Use of a State Space Model to Study the Effect of Outdoor Air Quality on Indoor Air in Fairbanks Alaska

A usual method for studying the effective penetration efficiency of pollutants into buildings consists in performing a linear regression of outdoor and indoor samples. But, because of the dynamic relationship between outdoor and indoor concentrations, this method requires either long-term averages or steady-state conditions. Other methods use dynamic models but these normally require the knowledge of model parameters, such as the ventilation rate. This paper presents a state-space model analysis method that can be used for transient samples and doesn’t require the knowledge of model parameters. It was used to study PM2.5 and CO in Fairbanks, Alaska. The effective penetration efficiency for PM2.5 ranged from 0.16 to 0.69, and was close to unity for CO. The outdoor generated PM2.5 was responsible in average for about 67% of the indoor PM2.5 in residences, and close to 100% in office environments.