2. Decibel tests - to determine the quiet levels of the machine
3. Smoke tests - to determine ability to remove cigarette, fireplace and cooking smoke
4. Bacteria, and mold tests as available
5. Independent tests from outside sources
6. Consumer feedback
7. Hands-on dissection (video)
8. Replacement filter costs - to determine the value and economy of an air purifier over time
I've tried to include as much of this data as possible on this site, including particle tests that we perform in real world situations.
Our overall air purifier ratings system is calculated by:
1. Technologies Included
2. Particle Removal (Allergens, Dust)
3. Immune System Threats (Germs, Virus, etc.)
4. Gas Removal (Odor, Chemicals, Smoke)
6. Noise Levels
7. Ease of Use
9. Customer Service/Reputation (reviews)
10. Price Value
At the end you'll find Questions and Answers from readers and from online reviews as available.
For all my reviews I try to include a particle test because it's the only way to really know a machine removes dust and pollen. It shows that air purifiers really work. The only drawback is that it doesn't show how it does on germs, viruses and gases. There are other tests for those. But if pollen allergies are your problem it must test a particle test.
Also - Particle tests need to be done two ways: 1) on the outflow of the air purifier to determine if it is removing all molecules and 2) from across the room over a 1-2 hour period to determine if the air purifier is effective at lowering the numbers to near zeri.
P.S. if you don't know the 10 technologies available and what they do go to the home page and watch the "Guide To Air Purifier" video first.