Indoor/outdoor relationships for ambient PM2.5 and associated pollutants: Epidemiological implications in Lindon, Utah

Outdoor and indoor fine particulate species were measured at the Lindon Ele mentary School in Lindon, Utah, to determine which components of ambient fi ne particles have strong indoor and outdoor concentration correlations. PM2 .5 mass concentrations were measured using tapered element oscillating micr obalance (TEOM)(7) monitors and by gravimetric analysis of Teflon filter sa mples. Gas-phase HNO3, sulfur dioxide, particulate nitrate, strong acid, an d particulate sulfate were measured using annular denuder samplers. Soot wa s measured using quartz filters in filter packs. Total particulate number w as measured with a condensation nucleus counter (CNC). Total particulate nu mber and fine particulate sulfate and soot were correlated for ambient and indoor measurements. Indoor PM2.5 mass showed a low correlation with outdoo r PM2.5 mass because of the influence of coarse-material from student activ ities on indoor PM2.5. Fine particle acidity and the potentiation of biolog ical oxidative mechanisms by iron were not correlated indoors and outdoors.