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Vehicle Exhaust Effects

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Resulting Legislation
An Act Concerning Clean Air Strategies

This study investigates how homes are affected by neighboring outdoor wood furnaces, as well as the health implications for the families living inside homes impacted by wood smoke.

In this report, Environment and Human Health, Inc. (EHHI) explains its study, which measured potential wood smoke inhalation by people living in homes in the vicinity of outdoor wood furnaces (OWFs), also known as outdoor wood boilers (OWBs). EHHI’s study monitored levels of PM2.5 and PM0.5 particles in each house for 72 hours.

The U.S. Environmental Protection Agency (EPA) has shown that PM2.5 and PM0.5 are the most common size particles in wood smoke. PM2.5 and smaller cause the greatest health impacts because they are small enough to go deep inside the lungs, where they can not only damage the lungs, but also pass through into the blood stream, delivering their toxins throughout the body. EHHI’s study was performed over three days, for 72 hours per house, in each house that was monitored. This is the only study of its kind to date.

Key background information about wood smoke:

  • Large amounts of wood smoke, like the plumes from OWFs, cannot be kept out of neighboring houses, even those with tight windows and doors.
  • Wood smoke has many of the same components as cigarette smoke and, therefore, these exposures pose a real health risk for families living in the vicinity of OWFs.
  • Wood smoke is a complex mixture of chemicals and particulates. It contains carbon monoxide and other organic gases, particulate matter, chemicals and some inorganic gases. Some of these compounds are toxic (aldehydes and phenols) and some are known carcinogens (benzopyrene and cresols).
  • Wood smoke contains carbon monoxide (CO) gas, which at low levels can lead to serious health problems for individuals with compromised heart and circulatory conditions. OutdoorWood Furnaces Large amounts of wood smoke, like the plumes from OWFs, cannot be kept out of neighboring houses, even those with tight windows and doors.
  • Particulate matter in wood smoke that is less than 10 microns in diameter finds its way into the alveoli in the lungs. Once in the alveoli, the particulate matter can cause structural and chemical changes, which interfere with oxygen uptake. As well, the toxic compounds and carcinogens enter into the bloodstream by way of the alveoli of the lungs.
  • Episodes of short-term exposures to extreme levels of fine particulates from wood smoke and other sources, for periods as short as two hours, produce significant adverse health effects.
  • Wood smoke interferes with normal lung development in infants and children. The components of smoke increase children’s risk of lower respiratory infections, such as bronchitis and pneumonia. Wood smoke exposure can depress the immune system and damage the layer of cells in the lungs that protects and cleanses the airways.
  • Wood smoke causes coughs, headaches, and eye and throat irritation in otherwise healthy people. For vulnerable populations, such as people with asthma, chronic respiratory disease and those with cardiovascular disease, wood smoke is particularly harmful—even short exposures can prove dangerous.
  • Children and the elderly have the highest sensitivity to wood smoke. However, no age group is without risk for respiratory problems, including asthma and chronic obstructive pulmonary disease (COPD), that result from breathing wood smoke. The effects are cumulative.
  • The air impact of health exposure to wood smoke is increased two-fold during periods with stagnant air. Under such conditions, the inhaled dose levels of particulates within houses approach the hazardous level found in regulated work sites by OSHA. EHHI found smoke entering houses, every day, at even higher levels. The Dangers to Health from A study by the University of Washington in Seattle showed that 50 to 70 percent of the outdoor levels of wood smoke were entering homes that were not burning wood. The EPA performed a similar study in Boise, Idaho, with similar results.
  • The particulate matter and gases in wood smoke are so small that windows and doors cannot keep them out—even the newer energy-efficient, weather-tight homes cannot keep out wood smoke. This is consistent with reports from people in the EHHI study who say their children awaken in the middle of the night having difficulty breathing.
  • In 2009, the state of Massachusetts commissioned a study on the environmental impacts of burning wood for electricity. That study, conducted by the Manomet Center for Conservation Sciences, has now been released. The Manomet study shows that, per unit, wood releases more climate-damaging gases than coal.



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