Temperature driven variations in VOC emissions from plastic products and their fate indoors: A chamber experiment and modelling study.

Plastic products are ubiquitous in our homes, but we know very little about emissions from these products and their subsequent impact on indoor air quality. This is the first study to systematically determine temperature-dependent emissions of volatile organic compounds from commonly used plastic consumer products found in the home. The plastic types included high-density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS) and polyester rubber. Plastic samples were exposed to increasing temperatures (between 18 and 28 °C) in controlled environmental chambers, connected to a proton-transfer-reaction time-of-flight mass-spectrometer (PTR-ToF-MS), where real-time emissions were detected. Average emission rates were determined and used to initialise an indoor air chemistry model (INCHEM-Py) at the highest and lowest experimental temperatures, to explore the impact these product emissions have on the indoor air chemistry. The PS tubing plastic proved to be the highest emitting polymer per surface area. Almost all selected VOC emissions were found to have a linear relationship with temperature. Upon observing the impacts of primary VOC emissions from plastics in modelled simulations, the hydroxyl radical concentration decreased by an average of 1.6 and 10 % relative to the baseline (with no plastics included) at 18 °C and 28 °C respectively. On the other hand, formaldehyde concentrations increased by 29 and 31.6 % relative to the baseline conditions at 18 °C and 28 °C respectively. The presence of plastic products indoors, therefore, has the potential to impact the indoor air quality.