Naturally your filters will last longer in a nice clean suburb as opposed to one located in the center of New York City. Is there separate media used for odor and gas removal. Indoor air contains in addition to dust particles often gaseous pollutants and odors. Since this pollution is in a gaseous state rather than a solid or liquid state, different filter technologies are needed to filter gases than particles. Clearly, more is better than less but here quality makes a significant difference to the adsorption rate .Carbon is often mixed in with zeolite, a cheaper fill.
Carbon comes in three kinds- dust, coconut shell or granulated.
The latter is the most expensive A. Granular activated carbon This substance is used in many larger air cleaners. While it may be effective for the removal of gases and odors that are drawn through the unit, it often significantly reduces the airflow of the air cleaner, which means that not enough air is being cleaned by the unit. Zeolite is a mineral. Since it is less expensive than activated carbon, many manufacturers like to mix it in with activated carbon to lower their production costs. Some manufacturers claim that zeolite is efficient for the control ammonia.