical pollutants (Leung and Chan, 2006) (Gangneux et al, 2017). Additionally, these different zones have different indoor air quality (IAQ) requirements. Operating rooms (ORs) are one of the most demanding zones in terms of IAQ and thus require systems that minimize the concentrations of pollutants (bioaerosols, chemical pollutants and particulate matter). Air treatment devices that use photocatalytic oxidation (PCO) could potentially be used in the OR to improve IAQ. In this work, the fate of two OR pollutants acrylonitrile (chemical found in surgical smoke) and isoflurane (anesthetic gas) was investigated. For the first time, experiments were conducted in a laboratory closed loop multi-pass reactor to investigate the effect of environmental parameters on the PCO removal efficiency of isoflurane and acrylonitrile. The study looks at the influence of three environmental parameters; relative humidity, presence of co-pollutants and presence of particles on their degradation under relevant conditions to actual applications. The closed loop reactor used in this work allows the study of air pollutants at low concentrations and has also been recently modeled (Dumont and Héquet, 2017) (Héquet et al, 2017). This reactor permits a better representation of PCO systems functioning in dynamic mode and is realistic regarding air treatment systems working as standalone devices or implanted in HVAC systems. A mathematical model was utilized to enable the calculation of one indicator (single-pass removal efficiency) for acrylonitrile and two indicators (induction period and single-pass removal efficiency) for isoflurane. The degradation efficiency was then accessed by studying the influence of environmental parameters on these indicators. Figure 1 presents an example of the degradation profile of acrylonitrile and the determination of the single pass removal efficiency (α) whilst Figure 2 shows an example of the degradation profile of isoflurane and the determination of the single pass removal efficiency (α) and the induction period ( i).