A HEPA filter captures a multitude of different particles including Pollen, dust, dirt, moisture, bacteria, viruses, and any other particles down to 0.3 microns in size. While carbon filters trap and smells and foul odors as well as stop large particles that would normally gum up your HEPA filter. This lengthens the lifespan of your HEPA filters. In order to have the most efficient air purification system, you need both a pre-filter and HEPA filter. In addition, you let all the large particles gum up your HEPA filter causing it to need to be changed more often, costing you more money in the long run. Breathe Naturally HEPA and Carbon filters are designed with you in mind to deliver a premium quality filter for the lowest price possible. Breathe Naturally HEPA filters are rated MERV 17, the same level used in clean rooms, hospitals, and airports/airplanes all around the world. Our Carbon Filters are made out of extra-thick carbon material that is made in the USA. It is specially cut to fit your exact filter or can be bought in bulk to cut down yourself. Carbon filters should be changed every 4-6 weeks with normal use and every 2-4 weeks with heavy use. Those with pets, high trafficked areas, live in a high pollution area, smoke, or live in close proximity to smokers, or those who need/want the best quality of air possible, should change their filters more often. The same goes for HEPA filters. Normal use needs changing every 4-6 months and heavy use every 3-4 months. You can dispose of the dirty filters in the garbage like normal.