Idea to filter forest fire smoke for my CPAP

Hello all, I have a problem, I live on Vancouver Isl B.C. and last year we had a VERY bad forest fire smoke issue. Fires from the BC interior had smoke blanket the area for weeks. I also have bad asthma and I am still feeling the effects of that time last summer. As we approach the season once again I don't want to get caught with the issue again, so I have purchased a respirator for daytime use. But at night I will still have my CPAP pushing air that it BARELY filters into me. Forest fire smoke is .3 to .7 microns in size, HEPA filters should handle most of that.

So to my idea, I was thinking of taking a sealed Tupperware like container that can fit my resmed airsense 10 into it, drill a hole for the hose, use a coupler and a short hose as an airtight link. Then cut a hole in the top of the box and fit a HEPA filter as an air intake for the box. Some creativity to make sure its air tight on the filter seals of course.

With this plan tho I am wondering if there are some drawbacks that others might see. Could the negative pressure that will exist in the box have effect on the treatment? Will the resmed airsense 10 simply automatically dial up the pressure to compensate like I think it will?

Thanx :)

Sounds complicated. You are correct though about smoke being a particulate and a fine filter will take it out. I think I would just buy the Hypoallergenic filters that ResMed makes for the machine. See this link for a supplier in Canada. I have dealt with them and they are very good. You probably would have to replace them more often than the standard filters. And if you think it is bad on Vancouver Island, you should try it in Alberta. We are downwind of all that smoke!

It occurs to me that your whole house and entire day are affected by the smoke, and focusing on sleep may be a third of the issue. We have a room HEPA filter for the living space that seems to reduce the infiltration when we have unwanted air quality. But perhpas you have already done that.