When working out indoors do you have a HEPA air filter on?
Been learning about 2.5PM air pollution particle levels which is monitored on sites like crowd-sourced sensors www.purpleair.com. These tiny air pollution particles are absorbed into blood stream via lungs. The faster and deeper you breathe, the more you can absorb into your body. They deposit in lung and other organ tissues.
The lower the 2.5PM pollution index, the better.
So months ago I started using a good quality HEPA& charcoal air purifier in my workout room. I also found a YouTube video about making an air purifier with a typical 20-inch box fan + Merv13 or higher-grade furnace-type filter that is secured to the intake back of fan. Together, the air circulates well. My indoor air pollution sensor shows my 2.5PM is steadily under 5 (that’s good).
When I checked the box fan filter, it is starting to look blackish from capturing air debris particles.
I stopped doing vigorous exercise outdoors when my local air pollution index on www.purpleair.com is over 50. I really prefer under 25.
Sadly, I know a few people who have been diagnosed with lung cancer under 60, one of them under 50. No smoking or 2nd-hand smoke exposure, no occupational factors, no family history, no Radon detected at residence. Couple were avid outdoor runners. But admittedly had no concern for air quality outdoors even though they live in dense car traffic areas.
Be safe.