Water vapour mobilises building related non-volatile chemicals and mycotoxins and may be used to remove substances of potential health hazard from indoor surfaces

No inhalation toxicity assessment (H314) is currently required of non-volatile substances (European REACH). However, our study shows that non-volatiles can mobilise into humid air. Aerosolisation of potentially hazardous, medium to large molecular-size (300 – 1500 g/mol) substances relevant to indoor air quality were studied in glass test chambers. The test substances, which are classified non-volatile based on their large molecular structure and lack of vapour pressure data, were: 1) toxins of building colonizing moulds, 2) biocidal cationic antimicrobials, and 3) non-ionic tenside and wetting agent polyoxyethylene isotridecanol ether, widely used in building materials and a major constituent of indoor cleaning formulations.
Each test substance (0.9 – 30 mg) was dosed on a glass tray, placed on the chamber floor. Humidity was controlled by a humidifier and a dehumidifier and intermittent ventilation. Humidity-driven mobilisation of the non-volatile substances transferred the substances from the tray into chamber air, where it was detected with TVOC sensors. The water vapour was condensed in the dehumidifier, where the test substances could be detected using capillary electrophoresis analyser.
Humidification and dehumidification and ventilation removed the test substances from the trays at ambient. This protocol could be applied to contaminated indoor spaces during low activity hours to reduce human exposure the adverse substances.