Merv Rating of Carbon Filters
The main use of the carbon filters is to remove odors from the air because the filters are made with carbon-impregnated media and not from electrostatically charged filter media. This means that Carbon filters do not have an official MERV rating. Instead, carbon air filters work on a molecular level to reduce unwanted odors in your home’s air. If odor control is the main priority then the Carbon filters are exactly the type of filter that should be used.
While the main purpose of carbon furnace filters is to remove odors, unofficially our carbon air filters are most similar to providing air filtration at a MERV 8 level. If the goal is to remove smaller particles from the air such as dust then check your HVAC system for its recommended MERV level of filters. A higher MERV rating will result in cleaner air, but it also will reduce the airflow through the system and could result in damage and costly repairs if manufacturer specifications are not followed.
Below, this table shows the adsorption of carbon air filters for selected materials and odors that may occur in a home or business. Adsorption is the process by which atoms, ions or molecules from a gas, liquid or dissolved solid adhere to the surface of an adsorbent, in this case activated carbon.
ACTIVATED CARBON ADSORBENCY OF MATERIALS & ODORS
| Acetaldehyde | 2 |
| Acetic Acid | 4 |
| Acetic Anhydride | 4 |
| Acetone | 4 |
| Acetylene | 1 |
| Acrolein | 3 |
| Acrylic Acid | 4 |
| Acrylonitrile | 4 |
| Adhesives | 4 |
| Air-wick | 4 |
| Alcoholic Beverages | 4 |
| Alines | 2 |
| Amonia | 2 |
| Amyl acetate | 4 |
| Amyl alcohol | 4 |
| Amyl ether | 4 |
| Animal odors | 3 |
| Anesthetics | 3 |
| Aniline | 4 |
| Antiseptics | 4 |
| Asphalt fumes | 4 |
| Automobile exhaust | 3 |
| Bathroom smells | 4 |
| Benzene | 4 |
| Bleaching solutions | 3 |
| Body odors | 4 |
| Borane | 3 |
| Bromine | 4 |
| Burned flesh | 4 |
| Burned food | 4 |
| Burning fats | 4 |
| Butadiene | 3 |
| Butane | 2 |
| Butanone | 4 |
| Butyl acetate | 4 |
| Butyl alcohol | 4 |
| Butyl cellosole | 4 |
| Butyl chloride | 4 |
| Butyl ether | 4 |
| Butylene | 2 |
| Butyne | 2 |
| Butyraidehyde | 3 |
| Butyric acid | 4 |
| Camphor | 4 |
| Cancer odor | 4 |
| Caprylic acid | 4 |
| Carbolic acid | 4 |
| Carbon disulfide | 4 |
| Carbon dioxide | 1 |
| Carbon monoxide | 1 |
| Carbon tetrachloride | 4 |
| Cellsolve | 4 |
| Celloslove acetate | 4 |
| Charred materials | 4 |
| Cheese | 4 |
| Chlorine | 3 |
| Chlorobenzene | 4 |
| Chlorobaudiene | 4 |
| Chloroform | 4 |
| Chloronitropropane | 4 |
| Chloropierin | 4 |
| Cigarette smoke odor | 4 |
| Citrus and other fruits | 4 |
| Cleaning compounds | 4 |
| Coal smoke odor | 3 |
| Coabustion odors | 3 |
| Cooking odors | 4 |
| Corrosive gases | 3 |
| Creosote | 4 |
| Cresol | 4 |
| Crotonaldehyde | 4 |
| Cyclohexane | 4 |
| Cyclohexanol | 4 |
| Cyclohexanone | 4 |
| Cyclohexene | 4 |
| Dead Animals | 4 |
| Decane | 4 |
| Decaying Substances | 4 |
| Deodorants | 4 |
| Detergents | 4 |
| Dibromoethane | 4 |
| Dichlorobenzene | 4 |
| Dichlorodifluoromethane | 4 |
| Dichloroethane | 4 |
| Dichloroethylene | 4 |
| Dichloroethyl ether | 4 |
| Dicholoromonofluoromatha | 3 |
| Dichchloronitroethane | 4 |
