Ozonolysis of monoterpenes in mechanical ventilation systems

In this investigation the ozonolysis of of three monoterpenes (α-pinene, Δ3-carene and limonene) was studied was studied in authentic mechanical ventilation systems, that included either a cross flow or a rotary heat exchanger. The effects of varying three experimental parameters were investigated: the level of ozone (25 and 75 ppb), the reaction time (25 and 75 s), and the surface area in the ventilation duct (14.8 and 29.5 m2). The initial concentration of each of the monoterpenes was 20 ppb in every experiment, and 1–16% of the α-pinene, <0.5–13% of the Δ3-carene, and <0.5–16% of the limonene reacted. The effects of humidity (g m−3) and temperature of the outdoor and supply air, and water losses in the ventilation duct, were also evaluated. Experiments were based on a chemometric statistical design. Comparison of the results to theoretically calculated values showed that theoretical calculations underestimated the amounts that reacted in the ventilation systems by factors of 2–13, depending on the monoterpene and experimental settings.