The capacity index chart lists substances by both chemical and common name. It is a general list of the most common compounds found in the workplace. The efficiency and capacity of activated carbon to adsorb these substances varies with the concentration in the air, relative humidity and temperature. The capacity index numbers are representative under average conditions and may vary under local conditions.


All substances are rated on a scale from 1 to 4

4) HIGH ADSORPTION CAPACITY: Substances are adsorbed very efficiently. One pound of activated carbon adsorbs about 20% to 50% of its own weight – average about 1/3 (33-1/3%). This category includes most of the odor causing substances.

3) SATISFACTORY ADSORPTION CAPACITY: Substances are adsorbed well, but not as efficiently as substances rated 4. One pound of activated carbon adsorbs about 10 to 25% of its weight – average about 1/6 (16.7%).

2) MODERATE ADSORPTION CAPACITY: Substances are not highly absorbed but might be adsorbed sufficiently to give acceptable results under the particular operating conditions. These require individual checking.

1) POOR ADSORPTION CAPACITY: Substances that are not adsorbed by activated carbon fall into this category.

Note: Substances marked with *** are not adequately adsorbed by standard activated carbon. It is necessary to use treated (KMN) carbon to increase the adsorption efficiency.

CARBON CAPACITY INDEX (See Activated Carbon Capacity Chart)



Important Note:

This chart lists the relative effectiveness of activated carbon on various materials. The listing does not imply that the construction materials for carbon filters are impervious to all of the compounds shown.

The life expectancy of any purification/ filtration system is dependent on the concentration of the contaminants to which the system is exposed. Obviously, the consumption rate or life of the media will be shorter as the concentration of the gaseous contaminant increases. Also, be aware that in most real world cases there is no air stream with just one contaminant, but it almost always is accompanied by other gases. This must always be taken into consideration.

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