Mass balance modeling of building recirculation rates and filtration efficiencies effects on secondary organic aerosols derived from ozone-initiated chemistry

Recirculation of conditioned air is a common practice in regions with hot and humid climate. This is due to the need to reduce sensible and latent cooling loads in buildings. However, recirculating used indoor air may influence indoor air chemical reactions and products derived from the chemistry. Example of such products is secondary organic aerosols (SOA) derived from ozone initiated indoor chemistry. This present study was conducted using mass balance model to examine the impacts of four recirculation rates on ozone (of outdoor origin) and SOA derived from the ozone initiated indoor chemistry. At steady-states, it was observed that the higher the recirculation rate, the lower the ozone and SOA concentration for all modeled scenarios. At steady-state, outdoor to indoor transport of ozone, indoor ozone and SOA concentrations were found to increase with increasing outdoor ozone levels. Increase in ventilation rate was found to increase outdoor to indoor transport of ozone and steady-state indoor ozone concentration. However, higher ventilation rate resulted in lower SOA concentration at steady-state. Increasing ozone filtration efficiency of activated carbon (AC) filter was found to be effective in reducing indoor ozone and SOA concentrations. This study is relevant to building sustainability in terms of health and comfort of building occupants.