Feb 5, 2018
by Gary Pace M.D.
During the fires, the question came up regularly: “How bad is the risk from all of this smoke, and is it long-term?” Also, recently a major medical journal stated that there are 20 million premature deaths a year worldwide due to air pollution. While US ozone levels and pollution have improved over recent decades due to government regulations, the Trump administration is now cutting funds to the EPA and gutting protection for air quality.
Understanding exactly what is happening to our health when confronted with smoke or air pollution will help us to better assess the risk and how to protect ourselves. In fires, the acute risk is from smoke inhalation which kills by a combination of heat, poisoning and pulmonary irritation. In chronic exposure to air pollution, the WHO estimates that 2/3 of outdoor air pollution-related premature deaths were due to heart problems, 14% were due to lung problems like emphysema or infection, and 14% of deaths were due to lung cancer.
Children, pregnant women, and elderly are especially vulnerable to problems from smoke exposure. Smoke has many different components, but particulate matter is the major player. These are the small particles suspended in the smoke, and the size of particles affects their potential to cause health problems. The larger particles don’t make it down into the lungs, but they can irritate the nose and throat. Smaller particles, less than 10 microns, can get deep in the lungs and cause cough, phlegm, and breathing problems. An N95 respirator when properly fitted is supposed to be able to filter out 95% of the particles smaller than 3 microns.
Carbon monoxide is a toxic byproduct of fires, but the concentrations typical of exposures related to wildfire smoke do not pose much of a risk. At higher levels (such as those that occur in major structural fires), carbon monoxide can cause some sensitive individuals and people very close to the fire (like firefighters) headache, weakness, and even death.
An understandable concern after the fires is about any increased risk of cancer or of development of other chronic health conditions (e.g. heart disease) from the relatively brief exposure to wildfire or building smoke. There can be many cancer-causing compounds in the smoke, depending on what is burned, and people may have slightly increased long-term risk for cancer, but in general, these risks from short-term smoke exposures are thought to be quite low.
The Sonoma County Health Department has information on current air quality levels and links to the Bay Area monitors: sonomacountyrecovers.org/ and click on the Air Quality button. Reports immediately following the fires showed that the Air Quality index rose to over 200 (very unhealthy), when less than 50 is considered safe. This dangerous level cleared for most areas within the week.
Now the main health issue centers around air quality impacted by debris removal for people living and working nearby. This is being watched by the health department and the EPA, and they generally feel that things are reasonably safe. There have been some concerns that some contractors have not provided adequate protective equipment for some of the workers, but that has been addressed. Certainly, when working in an area that was burned, it is wise to use respiratory protection, because as the dust gets agitated from the cleanup, more particulate matter can be inhaled.
Steps to Take in Case of Future Fires (decrease inhalation of particules)
● Particular caution with sensitive groups (children, elderly, people with chronic health issues)
● Stay inside
● Avoid strenuous activity
● Reduce other sources of indoor air pollution
● Use N95 Disposable Particulate Respirator when needing protection
● Use air cleaners and filters, but avoid ozone generators
● Follow reports on the websites.
Conclusions: Chronic air pollution exposure is an important concern. Some recent studies have shown important shortening of lives worldwide due to exposures. Acute inhalation, such as those from the recent fires, are thought to be reasonably benign for most people, but taking appropriate precautions is probably a good idea. Looking at the Health Department websites or at Bay Area (BAAQMD monitoring information can help determine current risk.
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