As a coach, I’m often asked about training in poor air conditions. I’ll be honest with you, I love my lungs. I’d like to have maximum lung capacity for as long as possible in my life. I’ve also got a lifetime history of respiratory illness, so I may be more conservative than others, but here are my guidelines.
I monitor several different AQI sites. If AQI is 100 or more, I will not train outside. I may walk, but I will not run or cycle. If AQI is 150 or more, I also won’t train inside. Our buildings are not airtight. Unless you have a HEPA system in place, small particulate matter is in your home. It’s also in your lungs.
Given that COVID-19 is a virus that also affects our lungs, I think it’s even more important to be conservative during bad air days. There is no medal for training in dangerous conditions. Linked is an article I found interesting about poor AQI and COVID-19.
https://www.mercurynews.com/2020/08/20/wildfire-smoke-or-covid-19-which-is-making-you-sick/
Please, monitor AQI. The pollutants in wildfire smoke include not only wood smoke, but paints, metals, freon, and other household and industrial chemicals. The sky/air may appear clear (as it does at my house right now even though the AQI is almost 200), but the SMALL particulate matter, the PM that damages your lungs, could be very high. Visible smoke is an indicator of LARGE particulate matter. Your mask will filter that out. Your cloth mask will not filter out the SMALL particulate matter.
How do I monitor AQI? I monitor several sites, but my favorite is http://www.purpleair.com