Today, though, we’re going to home in on just this one issue of upgrading to a filter with a higher MERV rating, a filter that can remove more of the small stuff. (And if you’re not, the Awair Element* is one of best, and most affordable, IAQ monitors for homes.*) You may know this already if you’re monitoring your indoor air quality. The chart shows that to remove at least 85% of the PM2.5 from the airstream, you have to use a MERV-13 filter.* Of course, you should read that whole article because I also talked about a lot of reasons why you may not be getting the filtration you think you’re getting.

It shows the percent of different size particles trapped by filters with different MERV ratings. After my article on indoor air pollutants, I wrote about filters and even included a nice chart from my friend John Semmelhack. As it turns out, the PM2.5 particles can be filtered out of the air with the right type of filter. And that was the point of my article on which indoor air pollutants are of most concern.īut you’re in luck. Like deep into your lung tissue, where it can find its way into the bloodstream. The size is important because really small things can get into places that bigger things can’t. Fine particulate matter is also called PM2.5 because it’s the same size as that superfine hair sliced in half three times. Last month I wrote that fine particulate matter is the really bad stuff. That also happens to be the size of particulate matter that causes a lot of indoor air quality problems. Whatever units you use, though, it’s a really small size. If you must, that would be about 0.0001 inch. Now you’ve got a sliver of hair that’s 2.5 microns wide. Then take one of those halves and slice it in half again…and then one more time. What is a hair’s breadth? A strand of the finest human hair is about 20 micrometers (also called microns) in diameter.

Merv 10 vs 11