Fine Particulate Matter Concentrations in Outdoor Air near Outdoor Wood-Fired Boilers


picture showing a typical outdoor wood boiler

Outdoor wood boilers (OWBs) can be substantial sources of wood smoke and fine particulates (PM2.5). By one estimate, PM2.5 emissions from one OWB are equivalent to 22 EPA-certified woodstoves, 205 oil furnaces, or as many as 8,000 gas furnaces.


Outdoor PM2.5 levels at residences near OWBs were compared to levels at residences distant from OWBs. An analysis of whether extreme PM2.5 levels at residences near OWBs coincided with wind conditions favoring local accumulation of OWB smoke (calm winds) or transport towards the monitors was also conducted.


Geomean PM2.5 levels were statistically significantly elevated at five of six nearfield monitors, located 150 to 1,270 feet from the nearest OWB, compared with reference monitors in the same area but ≥2,500 feet from an OWB. The odds of observing an extreme PM2.5 level were 1.8- to 4.3-fold higher at these five nearfield monitors (statistically significant). Calm winds were statistically significantly associated with increased odds of an extreme PM2.5 difference (nearfield PM2.5-reference PM2.5) at four of the five sites. "Downwind" was statistically significantly associated with increased odds of an extreme PM2.5 concentration difference at three of the five sites.


Study results indicate that OWBs can significantly increase PM2.5 levels. Given the severity of adverse health effects from even short-duration PM2.5 exposures, along with the demonstrated importance of OWBs to wood smoke and PM2.5 in some residential settings, efforts to reduce exposures to OWB wood smoke and PM2.5 are warranted.

For More Information

If you would like additional information about this study or the health effects of fine particles, please call the Department of Health at 518-402-7800 or 800-458-1158.