The most dangerous wildfire smoke is at altitude

 However, when homes are burning the carpets if they are synthetic materials and not wool are cancer causing when they burn. The same is true of non-leather couches and sofas too. So, if you are in the middle of a lot of homes burning the smoke could make you very sick, cause you to get cancer or worse.

However, in regard to breathing and staying alive in the moment the most dangerous wildfire smoke is at altitude.

I have told this story before but it is true. Most people live around sea level or not too much above that (usually under 2500 feet  unless you live in parts of northern Arizona (Flagstaff is at 7000 feet, Grand Canyon on top of the south wall I think is at least 6000 feet in elevation and Santa Fe, New Mexico is over 7000 feet in elevation as well as Coloradoo Springs, Colorado. Even Albuquerque is around 5000 feet and even Winslow Arizona is well over 4800 feet. Many people don't realize just how high above sea level northern Arizona and Northern new Mexico is.

However, my wife and youngest daughter and I went to Lake Tahoe in our motor home and rented a Chalet to stay in for one or more nights there. However, there was a fire next to the Chalet so I refused to carry our luggage up three flights of stairs because I had already lived many years in the past before I met my present wife in Mt. Shasta going through wildfire smoke at altitude.

She got mad at me for not unloading the motor home and wouldn't listen to me and started carrying our luggage up 3 flights of stairs. I0 hoped she would be okay but she is a very strong willed and intelligent woman.

So, basically she got smoke inhalation and we had to get a fireman to give her oxygen and then an ambulance came and she had to spend the night in a hospital in Truckee (the nearest large hospital to lake Tahoe where we were staying. )

The point is if there is a fire when you are at altitude don't do anything physical if you are breathing this smoke in and don't have any other choice or you might wind up in the hospital too or die from smoke inhalation.