Particulate Matter 2.5 Exposure and Self-Reported Use of Wood Stoves and Other Indoor Combustion Sources in Urban Nonsmoking Homes in Norway

Few studies have examined particulate matter (PM) exposure from self-reported use of wood stoves and other indoor combustion sources in urban settings in developed countries. We measured concentrations of indoor PM < 2.5 microns (PM 2.5 ) for one week with the MicroPEM ™ nephelometer in 36 households in the greater Oslo, Norway metropolitan area. We examined indoor PM 2.5 levels in relation to use of wood stoves and other combustion sources during a 7 day monitoring period using mixed effects linear models with adjustment for ambient PM 2.5 levels. Mean hourly indoor PM 2.5 concentrations were higher (p = 0.04) for the 14 homes with wood stove use (15.6 μg/m 3 ) than for the 22 homes without (12.6 μg/m 3 ). Moreover, mean hourly PM 2.5 was higher (p = 0.001) for use of wood stoves made before 1997 (6 homes, 20.2 μg/m 3 ), when wood stove emission limits were instituted in Norway, compared to newer wood stoves (8 homes, 11.9 μg/m 3 ) which had mean hourly values similar to control homes. Increased PM 2.5 levels during diary-reported burning of candles was detected independently of concomitant wood stove use. These results suggest that self-reported use of wood stoves, particularly older stoves, and other combustion sources, such as candles, are associated with indoor PM 2.5 measurements in an urban population from a high income country.