I have been in the HVAC Business for over 25 Years.  Air Filtration and Indoor Air Quality is my specialty and I am routinely called on to consult and design systems for prominent end users some of which include the Homeland Security, NEA and even Utility Companies.

Air Filtration is basically simple...the more efficient a filtration device is, the more your habitat or building is protected. However, Buyers always need "To Beware"or simply be educated. 

There are many products that fail in their "stated claims" (and hide the "downside" to their product) than those that ACTUALLY provide you with a Quality Product with NO HARMFUL SIDE EFFECTS! The most common harmful side effect in filtration is Ozone Generation.

To Review my Air Filter Selection Guide in full, please visit:

http://stores.ebay.com/The-HVAC-Store/Selecting-the-Correct-Filter.html 

If you ever wish to contact me, call Ed at 913.825.4999 or 913.522.8511.