Chemical cartridges and canisters (gas masks) for air purifying respirators use sorbents to remove contaminant-specific gases and vapors. Used by themselves, they provide no protection from pesticide particulates; including liquid droplets from sprays, smoke, fogs, or dusts. The type of chemical cartridge or canister that must be used is specified on the pesticide label.
The most typical chemical cartridge or canister specified by the label for pesticide use is an OV (organic vapor-removing) cartridge or canister. They contain activated carbon that adsorbs organic vapor gas or vapor molecules from the air being drawn in through the container. Always use the type of purifying element required by the pesticide label.
Types of commercially-available chemical cartridges include: organic vapors, formaldehyde, ammonia, mercury vapor, phosphine, and acid gases. Both chemical cartridge and high-efficiency particulate filter purifying elements are required by NIOSH to be labeled, as well as color-coded. For example, organic vapor-removing (OV) elements are coded black while P-100 series filters are color-coded magenta (see figure to right). HE particulate filters for powered air-purifying respirators (PAPRs) are also color-coded magenta.
Chemical purifying elements are also available for “multi-gas/vapor” removal. If a pesticide label specifies OV cartridges, a multi-gas/vapor element that also includes OV may also be used.
Source: Respiratory Protection for Occupational Users of Pesticides. Patricia D. Hastings, Coordinator, Rutgers Pesticide Safety Education Program.