Biofiltration system: A system in which a moist living microbial substrate, such as a deep bed of inoculated mulch and bark at a waste water treatment facility, breaks down odors to chemical components before microbes feed on those compounds.

Carbon filtration system: A system in which an activated carbon substrate removes odors by collecting odor molecules onto the carbon (adsorption). These systems typically are found at exhaust points.

Deodorizer: General term for a product/agent that covers up or removes an unpleasant odor.

Fogging system: A system in which a liquid has been converted to a super fine misted particle (fog). Fog droplets trap dust and other particles. Odor neutralizing agents can be added to the air to mix with the droplets. Fog is visible and tends to travel along in local airstreams with minimal fallout on the ground.

Misting system: A system in which a liquid has been converted to a droplet. Visible droplets attract particles in the air (similar to a fogging system), and tend to fall out of the airstream close to their source.

Odor Masking Agent: A compound that covers up an unpleasant smell without changing the chemical structure of the malodor. An odor masking agent acts like a perfume.

Odor neutralizer: A compound that physically alters the chemical state of a malodor upon contact. Both malodors and odor neutralizers are typically not detectable after the chemical reaction when properly dosed.

Ozone generator system: A system that produces ozone (O3), which destroys some odorous molecules upon contact. Ozone can be lethal to humans and destructive to rubber at certain doses in an unventilated area.

Vapor Phase System: A system in which liquid has been converted to its gas state. Odor neutralizers in gas form are injected, and because of the molecules’ lighter weight and size, travel with the vapor through the air. Vapor (invisible) tends to travel in local airstreams without falling to the ground.

Volatile Organic Compound (VOC): Material derived from a natural source that a constituent part “boils” off at room temperature; can be naturally occurring, such as a plant-emitted scent, or manmade, like a combustion engine’s exhaust fumes. Not all VOCs are harmful.