Review on VEVA HEPA and Carbon Filter Replacement Kit - 2 Pack HEPA Air Filters & 6 Carbon Pre-Filters - Fits Air Purifier Series AC5000, AC5250PT, AC5300B, AC5350W, AC5350B, CDAP5500B & AP2800CA by Jason Ortiz

I thought all basic HEPA filters and activated carbon pre-filters were the same. I was wrong! I swapped out the original manufacturer filters for these and was extremely dissatisfied. These filters give off a chemical smell that takes my breath away, like an asthma attack. I'm more sensitive than most, but not so sensitive that I don't get around people who wear perfume. The cost of these filters is the only reason I gave them no stars. I suspect it would be possible to use a HEPA filter, but use the original manufacturer's pre-filter. I'm pretty sure the "charcoal pre-filter" is actually not just charcoal. I suspect there is some kind of coating to hide the fact that the filter is less dense than it should be.