| Dichloropropane | 4 |
| Dichlorotetrafluoroethane | 4 |
| Diesel fumes | 4 |
| Diethylamine | 3 |
| Diethyl ketone | 4 |
| Dimethylanilline | 4 |
| Dimethyisulfate | 4 |
| Dioxane | 4 |
| Dipropyl ketone | 4 |
| Disinfectants | 4 |
| Embalming odors | 4 |
| Ethane | 1 |
| Ether | 3 |
| Ethyl acelate | 4 |
| Ethyl acrylate | 4 |
| Ethyl alcohol | 4 |
| Ethyl amine | 3 |
| Ethyl benzene | 4 |
| Ethyl bromine | 4 |
| Ethyl chloride | 3 |
| Ethyl ether | 3 |
| Ethyl formate | 3 |
| Ethyl mercaplan | 3 |
| Ethyl silicate | 4 |
| Ethylene | 1 |
| Ethylene chlorohydrin | 4 |
| Ethylene dichloride | 4 |
| Ethylene oxide | 3 |
| Essential oils | 4 |
| Eucalyptole | 4 |
| Exhaust fumes | 3 |
| Female odors | 4 |
| Fertilizer | 4 |
| Film processing odors | 3 |
| Fish odors | 4 |
| Floral scents | 4 |
| Flurotrichloromethane | 3 |
| Food aromas | 4 |
| Formaldehhyde | 2 |
| Foraic acid | 3 |
| Fuel gases | 2 |
| Fumes | 3 |
| Gangrene | 4 |
| Garlic | 4 |
| Gasoline | 4 |
| Heptane | 4 |
| Heptylene | 4 |
| Hexane | 3 |
| Hexylene | 3 |
| Hexyne | 3 |
| Hospital odors | 4 |
| Household smells | 4 |
| Hydrogen | 1 |
| Hydrogen bromide | 3 |
| Hydrogen chloride | 2 |
| Hydrogen cyanide | 3 |
| Hydrogen fluoride | 2 |
| Hydrogen iodide | 3 |
| Hydrogen selenide | 2 |
| Hydrogen sulfide | 3 |
| Incense | 4 |
| Indole | 4 |
| Inorganic chemicals | 3 |
| Incomplete combustion | 3 |
| Industrial wastes | 3 |
| Iodine | 4 |
| Idoform | 4 |
| Irritants | 4 |
| Isophorone | 4 |
| Isoprene | 4 |
| Isopropyl acetate | 4 |
| Isopropyl alcohol | 4 |
| Isopropyl ether | 4 |
| Kerosene | 4 |
| Kitchen odors | 4 |
| Lactic acid | 4 |
| Lingering odors | 4 |
| Liquid fuels | 4 |
| Liquor odors | 4 |
| Lubricating Oils and grease | 4 |
| Lysol | 4 |
| Masking agents | 4 |
| Medicinal odors | 4 |
| Melons | 4 |
| Menthol | 4 |
| Mercaptans | 4 |
| Mesityl oxide | 4 |
| Methane | 3 |
| Methyl acelate | 3 |
| Methyl acrylate | 4 |
| Methy alcohol | 3 |
| Methyl bromide | 3 |
| Methyl butyl ketone | 4 |
| Methyl cellosolve | 4 |
| Methyl cellosive acetate | 4 |
| Methylchloride | 3 |
| Methyl chloroform | 4 |
| Methyl ether | 3 |
| Methyl ethyl ketone | 4 |
| Methyl Forcate | 3 |
| Methly ether | 4 |
| Methyl aercaptan | 4 |
| Methylcyclohexane | 4 |
| Methylcyclohexanol | 4 |
| Methylcyclohexanone | 4 |
| Methylene chloride | 4 |
| Mildew | 3 |
| Mixed Odors | 4 |
| Mold | 3 |
| Monochlorobenzene | 4 |
| Monofluorotrichloromethane | 4 |
| Moth balls | 4 |
| Naptha (coal tar) | 4 |
| Maptha (petroleum) | 4 |
| Naphthalene | 4 |
| Nicotine | 4 |
| Nitric acid | 3 |
| Nitro benzenes | 4 |
| Nitroethane | 4 |
| Nitrogen dioxide | 2 |
| Nitroglycerine | 4 |
| Nitromethane | 4 |
| Nitropropane | 4 |
| Nittotoluene | 4 |
| Nonane | 4 |
| Noxious gases | 3 |
| Octalene | 4 |
| Octane | 4 |
| Odorants | 4 |
| Onions | 4 |
| Organic chemicals | 4 |
| Ozone | 4 |
| Packing house odors | 4 |
| Paint and redecorating odor | 4 |
| Palmitic acid | 4 |
| Paper deteriorations | 4 |
| Paradichlorobenzene | 4 |
| Paste and glue | 4 |
| Pentane | 3 |
| Pentanone | 4 |
| Pentylene | 3 |
| Pentyne | 3 |
| Perchloroethylene | 4 |
| Perfumes, cosmetics | 4 |
| Perspirations | 4 |
| Persistent odors | 4 |
