Treatment of household product emissions in indoor air: Real scale assessment of the removal processes

Domestic activities involving household products are transient but intense indoor sources of VOCs. Once emitted, pollutants can be processed by indoor air treatment devices. To provide operational conclusions on VOC emissions and their removal by treatment systems, this study explores the issue at real scale: (i) operation of a 40 m(3) experimental room, (ii) representative housecleaning action, and (iii) implementation of selected and commercially available treatment devices. The objective is to challenge the current standards by exploring the behavior of representative air treatment systems and providing a comprehensive characterization of their performances and impacts. First, VOC emissions of selected housecleaning product are characterized as a function of temperature and RH (relative humidity) in the experimental room IRINA. Limonene is identified as a tracer of household product emissions, its removal is investigated. This approach allows discriminating the device performances and identifying the contributions of sorption, photolysis, ozonolysis and photocatalysis in the removal processes. Depending on the media, sorptive and photocatalytic removal are highly contrasted. Third, gas phase side-products generated by each air treatment device are addressed at start up and after 8 h of operation. Remarkably, secondary organic aerosols are identified as side-products of limonene photocatalytic processing. Finally, respective contributions of treated limonene, gas phase and particulate side-products are evaluated through the carbon mass balance of the treatment processes. While the current standard evaluations report equivalent performances for both devices, their real scale evaluation evidence contrasted behaviors. This study shows the effectiveness of providing a comprehensive and real scale characterization of the performances of air treatment devices. It evidences the prospect of moving current experimental approaches related to indoor air investigations to realistic scale and conditions.