In most homes, a Merv 11 filter is sufficient to maintain a healthy environment. However, if someone in your household suffers from allergies, you may want to consider upgrading to a Merv 13. This could be due to pet allergies, pollen allergies, or even mold and dust allergies. If you have allergies, pets, or live near smoke pollution, a Merv 13 filter is the ideal choice.
But if you simply need a filter to trap pollen, dust mites, and hair, a MERV 8 filter should do the job. According to Avery's point, a new construction makes it easy to accommodate a high MERV filter with no static pressure penalty. For example, I am wearing a layer of MerVi and using a layer of Merv 1900 3M Filtrete on my mask (I made the mask as a cover so that I could remove the filter to wash it). If you want to use pleated filters and superior MERV filters, the only safe way to do this is to have a 5-6 inch media filter installed by a professional.
Air filters of different sizes will have different prices, the same goes for the MERV rating of the filter. A HEPA filter is the ultimate solution in the air filter world and far exceeds what a MERV 13 can do. If your home's HVAC system is not capable of handling MERV 13, opt for a filter with the next highest possible rating. I recently published an article on using high MERV HVAC filters in homemade coronavirus masks.
While air filters with a MERV of one to four are effective at removing large particles such as carpet fibers, airborne paint droplets, and sanding dust, they cannot help with contaminants such as hairspray, mold spores, or even flour that could have escaped from the mixer. A MERV 13 will trap less than 75% of air particles that are 0.3-1.0 microns in size (coronavirus is 0.1 microns). The Merv 16 would be the best option since it will filter 95%. There is also a YouTube video that shows how to make your own N95 with a Merv 16 filter.
While MERV 8 is known to be effective at filtering contaminants such as pollen, dust mites, sawdust, mold spores, and lint from the air, higher Merv ratings will clean the air even more.