Modeling indoor exposures to VOCs and SVOCs as ventilation rates vary

An important role of building ventilation is to limit the indoor concentrations of pollutants emitted from indoor sources. Changes in ventilation rate will impact the concentrations of VOCs and SVOCs in buildings depending on factors such as source location and phase partitioning. We used a fugacity-based mass balance model to simulate the impact of ventilation on indoor concentrations of VOCs and SVOCs. We found that increased ventilation is effective at controlling indoor exposures to VOCs emitted from indoor sources that have low octanol-air partitioning coefficients (log(Koa) < 9). For typical ventilation and filtration systems, increased ventilation is ineffective in controlling indoor concentrations of SVOCs with high octanol-air partitioning coefficients (log(Koa) > 12). This is because SVOCs are attached to particles, for which removal by filtration and deposition usually dominates. Results from this analysis are useful for identifying pollutants of concern while setting standards of minimum ventilation rates in commercial buildings.