The instruments we used to test these machines are capable of detecting particles as small as 0.010 micron, which is far below the threshold for civilian equipment and below the 0.3 micron threshold for the HEPA standard.
What follows is just a summary of our findings, but for those who are interested in learning more, the How we tested section of our full review includes our procedures, methods, and results, complete with tables and graphs of our results.
The thin 3/16-inch activated carbon filter is just not up to the task.
If you have severe allergies to particulate allergens or other health issues related to air quality, or you re willing to pay a premium for a machine that can be extremely efficient while running quietly, we recommend our upgrade pick, the Blueair 503 with the SmokeStop filter package.
In our noise-limited tests, it removed more than 90 percent of the particles from our bedroom-sized testing area in 10 minutes—that s over 10 percent more than the next best purifier and over 60 percent more effective than the control.
Its exceptional performance in this area is a big part of why FEMA and the Red Cross chose Austin Air units for deployment at Ground Zero and the surrounding areas in the aftermath of 9/11.