Health effects of PM2.5 emissions from woodstoves and fireplaces in living spaces

Abstract

Increased exposure to airborne fine particle pollution (PM2.5) can result in decreased life expectancy (DLE). However, while wood-burning in woodstoves and fireplaces for domestic space heating is a major source of indoor and outdoor PM2.5, the emission factor of PM2.5 into the occupied space was unknown for use periods of 3–4 h, as was the resulting DLE. This paper presents a three-phase analysis of the DLE due to the use of firewood for indoor residential space heating. The first phase was a measurement study of the emission of PM2.5 from wood-burning equipment, namely woodstoves and fireplaces, into the occupied space. The second phase used building thermal and airflow simulation to estimate the increased exposure to PM2.5 due to the use of wood-burning equipment. The third phase used existing correlations to predict the DLE due to domestic wood-burning. Results show that fireplaces emit 58.0 mg of PM2.5 per kg of firewood, standard woodstoves emit 21.6 mg/kg, and woodstoves with a dedicated outside air admission channel emit 1.4 mg/kg. Consequently, using a fireplace to supply a living room's heating load for 4 h/day during the evening could shorten life expectancy by 1–1.6 years, while a woodstove that is used during the same period to supply the heating needs of a single-family townhouse building could reduce overall life expectancy by up to half a year. The woodstove with outdoor air admission drastically restricted the emission of PM2.5 into the occupied space, resulting in negligible impacts on occupant life expectancy.