I just called an HVAC company and there's a product known as a Heating Recovery Ventilator that pulls fresh air in, exchanges heat with the outside air coming i

I just called an HVAC company and there's a product known as a Heating Recovery Ventilator that pulls fresh air in, exchanges heat with the outside air coming in, and passes the incoming air through a filter. The filters however were not designed with the expectation that the air be full of smoke. They do offer some amount of filtration however. The store apparently stocks Fantech products. There's also these grow room products that have fan and filter combinations such as https://www.homedepot.com/p/Viagrow-6-in-Carbon-Air-Filter-with-Inline-Fan-Combo-V6CF-KIT/203554119 https://www.homedepot.com/p/Viagrow-6-in-Carbon-Air-Filter-w... This fella creates a DIY window based intake filter from a furnace filter, an air conditioner prefilter, and some other charcoal prefilter mesh http://www.air-purifier-power.com/windowfanfilter080515.html http://www.air-purifier-power.com/windowfanfilter080515.html. It apparently works well for everyday dust but is unknown how it stacks up against smoke. There's also this product much in line with the above DIY project Activated Carbon Passive Window Air Purifier https://www.homedepot.com/p/Activated-Carbon-Passive-Window-Air-Purifier-AC-736/206173822 https://www.homedepot.com/p/Activated-Carbon-Passive-Window-... There's some airbox inline filter design too such as this unit https://airboxfilter.com/Airboxfilters/air-box1 https://airboxfilter.com/Airboxfilters/air-box1