<div class="FTQUOTE"><begin quote><i>Originally posted by: <b>jman</b></i>
We looked into air purifiers when our children were born/younger. We learned that all "filters" are passive filtration systems, and require the problem to come to them. This does not work very efficently or effectively (in my opinion). While researching air purifiers we learned about a system that is an "active" purification system. </end quote></div>
Well, in one sense you're right. A filter is passive unless it is hooked up to something that is moving air. Simply using a carbon brick is the truest essence of a passive filter. A filter that isn't hooked up to something that moves air at a high velocity (measured in cubic feet per minute or cfm) is worthless.
You are incorrect to say that all "filters" are passive filtration systems. Pretty much every device described in this thread has been about an active system, so I think maybe you misunderstood.
John, I'd be curious to know what your research into filter systems uncovered. I'm afraid that you may not have a firm grasp on what they involve. My profession is in air quality studies, so if there's anything I can help clear up, please let me know. There are a lot of myths out there about cleaning the air in the home.
-LightNlife