In trying to find the best cabin air filter (CAF) to buy, I came across a veritable mountain of opinions, arguments, and “my filter can beat up your filter” rants on several forums. Wow, if you ever want to start WWIII just get into a discussion on tires, oil, or filters. I was able to find one source that rigorously and scientifically tested several CAFs by passing diesel exhaust through them and measuring what contaminants got past and the sensory effects on human test subjects. In a nut shell, the CAFs with activated charcoal were significantly better at reducing the odor and contaminants from diesel exhaust. Link to article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1757727/pdf/v056p00222.pdf Unfortunately, the filter companies understandably did not let their brands be known to the researchers. So all we can say is that filters w activated charcoal are much better than those without it, but not which one with charcoal is the best. If you don’t have allergies or don’t drive in cities with exhaust right in front of you, you could do without the charcoal but since I’ve found a very inexpensive source for them (below), I’m using them. Took out the Clarity’s CAF by pushing sides of glovebox inward and lowering. Then reach in and remove CAF housing cover by pressing in on the connectors on each end and pulling forward. The OEM filter is very nice w 30 pleats but has no activated charcoal. So it’s aftermarket with charcoal for me. Finding CAFs that fit the Clarity took some effort since once again the Clarity is too new to be on mfgs search engines. So I called my dealer’s parts dept (go to church w David there so I trust him) and found out that the Clarity CAF cross references with one that fits the 2018 Civic 4 door EX-T (or Ta/TL/TLa). Searching for that I found that the Fram Fresh Breeze CF11182 fits that. It has charcoal and baking soda. It’s $38 to $43 at auto parts stores but only $21 to $22 at Amazon and Walmart (WM temp out). Link to Amazon: https://www.amazon.com/gp/aw/d/B00EAOIRI4/ref=mp_s_a_1_1?ie=UTF8&qid=1526920307&sr=8-1&pi=AC_SX236_SY340_QL65&keywords=fram+cf11182&dpPl=1&dpID=51C0iXuNWrL&ref=plSrch Then I found on Amazon an EPAuto filter CP182 (cross references to the Fram CF11182) with charcoal for only $9. Same number of pleats as Fram (26ish) and w good reviews. Amazon Link: https://www.amazon.com/gp/aw/d/B074BHR574/ref=mp_s_a_1_2?ie=UTF8&qid=1526920307&sr=8-2&pi=AC_SX236_SY340_QL65&keywords=fram+cf11182&dpPl=1&dpID=514ZnP%2BNiNL&ref=plSrch So if you’re a namebrand kind of person order the Fram for $21,save a lot over the OEM and get the benefit of the charcoal. I (being cheap) ordered 3 of the EPAuto ones for $26.91 to get free shipping and at that price, I won’t feel bad about changing them often. Will post on them when they come in. And interestingly, after only 3 months and very little fan usage, I found a lot of large objects like bugs, seeds and grass on the filter. Just tapped those out. Filter still looked white with no dust accumulation. Will change out later w charcoal EPAuto filter.