Doctor’s Orders: Wood Burning Hazardous to Your Health
- by Dr. Brian Moench, Utah Physicians for a Healthy Environment
Civilization orchestrates the curbing of one person’s freedoms for the protection of others and the greater good. When two people’s freedoms are mutually exclusive, civilization embraces the concept that the freedom to not be harmed by others takes precedence. Traffic laws, zoning ordinances, and regulations governing air travel are all examples of that priority. In fact, virtually all laws that allow a free society to rise above chaos, anarchy and barbarism are the result of a similar calculation.
We all accept that freedom for one person to smoke on an airplane has been subjugated to freedom for all the other passengers to breathe clean air. In cities throughout North America there is a growing recognition that wood burning in an urban setting should be considered as much of an anachronism as smoking on an airplane.
Two years ago in my home state of Utah, the most conservative state in the nation, our equally conservative governor, Gary Herbert, declared in his opening speech to our legislature that he would pursue a ban on wood burning throughout the winter season in our largest cities--a truly remarkable development. Here’s what led to that proposal.
In most major, northern cities, wood burning can be as much of a source of the worst kind of community air pollution as all vehicle exhaust. Such is the case where I live in Salt Lake City, Utah. Even in Los Angeles, a study showed that in the winter, residential wood combustion there contributed 30 percent of primary organic aerosols (probably the most important mass component of particulate pollution), more than motor vehicle exhaust, which contributed 21 percent. But that is only the beginning of the story.
Wood smoke is uniquely toxic among all contributors to urban air pollution. The free radical chemicals in wood smoke are active forty times as long as those from cigarette smoke, resulting in a greatly prolonged opportunity to damage individual cells. Other studies suggest that the lifetime cancer risk from wood smoke is twelve times greater than that from an equal volume of second hand tobacco smoke.
Particles in wood smoke are extraordinarily small, behaving essentially like gases, which amplifies their human health impact in multiple ways. The small size makes them easy to inhale into the smallest recesses of the lungs and less likely to be exhaled. They are then picked up by the blood and distributed throughout the body, causing inflammation and biologic disruption wherever they go.
The small size even allows these particles to enter individual cells and critical sub cellular structures like the mitochondria and nucleus, where the all important chromosomes lie. These particles can directly interact with and change the functioning of chromosomes, literally within minutes after exposure, which plays a prominent role in many serious diseases.
Attached to these tiny wood smoke particles are at least 200 of the most toxic compounds known--dioxins, furans, formaldehyde, heavy metals, and polycyclic aromatic hydrocarbons (PAHs). One fireplace burning 10 pounds of wood in an hour will release as many PAHs as 6,000 packs of cigarettes. No one in their right mind, even smokers, would think that sitting in front of 6,000 smoldering packs of cigarettes during a cozy winter evening would be a good idea.
Pollution concentrates near its sources. Unlike Las Vegas, what happens in your chimney obviously doesn’t stay in your chimney. For most people residential and restaurant wood smoke is just about the only type of serious pollution emitted right next to your home, from a height where dispersion is minimal, creating local pollution hot spots. And this is the worst possible place for exposure because people generally spend most of their time at home, especially during the winter.
Furthermore, your home provides little protection from a wood-burning neighbor. The small size of wood smoke particles allows them to easily penetrate into homes, at rates up to 88% as high as outdoors. And if you are the wood burner, what goes up your chimney, quickly seeps back into your own home.
A California study showed some people are breathing 2,500 times more pollution than others in the same monitoring zone. One of the main reasons why is wood burning. Dangerous and oppressive pollution in China has received widespread media attention of late. But here in the United States, the rest of your community can be enjoying clean air, but if your neighbor is a wood burner you can be living in a different universe, breathing a level of pollution that would make Beijing, China seem like a breath of fresh air.
The term “intake fraction” describes perhaps the most underrated consideration in assessing the health impact of various pollution sources. It refers to the percentage of pollution emitted that is actually inhaled by humans. With wood smoke, given the above factors, the intake fraction is extremely high, much more so than virtually any other pollution source.
Wood boilers deserve special condemnation as they can emit truly shocking amounts of pollution, and simply should be banned in all but the most remote locations. Levels of particulate pollution measured 50 ft. away from a boiler can spike to 880 times the level that the World Health Organization considers acceptable long term exposure. Even at 150 feet away, spikes frequently occurred at 50 to 100 times that “acceptable” level.
Once the health hazards of second hand cigarette smoke were firmly established, sweeping ordinances throughout the country were passed to protect people from second hand cigarette smoke. Scientifically we are at that stage now with wood burning. We don’t prohibit smoking in public venues because of what it does to levels of atmospheric community pollution. We do so because no one should be forced to breathe someone else’s cigarette smoke. For all the same reasons, no one should be forced to breathe someone else’s wood smoke.
Moreover, replacing old stoves with new “certified” stoves is no more a solution than putting filters on cigarettes was a solution to the plague of smoking. Stove change out programs are merely money making schemes for the Hearth and Patio and Barbecue Assoc (HPBA). The performance of “certified” stoves in the real world, outside the laboratory, are no where near as clean as certification suggests.
It is a common misconception that burning wood is carbon neutral and therefore less of an impact on the climate than fossil fuels. This has lead to poor public policy in both the US and Europe. The amount of carbon released per unit of energy produced is actually greater for wood than it is for fossil fuels. Moreover, burning wood releases carbon now when we can least afford to do so, carbon that would otherwise have been stored for decades or perhaps centuries. While sustainable forestry practices can help repay that “carbon debt” eventually, those benefits do not accrue until decades into the future, far too late to be of much help. Considering the entire carbon life cycle of wood, we should look at wood burning with as much antipathy as fossil fuels.
Gov. Herbert’s proposed ban on winter time wood burning never made it into public policy, the HPBA made sure of that. They stoked up the “my right to burn, trumps your right to breathe” libertarians, made sure the public hearings became a parade of “burner” outrage, flew in hired guns from California, paid for an expensive lobbyist, and the legislature did what they do best, caved to special interests.
The first step in defeating the HPBA is lifting the veil of ignorance. Here is a brief message to share with your wood burning neighbors. If you are not a smoker, burning wood is probably the greatest threat to your own health of anything that you can do. But it is also a threat to your children and your neighbors, as inappropriate and intolerable as blowing cigarette smoke in their faces all winter long. Your neighbors are less than enthusiastic about sacrificing their health for your freedom to burn wood. Living in a civilized society means they shouldn’t have to.
Dr. Brian Moench of Salt Lake City, Utah is President of Utah Physicians for a Healthy Environment; member of Union of Concerned Scientists; member of radiation and health committee, Physicians for Social Responsibility; former instructor at Harvard Medical School; and former adjunct faculty member at University of Utah Honors College, teaching public health and the environment.