Exercising During Wildfire Season

by Eric Sharpe

The east coast has hurricanes.  The west coast has earthquakes.   The Midwest, tornadoes.  Such events are quick and often headline getting.  Advance warnings and advances in construction now save countless lives.


The High Plains and Rocky Mountains have forest fires and wildfires… as does every other state in the union. In fact, in 2016, every state except Delaware dealt with a wildfire.  But in the Northwest, the vast commodity of forested acreage in .  Such a threat just doesn’t seem as threatening as other natural disaster, at least, to those who’ve never directly experienced one.


But even those who indirectly experience one by way of viewing a hazing morning sunrise are unaware of the dangers they pose.  Smoke from wood and grass is not just a simple release of water vapor and carbon based material.  According to the EPA, wildfire smoke is a mixture of carbon dioxide, carbon monoxide, particulate matter, and nitrogen. And depending on the type of material, such smoke contains various levels of

“lignin, tannins and other polyphenols, oils, fats, resins, waxes, and starches.”  Acrolein and formaldehyde are also present though in lesser concentrations.  The nearer the source of the wildfire, the higher the concentrations of these chemicals, which is an obvious statement, but the obvious nature of it hides the dangers of being tens if not hundreds of miles away.


Over 67,000 wildfires (which is a catchall for grass and forest fires)broke out across the United States in 2016 burning 5.5 million acres – about the size of New Hampshire.  And 2016 wasn’t even considered a bad year for wildfires. In 2015, over 10 million acres burned.  The four states most affected by forest fires over the past decade are western states that were experiencing drought conditions: Idaho, Oregon, California, and Washington, though in 2017 (as of August), Montana held the number one spot.


Health hazards are obvious to those suffering respiratory ailments such as asthma and COPD, but for those who spend a great deal of time in the great outdoors, especially running or engaged in other exercise activities, the dangers are hidden, and potentially severe.


The most stressing aspect of wildfire smoke on the lungs is particulate matter, which is “particles suspended in the air, typically as a mixture of both solid particles and liquid droplets.”  Such material is so small that it floats in the winds until finally settling to the ground, sometime up to days later, or until they find their way into someone’s lungs.

Particulate matter is measure in size by “microns”, aka micrometers.  The width of a human hair is about 100 microns.  Particulate matter (PM) from wildfire smoke


A micrometer, commonly known as micron is one millionth of a meter, one thousandth of a millimeter or one thousand nanometers. A strand of human hair is between 50 and 100 microns.  Particulate matter measuring larger than 10 microns (PM10) usually don’t reach the lungs.  Anything below flows right in. Wildfire PM can be as small as 0.4 microns (near the wavelength of visible light) which reach the deepest areas of the lungs.  Worse, PM has various shapes as well, with some being categorized as “coarse particles” having sharp microscopic edges.  It is much like microscopic ground glass.



Montanans must especially be cautious as the fire season is part or our annual experience:  July brings intense heat without relief of rain. Then comes the dry thunderstorm provided lots of lightening but no rain.  Then the dry strikes by lightening in remote areas.  August brings the smoky haze.


Exercise and Wildfire Smoke.

No amount of particulate matter is healthy but as the height of the fire season hits in August, Montanan’s, especially those whom exercise outdoors (and groups sensitive to poor air quality) need to start paying attention to the skies.


A simple visual check of the skies though is not the best way to determine air quality, but as a rule of thumb, if you can’t see the hills across the Yellowstone River from the Rims, the AQI is considered “Unhealthy.”  The best measure is the AQI, or the Air Quality Index.  It reports smoke monitoring across the country and can be checked at either the EPA’s airnow.gov website or at Montana’s own http://svc.mt.gov/deq/todaysair website.


For a runner dedicated to a daily routine, rain, sleet, snow, cold heat… all can be tolerated… but dangerous levels of smoke present a situation where that dedication to an outdoor workout must be balanced against common sense. The generic paper face mask (like a dust mask or surgical mask) are of absolutely no use in filtering out smoke, besides, wearing one blocks respiration… bad idea.


The AQI list and related dangers is listed below.  Even on “Moderate” AQI days, it is generally not a good idea to be outside exercising. The bad news… every August, Billings air quality tends to fall in the Moderate range.  Indoor gyms or you own home will filter PM some extent as air conditioning filters handle some PM improving overall AQI making it relatively safe to exercise on “Moderate” AQI days.  Even USG days, Unhealthy for Sensitive Groups, is relatively safe for an indoor workout.  But once this AQI hits stay away from outdoor exercise.


According to the EPA, “In homes without air conditioning, indoor concentrations of fine particles can approach 70 to 100 percent of the outdoor levels.”  But even though most of us have AC, generally speaking, though the cloud of smoke is not going to invade your home, smaller PM will as generic AC filters are usually only filter out particles that are 10 microns or larger.  If you are serious about exercising indoor during an unhealthy smoke day, they do make filters than knock out as small as 0.3 microns.  Remember, wildfire smoke can contain PM of as little as 0.4 microns.  Air conditioning and heating filters quality to filter out PM is based on the MERV scale (Minimum Efficiency Reporting Value) The best filters have a MERV rating of 17-20 which capture PM that are less than  0.3 microns. Generic filters are rated at 1-4, capturing only 3-10 microns.



The effects of smoke range from simple eye and respiratory irritation to rather serious issues including breathing problems and the exacerbation of asthma and heart conditions.


The deep heavy breathing during a long run or outdoor activities which bring more concentrations of PM into the lungs may not immediately reveal health problems.  But as the lungs continue to cope with fine shards or particulate matter, headaches, coughing, phlegm, wheezing and general difficulty breathing will take place.  Serious symptoms include nausea weakness, dizziness, confusion and visual impairment.


You are not invincible, no matter how healthy you are.  And if you truly care about your health, pay attention to the AQI before any outdoor exercise routine during the summer months.

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