Smoke From Outdoor Wood-Fired Boilers Can Be A Health Hazard

Wisconsin is a leader in the number of outdoor wood-fired boilers

Published on: Nov 14, 2013

As the heating season moves into high gear, wood smoke from outdoor wood-fired boilers and other wood heaters will lead to health and nuisance complaints across the state.

The Wisconsin Department of Health Services reports that homeowners who are chronically exposed to smoke often complain of adverse health effects such as asthma, respiratory irritation, sinus issues or headaches. People with lung or heart conditions, children and the elderly are even more at risk from smoke exposure.

Wisconsin is a leader in the number of operating OWBs, and in the absence of regulation this trend is expected to continue. Several features make OWBs a popular alternative heating source: the fire hazard is outside of the building being heated; wood storage and handling takes place outside; and wood is a renewable fuel source that may be less expensive than gas, oil or electricity.

Smoke From Outdoor Wood-Fired Boilers Can Be A Health Hazard
Smoke From Outdoor Wood-Fired Boilers Can Be A Health Hazard

However, there are significant disadvantages to using an OWB for home heating.

"When OWBs are improperly located or operated, or a large number are located in a small area, conflicts with neighbors can occur due to excessive wood smoke and related health effects", says David S. Liebl of UW-Extension's Solid and Hazardous Waste Education Center.

Strong smoke odors combined with a visible plume indicate the presence of fine particulates and chemicals such as carbon monoxide and formaldehyde found in wood smoke. When smoke envelops a neighboring house or property, air quality degrades to conditions similar to what would trigger a DNR air quality advisory for fine particles, according to Liebl. A study of wood smoke in Grand Rapids, Wisconsin found high levels of fine particle pollution from wood smoke in neighborhoods where OWBs we being used.

What causes excessive OWB smoke?

"Installing a stove with a stack that is too short, or at a distance too close to a neighboring building is probably the foremost reason for exposure to OWB smoke," says Scott Sanford, rural energy program specialist with UW-Extension. "Poor design, faulty operation or inappropriate fueling practices also can lead to excessive smoke." For example, operators should only add wood when there is a demand for heat, and only add enough fuel for heating the next 8 to 12 hours (or less) to help reduce smoke emissions.

Poor location, or weather conditions that prevent smoke from dispersing, can also lead to excessive wood smoke. "Neighbors downwind of an OWB may find themselves in the path of frequent smoke plumes from an OWB," Liebl says. "As a public health concern, a visible plume, odors and health or nuisance complaints are sufficient to establish an individual's exposure to OWB emissions."