SOA in newly decorated residential buildings

Secondary organic aerosols (SOA) are products of the reaction of reactive organic gases (ROGs) and ozone. Most SOA are in the nanometer or submicron range, and thus SOA may be harmful to human health. Concentrations of ROGs may be high in newly decorated rooms, which may result in high SOA concentrations, especially during seasons with high ozone concentration. The objective of this study was to investigate the concentrations of SOA and the extent to which SOA contribute to indoor PM2.5 concentrations in newly decorated residential buildings. We measured concentrations of ROGs in 24 rooms of eight newly decorated (within the preceding three months) residential buildings in Beijing, China. Using previously measured indoor ozone decay rates, air change rates, and corresponding monitored ozone concentrations, we estimated the indoor ozone concentrations for the newly decorated rooms. Subsequently SOA concentrations were calculated using an aerosol mass fraction (AMF) model. We further estimated the fractions of SOA concentrations in indoor PM2.5. The SOA concentrations in 18 of the rooms ranged from 0.88 to 18.18 μg/m3, contributing to between 3.77% and 78.57% of indoor PM2.5 concentrations. The other six rooms had much lower SOA concentrations, less than 0.1 μg/m3, contributing to less than 0.39% of indoor PM2.5 concentrations. The results indicate that the concentrations and contribution of SOA in most newly decorated residential rooms are much higher than those in rooms with long-term occupancy, while some newly decorated rooms can still have low SOA concentrations.