This type of respirator is approved for protection against dust and mists. Older pesticide labels may refer to the particulate filter mask as a NIOSH TC-84A respirator.
NIOSH classifies particulate filters based on oil resistance:
- N, not resistant to oil;
- R, resistant to oil for up to 8 hours; and
- P, oil-proof.
And, efficiency based on how well it protects against particles at least 0.3 microns in diameter (1 micron = 1/25,000 of an inch):
- 95, 95 percent;
- 99, 99 percent; and
- 100, 99.97 percent
For example, an N95 particulate mask is not resistant to oil (N), and will filter 95 percent of particulates 0.3 microns or larger (95). In addition to N, R, and P, some filters may be rated HE for high efficiency (these are used with powered air-purifying respirators only). This is similar to the 100 efficiency rating. The 95 filters should be appropriate for most pesticides, as most pesticide spray particles are larger than 2 microns. Always refer to the pesticide label for specific requirements.
Several types of respirators that filter particulates are available:
- Particulate filtering facepiece respirators (masks) usually are made of a cloth-like filter material. An example is the two-strap particulate filter respirator. It can be adjusted for a better fit to protect against dust and other particulates. Two models of NIOSH-approved (TC-84A) particulate filter respirators are shown below. Both have a metal band at the nose area for adjustment. The mask on the left has straps that are not adjustable; its shape and construction may make it difficult to form the tight seal needed for protection. The mask on the right has adjustable straps and an exhalalation valve that helps minimize the buildup of heat and humidity within the mask (3M photo).
- Particulate filters also are available for half-mask and full-facepiece respirators. These respirators are meant to be reused many times, and have particulate filters that snap into place, are sometimes used alone, or are sometimes used with chemical cartridges. The full-facepiece respirator pictured below provides protection against dusts as well as eye protection. Keep in mind that a particulate filter does not provide protection against vapors.
While wearing the particulate filter respirator, if breathing becomes difficult or you taste or smell the substance, the filter is no longer effective. Typically, filters for reusable particulate filter masks are meant to be replaced when they have reached the service life listed by the manufacturer or when breathing becomes difficult-whichever comes first. Although the half-mask and full-facepiece masks are reusable, replace them if the mask loses its shape and you cannot adjust it to form a tight seal around your face.