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New Study: Current Particle Pollution Standards are Killing Us

For years, scientists and medical professionals have cautioned that the US standard for fine particle pollution is set too high to effectively protect human health. In the winter, wood burning is one of the leading contributors to particulate pollution.

A large European study recently published in the Lancet gives new credence to these claims. Notably, the European Union fine particle limit of 25 µg/m3 is already considerably more protective than the US standard of 35 µg/m3.

What this study shows is that even the lower EU standard is not low enough to adequately protect human health.

The study’s lead author Rob Beelen notes, “Our findings suggest that significant adverse health effects occur … well below the EU annual average air-quality limit value of 25 µg/m3.” Results from the study showed that the risk of natural death increases by 7% with each 5 µg/m3 rise in PM2.5 concentrations.

This large study looked at data from 22 European cohort studies conducted in 13 European countries to investigate the link between natural-cause mortality and long-term exposure to air pollution. Almost 370,000 participants were monitored for an average of 14 years. Note that the analyses controlled for socioeconomic, health, and lifestyle factors such as income and smoking, which are known to influence mortality.

According to Beelen, “The World Health Organization air-quality guideline is 10 µg/m3, and our findings support the idea that significant health benefits can be achieved by moving towards this target.”

This study brings new urgency to the need to lower the fine particle pollution standard in the US. Also, given the fact that in many communities wood burning is the largest source of wintertime fine particle pollution, the study makes it clear why it is so important to eliminate wood burning pollution.

Wood Smoke Pollution: A Personal Story

Families for Clean Air receives letters all the time from people suffering because someone nearby burns wood. Although it is important to publicize studies and statistics about wood smoke toxicity, we wanted to print this letter as a reminder that when someone burns, they are hurting their neighbors.

The letter reads:

“My neighbor, who lives in very close proximity to my house, has been burning wood in an indoor stove every “Spare the Air” [burn ban] day this season. He routinely burns at night, which is the most difficult for us. My daughter’s room, bathroom, and our living room are virtually uninhabitable due to smoke leakage into the house. I have taped all windows and doors adjacent to the neighbor, have 3 freestanding air filters going in those areas all the time and last year installed a house-wide air filtration system and new furnace ($12,000). I also push towels under some of the doors. I cannot keep this smoke out of my house, which is well-built, well-insulated, and has double-pane glass windows throughout.

I am an asthmatic and have no quality of life right now. I have had to increase my medications, and my last med bill was $1000, which will only take me until January. Sometimes, I awake with burning eyes, throat, and chest pains because the smoke is in my bedroom. Night before last, I awakened at 2:30 a.m. to a smoke-filled house and was up until the following night trying to clear the air. Once the smoke is in, it is almost impossible to get rid of it. Obviously, I cannot open any windows.

I would like to point out that this is not a case of a burning cigarette, it is a massive amount of wood, possibly not properly cured, polluting my home and endangering our health. We have been suffering for the entire 11 years that I have lived here. I have made numerous contacts with the neighbors, requesting them to comply with regulations, not to burn with opacity and not to burn on Spare-the-Air days. I also signed them up to receive the Spare-the-Air alerts…

I work at home so there is no respite. Any assistance in this matter would be greatly appreciated.”

Wood Smoke Pollution Kills More than Two Million People a Year

Here in the US, most of us don’t get exposed to extremely high levels of wood smoke inside our homes. But just like studying the lungs of two-pack-a-day smokers tells us about the harms of cigarette smoking, studying the effects of exposure to high levels of wood smoke tells us about the many ways that wood smoke can harm our health.

And what it tells us is not good.

When families in developing countries burn wood and dung in their homes for cooking and warmth, the fires produce levels of pollution that lead to the premature deaths of about 2 million people each year, more than either malaria or tuberculosis.

This disturbing news is discussed in a 2012 interview with Dr. Kirk R. Smith, a member of the National Academy of Sciences and Professor of Global Environmental Health at the University of California at Berkeley. Dr. Smith has spent decades studying the health effects of indoor air pollution due to biomass burning on women and children in developing countries.

Dr. Smith notes that there are parallels between the dangers of cigarette smoke and wood smoke. “Most people recognize that the worst thing you can do is stick burning stuff in your mouth. The second worst thing is to have burning stuff inside your house…”

According to Smith, “A fire in the kitchen, if you’re cooking a meal, produces about the same pollution per hour in a typical house as a thousand cigarettes burning. So, if you think about a thousand cigarettes burning inside your kitchen, it’s not surprising that there are significant health effects. The big difference is that children and babies don’t smoke, but they are in kitchens and are also being exposed to the household pollution, so there’s a large impact on children.”

Smith’s research focuses on interventions in developing countries to reduce the harm from wood smoke. Unfortunately, despite many programs that have introduced supposedly improved stoves, these programs have not been effective.

Smith explains, “…those stoves don’t get rid of the smoke, they just move it around. What you have to do now, I believe, is eliminate it; don’t produce the stuff in the first place.”

For more information about the effect of wood smoke in developing countries, see When Smoke Gets in Your Lungs.

Beyond Particulates: Toxins in Wood Smoke

In many areas, wood burning is the largest single source of particle pollution in winter months.

But what about toxic compounds?

A recent study by the Australian EPA sheds some light on this topic, and it’s an eye opener. For example, look at formaldehyde, which is a potent irritant and carcinogen. The study found that in the Sydney region, 38% of the formaldehyde in the air is generated by residential wood heaters.

Another example is polycyclic aromatic hydrocarbons (PAHs), which also cause cancer: 35% comes from wood burning.

Perhaps most frightening is the data for dioxins and furans, which are some of the most toxic compounds known to man–39% is generated by wood burning.

These numbers are even more troubling when you consider that they are annual figures and that wood burning in the Sydney area takes place for only about a third of the year. During the winter months, residential wood heaters likely account for more than 50% of these toxic compounds in the air.

Before you breathe a sigh of relief that you are not living Down Under, bear in mind that wood burning activity in the Sydney area is not any worse than in many areas in the United States and around the globe.

To date, attention has focused mainly on wood burning as a source of particle pollution. This study makes it clear that wood burning’s role as a source of toxic and carcinogenic compounds may pose an even greater threat to human health and to the environment.

Wood Burning vs. Natural Gas: No Contest

Families for Clean Air recently received a letter that asked for references backing up our assertion that the emissions from EPA-certified wood stoves are greater than those from devices that burn natural gas. This information is available from many sources, including the US EPA, but we think the chart below from the Puget Sound Clear Air Agency illustrates the point in a clear and simple manner (you may click on the image to enlarge):

Wood Smoke Particle PollutionAs bad as this chart may make things look for wood burning devices, we’d like to note that it actually makes the relative performance of wood burning stoves seem more favorable than it actually is. First, the emissions of wood burning stoves are tested under laboratory conditions that bear only a passing relationship to how they are likely to actually be used in the real world. Second, studies have shown that the performance of EPA-certified wood stoves can deteriorate over time.

Thus, the wood stove data probably reflect ‘best case scenario’ stove performance in laboratory conditions.

Any way you slice it, it’s clear that gas burns much more cleanly than wood, leading to less particulate pollution.