Here is a video which explains the pros and cons of HEPA filters, along with some of the problems in the HEPA air purifier industry
I thought it was all in my head.
I always seemed to sleep better, more rested, and wake up with a lot of energy whenever I left my air purifier on all night. Well, it turns out that one of the technologies in the machine (AliveAir Machine) actually has some good science behind it that may help in overcoming sleep disorders. It might even help people who use sleep pills, insomnia and more.

Negative Ions
(Want More Science on Negative Ions and what they are ? Visit http://www.dynamind.com/whatareions.htm )
What’s a HEPA filter? What does it help with?
Here’s a video that explains it…
Here’s an interesting air purifier. It has 9-technologies including HEPA and UV but what is real interesting is the new Japanese pollen and allergen sensors which detect when there is a problem in the air.
by Don Baker Lewis
I know what you’re thinking: What’s he talking about? How does the seemingly harmless air inside my home or office lead to illness? I thought for a while before I used this title. After all it’s a pretty strong statement, and I don’t think of myself as an alarmist.
Take a look at what the World Health Organization found from their studies of human exposure to indoor air pollution: In the year 2000 more than 1.5 million deaths occurred largely because of indoor air pollution. That’s one death about every 20 seconds, worldwide. From indoor air pollution. Even if it’s only a fraction of that, it’s still shocking.