Outdoor wood furnaces create significant indoor particulate pollution in neighboring homes.

CONTEXT The use of outdoor wood furnaces (OWFs) is common in many parts of the United States. Little published information exists on the concentrations of outdoor and indoor fine particulates found near OWFs. OBJECTIVE To compare PM2.5 (cts) and PM0.5 (cts) particle concentrations inside four Connecticut homes located 30.5-259 m from OWFs, and inside six Connecticut control homes located more than 2 km from the nearest OWF. MATERIALS AND METHODS PM2.5 (cts) and PM0.5 (cts) measurements were made with a Dylos light-scattering particulate counter. RESULTS Mean PM2.5 (cts) concentrations were 4.21 times as great in the four OWF exposed homes than the six control homes (0.302 × 10(6) counts/m(3) versus 0.0718 counts × 10(6)/m(3) p < 0.001). The mean PM2.5 (cts) concentrations inside the four OWF exposed homes roughly corresponds to a mass PM2.5 of 37 µg/m(3), which is above the US EPA 24-h PM2.5 limit of 35 µg/m(3). Mean PM0.5 (cts) concentrations were 3.44 times as great in the four OWF exposed homes than in the six control homes (0.657 versus 0.191 × 10(6)/m(3) p < 0.001). Mean PM2.5 (cts) and PM0.5 (cts) concentrations were significantly higher in the house 259 m from an OWF as compared with the mean of the six control homes. CONCLUSION Existing regulations, such as the present Connecticut law requiring a 61 meter distance between an OWF and neighboring homes, are not adequate to protect the health of neighboring residents.