Obviously, don't go out, keep windows closed, limit activity.

To the extent you can, (and still be safely cool enough) limit air conditioning. Depending on how it works, the system may "think" it's bringing in fresh air.

And I'll guess, this is a bad time to 'skip' using your CPAP.

HEPA air filters take out a =lot= of particulates (but not gases.) Even a small HEPA will likely help you. For gases, we need a separate kind of filter (carbon something...)

Talk to your doctor, s/he may be able to write you an Rx for same, and reduce your costs if you buy one.
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My Amazon trick is to join Prime to get free and/or fast delivery, and then (important!) =un-join= Prime before they make me pay for it.

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Number One thing I learned working for the USA Federal Emergency Management Agency is: Never ignore an order to evacuate.

Wildfires can be =fast=. They are driven by the wind. And wildfires can 'jump' with blown sparks and embers. Too many people have had their escape cut off by a 'jumping' fire.
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Number two is: Never enter water. That calm 5 cm of water on the road you know ... Your road may have been cut away to a depth of 3+ meters.
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Long and "geeky": https://en.wikipedia.org/wiki/HEPA