Wood Smoke Exposure



The health effects of wood smoke are related to one’s exposure. Exposure is a function of the size, intensity and proximity of the fire, the duration and frequency of wood burning, and the topography and weather or meteorology. The weather has an effect on the movement and dispersion of wood smoke in the vicinity of the source. When these factors are detrimental to mitigating wood smoke air pollution, the activity, if any, should be subject to legal consequences. One should understand the risks as to wood smoke and what is necessary under the law to ensure the air quality in one’s home, on one’s property and in one’s community.


Intensity and Proximity

The intensity of wood smoke is a factor of the fire size, combustion efficiency and temperature, wood moisture content, airflow, type and amount of wood and proximity to the source.

Duration and Frequency

The amount of wood smoke exposure and the levels of harmful chemicals/toxins in it depends on the heat of combustion, the time it takes for the smoke to rise and spread, and the amount of time and how often one is breathing wood smoke indoors and outdoors.


Geography and topography can be pivotal as to wood smoke health risks on a community-wide level. Individuals that live in valleys where air tends to stagnate face higher risks of exposure to wood smoke from open burning, indoor appliances and outdoor wood boilers in the vicinity.

Topography can present barriers to or limit air movement and contribute to or trap smoke, particulate and malodorous emissions at or in occupied dwelling(s), and  building(s) or space(s) at or beyond the source property line under the prevailing meteorological conditions.

Meteorology (Weather)

Wood smoke consists of gases and tiny particles. The microscopic particulate pollution – or particle matter (PM) e.g., PM 2.5 (2.5 micrometers in size), travels through the atmosphere to spaces (indoors and outdoors) in the vicinity of the source. Since the weather defines the current state of the atmosphere at a given time and place, wood smoke can be more problematic for example in the winter when a temperature inversion traps cold air near the ground and prevents pollutants in the smoke from rising and dispersing. In neighborhoods where there is residential wood burning (RWB), houses can have higher indoor wood smoke pollution levels than houses in neighborhoods where there is no RWB. The wood smoke from another’s burning can enter one’s house despite closed doors and windows; so, the occupants are breathing another’s smoke (2nd Hand Residential Wood Smoke (RWS)). The prevailing meteorological conditions, including but not limited to wind direction, low windspeed, downwind status, high pressure, humidity, temperature, air movement and strong overnight temperature inversions all contribute to the accumulation of or transport of smoke (plumes), particulate and malodorous emissions.

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