Chemical reactions can have a significant effect on indoor concentration levels by decreasing or increasing pollutant levels and producing products that would not normally be present. For this work, a computational fluid dyanamics (CFD) model that has been validated for flow field predictions will be improved to predict the concentrations of Ozone, Squalene and oxidation products. The use of surface reactions were validated with experimental data by Rim et al. (2009) who studied the Ozone/human body reaction on a cylinder in a stainless steel chamber and agreement was achieved to within the experimental error. After validation, a hypothetical reaction was studied in a typical office setup with optional personal ventilation (PV) systems. The results show that, the concentration distribution is not well mixed. For circumstances where indoor sources or chemical reactions are present in the indoor environment, assuming well mixed distributions can lead to significant over or under prediction of inhalation exposure. The results also show that PV can reduce inhalation exposure to reaction products by a factor of four.