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Here is another HEPA air filter manufacturer with added carbon filtration. This was recommended by my doctor. They are expensive, but do a great job of removing particulate and VOCs from the air. I have the larger rectangular one with an added UV light inside. It's filters are easy to change, and there are filters on the air intake similar to a furnace filter that are changed regularly to keep the HEPA/Carbon filters inside working longer (for a few years). The filter for this is a metal box with 2 stages inside made by the manufacturer and is not user serviceable. You replace that box filter unit.

I also have the cylinder type model which has an inch of carbon media around the inside surface of the cylinder, and then a HEPA felt blanket on the inside as the air gets pulled through it to the center and out the top. It doesn't have automatic on/off or air monitoring. I do repack those myself only outside because the media is dusty when you take it out of the bag, and the HEPA felt caches any residual carbon during use and particulate in the air. There is a metal strap spring holding pressure inside the cylinder to keep the felt in place. It does have some sharp corners, so I handle it carefully. This is similar to the carbon filtration used for aquariums. You can also buy prepacked cylinders and send back the used one for credit. Those need to be changed every 6 months to a year, but that may depend on how dirty the environment is and how often it is used. I run this in my bedroom at night and turn off during the day because I have the larger unit on the main level of our home that is run all the time except when we leave. When I travel, I take the cylinder unit with me, but it is a bit large for that. There is a smaller version for the car, but without as much filtering capacity. I have used mine for a year or more before changing media and filter. You can add a fabric cover on the outside of the cylinder that they sell, but I had a unit motor stop working after that. I have had these units a long time 10 to 15 years, and only had a problem with one. The motor is a heavy industrial type and everything is metal. There is no plastic or glues used in manufacturing to outgas for sensitive people. Made in the US.
https://foustco.com/