| Pet odors | 4 |
| Phenol | 4 |
| Phosgene | 3 |
| Pitch | 4 |
| Plastics | 4 |
| Poison gases | 3 |
| Pollen | 3 |
| Popcorn and candy | 4 |
| Poultry odors | 4 |
| Propane | 2 |
| Propionaldehyde | 3 |
| Propionicc acid | 4 |
| Propyl acetate | 4 |
| Propyl alcohol | 4 |
| Propyl chloride | 4 |
| Propyl ether | 4 |
| Propyl mercaptan | 4 |
| Propylene | 2 |
| Propyne | 2 |
| Putreyfying substances | 3 |
| Putrescine | 4 |
| Pyridine | 4 |
| Radiation products | 2 |
| Radon | 3 |
| Rancid oils | 4 |
| Resins | 4 |
| Reodorants | 4 |
| Ripening fruits | 4 |
| Rubber | 4 |
| Sauerdraut | 4 |
| Sewer odors | 4 |
| Skatole | 4 |
| Slaughtering odors | 3 |
| Smog | 4 |
| Soaps | 4 |
| Smoke | 4 |
| Solvents | 3 |
| Sour milks | 4 |
| Spilled beverages | 4 |
| Spoiled food stuffs | 4 |
| Stale odors | 4 |
| Stoddard solvent | 4 |
| Stuffiness | 4 |
| Styrene monomer | 4 |
| Sulfur dioxide | 2 |
| Sulfur trioxide | 3 |
| Sulfuric acid | 4 |
| Tar | 4 |
| Tarnishing gases | 3 |
| Tetrachloroethylene | 4 |
| Theartrical makeup odor | 4 |
| Tobacco smoke odor | 4 |
| Toilet odors | 4 |
| Toluene | 4 |
| Toluidine | 4 |
| Trichloroethylene | 4 |
| Trichloroethane | 4 |
| Turpentine | 4 |
| Urea | 4 |
| Uric acid | 4 |
| Valeric acid | 4 |
| Valericaldehyde | 4 |
| Vinegar | 4 |
| Vinyl chloride | 3 |
| Volatile materials | 3 |
| Waste products | 4 |
| Wood alcohol | 3 |
| Xylene | 4 |
Some contaminants listed in the table use specific chemical compounds, some represent classes of components, and others are mixtures of variable composition. Activated charcoal's capacity for odors varies somewhat with the concentration of air, humidity, temperature, and with the actual velocity used through the filters. The numbers given represent typical or average conditions and might vary in specific instances. The values in the table have been assembled from many sources including laboratory tests and field experience. In cases where numerical values were not available, the author has listed his opinion of the probable capacity based on general experience. This table should be used as a general rule only. The capacity index has the following meaning:
| 4. | High capacity for all materials in this category. One pound takes up about 20% to 50% of it's own weight-average about 1/3 (33 1/3%). This category includes most of the odor causing substances. |
| 3. | Satisfactory capacity for all items in this category. These constitute good applications but the capacity is not as high as for category 4. Absorbs about 10% to 25% of it's weight-average about 16.7%. |
| 2. | Includes substances which are not highly absorbed but which might be taken up sufficiently to give good service under the particular conditions of operation. These require individual checking. |
| 1. | Absorption capacity is low for these materials. Activated charcoal cannot be satisfactorily used to remove them under ordinary circumstances. |
* Straight activated charcoal does not have much capacity for some reactive gases, such as ammonia, formaldehyde, etc. In some cases where the gas is chemically reactive, appropriate impregnated activated charcoal can be recommended. Those odorants marked above with an asterisk fall into this category.
