Residential wood stove use and indoor exposure to PM2.5 and its components in Northern New England

Background Residential wood stove use has become more prevalent in high-income countries, but only limited data exist on indoor exposure to PM2.5 and its components. Methods From 2014 to 2016, we collected 7-day indoor air samples in 137 homes of pregnant women in Northern New England, using a micro-environmental monitor. We examined associations of wood stove use with PM2.5 mass and its components [black carbon (BC), organic and elemental carbon and their fractions, and trace elements], adjusted for sampling season, community wood stove use, and indoor activities. We examined impact of stove age, EPA-certification, and wood moisture on indoor pollutants. Results Median (IQR) household PM2.5 was 6.65 (5.02) mu g/m(3) and BC was 0.23 (0.20) mu g/m(3). Thirty percent of homes used a wood stove during monitoring. In homes with versus without a stove, PM2.5 was 20.6% higher [although 95% confidence intervals (-10.6, 62.6) included the null] and BC was 61.5% higher (95% CI: 11.6, 133.6). Elemental carbon (total and fractions 3 and 4), potassium, calcium, and chloride were also higher in homes with a stove. Older stoves, non-EPA-certified stoves, and wet or mixed (versus dry) wood were associated with higher pollutant concentrations, especially BC. Conclusions Homes with wood stoves, particularly those that were older and non-EPA-certified or burning wet wood had higher concentrations of indoor air combustion-related pollutants.