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Wood Burn Program

How to Reduce Wood Smoke Emissions

The public can take the following simple steps to reduce the impacts of wood smoke, particularly during inversions:

The Wood-Burn Program is designed to prevent particle pollution by restricting or banning wood burning during inversion periods. Emissions from wood-burning stoves and fireplaces contribute to the particulate pollution that builds up during temperature inversions.

Inversions form when a dense layer of cold air is trapped under a layer of warm air. The warm air acts like a lid, trapping pollutants in the cold air near the valley floor. The mountains act like a bowl, keeping the cold air—and the pollutants in it— in the valleys.

Wood burn restrictions are a proactive measure that can reduce the levels of particulates emitted both immediately before and during inversions.

Impacts from Wood Smoke

Because wood doesn’t burn completely, wood smoke contains a wide range of harmful substances. Pollutants in wood smoke include particulates, volatile organic compounds (VOCs), and hazardous air pollutants (HAPs), some of which are toxic or considered carcinogenic. These pollutants include:

  • Benzene
  • Formaldehyde
  • Carbon monoxide
  • Nitrogen dioxide
  • Particulates
  • Polycyclic aromatic hydrocarbons (PAH)
  • Sulfur dioxide

The poor air circulation that typifies inversions keeps wood smoke close to the ground where it can enter homes and businesses. The fine particle pollutants from wood burning are so small that even well-insulated houses can’t keep them out. Scientific studies have shown that particle pollution levels inside homes reach up to 70 percent of the pollution levels outdoors. Studies have also shown that people using wood-burning stoves and fireplaces to heat their homes are regularly exposed to high levels of fine particulate matter in their indoor air, particularly if there is little fresh air circulating inside the house.

Health Effects

Because the fine particles in wood smoke are too small to be filtered out by the upper respiratory system, they lodge deeply into the lungs, causing irritation and decreasing lung functioning. The toxic and carcinogenic chemicals that are released in wood smoke can bind with these particles, compounding the health impacts. Short-term exposures to particles can aggravate lung disease, cause asthma attacks and acute bronchitis, and increase susceptibility to respiratory infections.

People with heart or lung disease, such as congestive heart failure, angina, chronic obstructive pulmonary disease, emphysema, or asthma may experience health effects earlier and at lower smoke levels than healthy people. Older adults are more likely to be affected by smoke, possibly because they are more likely to have chronic heart or lung diseases than younger people. Children also are more susceptible to smoke because their respiratory systems are still developing, they breathe more air per pound of body weight than adults, and they’re more likely to be active outdoors.

Numerous studies link particulate levels to increased hospital admissions, emergency room visits, and even early death. Research indicates that obesity or diabetes may increase the risk. Some studies also suggest that long-term PM2.5 exposure may be linked to cancer and to harmful developmental and reproductive effects such as infant mortality and low birth weight.

“Wood smoke can cause serious health effects, particularly for children.”

The World Health Organization (WHO) released the following publication on the impacts of wood burning and your health. WHO paper on residential heating: Residential heating with wood and coal is an important source of ambient (outdoor) air pollution; it can also cause substantial indoor air pollution through either direct exposure or infiltration from outside. Evidence links emissions from wood and coal heating to serious health effects such as illness and death from respiratory and cardiovascular diseases. Burning wood and coal also emits carcinogenic compounds: Residential heating with wood and coal: health impacts and policy options in Europe and North America

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