Just when we thought we’d dodged smoke season, the smoke has arrived. When the smoke rolls in, we get a lot of questions and comments about exercising outside. We hear everything from “is it safe to run?” to “are there masks I can wear?” and “I’m going outside no matter what!”. There is a seemingly endless supply of resources online to help you make a decision about whether or not you should exercise when the air is filled with smoke. Unfortunately, there is not a clear scientific consensus on the exact effects that exercising during smoky weather has on our bodies. And, there are maybe too many worm holes you can go down finding out about where smoke is coming from and trying to predict if it will get worse. Here, we’ll try to give you the resources you need in order to make an informed decision for yourself about exercising during wildfire season and our favorite tools for tracking the smoke!

First off, what pollutants are we concerned about?

With smoke comes fine particulate matter. The particulate matter we’re mostly concerned with as runners and walkers is PM2.5. The Air Quality Index (AQI) is made up of several pollutants, but it does a good job of capturing the PM2.5 value, as it is our primary pollutant during smoke season. The more PM2.5, the worse the air quality!

A light layer of smoke over the Missoula Valley. Still good enough air for a run!


How do you track the AQI?

You can find a measure of the AQI on your phone’s weather app or with a quick google search. A heads up, the AQI listed on the iPhone weather app is often slow to update (I have seen it read “unhealthy for sensitive groups” when in-town sensors have read “good”). A great resource for tracking AQI is the Today’s Air page from MT DEQ.

Where is the smoke coming from and what’s it going to be like tomorrow?

If you’re looking to understand where the smoke is coming from, why it’s in Missoula (or your area), and when it might go away, you need to do a bit more investigating. Thankfully, the Missoula County Public Health Department maintains a daily discussion on air quality. Here, not only can you find the AQI and health recommendations, but you can also find a discussion about the air quality, fires, smoke, winds, and more. Written by a real live human, this discussion is an indispensable resource for understanding the current smoke situation. A lot of us at the store are huge fans of the air quality blog. I mean, HUGE fans. These discussions are written by Health Department Air Quality Specialist Sarah Coefield. Thank you Sarah for diligently providing our community with the best information available!

Want more? Here’s that wormhole I was talking about…

Finally, should you run when it’s smoky out?

Heavy smoke obscuring the sun – don’t run in this!

Ahhh, we had a feeling this question would come up. We get this a LOT. Unfortunately, there is no straightforward answer. In the words of Missoula County Air Quality Specialist Sara Coefield during a former blog post, “the answer is a very unsatisfying ‘it depends.’ Human health is a spectrum, yo.” 

Run Wild Missoula references the Missoula County Outdoor Activity Guidelines Based on Air Quality to determine if their groups runs, training classes, and events should be held. If the air is Good, Moderate, or Unhealthy for Sensitive Groups, events will continue. However, depending on your medical background, running or walking may not be a good idea. If the air quality is Unhealthy, Very Unhealthy, or Hazardous, events will be cancelled. We agree! If the air is Unhealthy or worse, the risk of exercising outdoors outweighs the benefits.

Missoula County has a great chart that lays out different activity types and what duration might be ok at various air quality levels. It is definitely worth checking out!

What if I REALLY want to run or walk outside when the air is terrible?

Short answer, you would likely be better off staying indoors in clean air. BUT, there may be ways to get outside and stave off that pesky particulate matter and the nasty effects it has on your lungs. If you have an N-95 mask laying around from the pandemic, now is the time to whip it out again. These aren’t just masks, but are “particulate respirators.” Your cloth mask won’t do the job against wildfire smoke. Only a PROPERLY FITTING N-95 offers enough protection to run during terrible air quality. This means you need to be clean shaven and ensure a perfect fit. More on that here. Remember, you have an N-95 on. So it’s also very hot and muggy in there. If your mask gets wet, crumpled, or compromised in any way, it will stop filtering out particulate matter. Be sure to replace them frequently! Again, you are most likely best off avoiding the outdoors when the AQI is Unhealthy or worse. But if you insist on going outside, wear a properly fitting N-95.

A slight smoke haze obscuring the distant mountains in southwest MT

So if I run inside on a treadmill I’m fine?

Maybe! Be sure that the air where your treadmill is has been properly filtered. Find a high quality HEPA air filter and keep it running while you’re on the treadmill. Or, try a less-expensive do-it-yourself version that uses just a box fan and simple air filter. Climate Smart Missoula has directions for this easy DIY project here.

Stay safe this smoke season! Hopefully we’ll be breathing cleaner air soon 🙂