Numerical modeling of particle generation from ozone reactions with human-worn clothing in an environmental chamber

Ozone-terpene reactions are important sources of indoor Ultra Fine Particles (UFPs), a potential health hazard for humans. Humans themselves constitute possible sites for ozone-initiated particle generations through reactions with squalene (a terpene) present in their skin, hair, and clothing. This investigation developed a numerical model to compute particle generations from ozone reactions with human-worn clothing from their measurements in an environmental chamber. The model was capable of predicting size-resolved particle number concentrations and provided insights into the particle generation mechanism. The model captured the overall trend of particle generation, growth, and removal with good accuracy. The model predictions compared very well with the experiments since the "nucleation rate" was directly estimated from the measurements. Hence, it was found necessary to integrate a suitable nucleation model that does not require aid from experimental data to compute nucleation, which will be explored in the future.