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All About Respirators and Dust Masks
Keeping airborne dust and debris out of your lungs

The first are particulate contaminants. These are measured in microns with 1 micron equaling 1/25,400 of an inch...pretty small by anyone's standards. Particulates below 10 microns are the most likely to enter the respiratory system...and those below 5 microns are the most likely to reach the deep lungs, where they can do the most damage. In healthy lungs, 5 to 10 micron particles are usually removed from the upper respiratory system by a constant cleansing action. Smaller particulates are not.

It's also important to note that excessive exposure to even the larger-sized particulates can significantly reduce the efficiency of this cleansing action. Woodworkers should be most concerned by 1/2 to 10 micron particles that are most frequently filtered out by “fibrous” filters.

Secondly, vapor and mist particles (measuring five to 100 microns) that are created by fumes and the spraying of toxic finishes should also be a concern for the home woodworker. Organic vapors and sprays such as solvents, glues, thinners and finishes can create a serious hazard in the home shop. These are most often eliminated through the use of a chemical or charcoal-filled cartridge.

Respirator types and styles
Air-purifying dust masks are available as inexpensive throwaway types that are usually designed to capture only airborne dust particulates. There are also rubber or silicon type respirators with replaceable cartridges designed to capture various combinations of dust particles, vapors and mists.

Among these two types, there are three styles to choose from:

Quarter-face masks and respirators cover the nose and mouth while resting above the chin. Of these, you can select your choice of inexpensive fibrous or paper-like throwaways that typically cost $1 or $2 each...or rubber/silicon models that run $10 to $15. The latter of these use either one or two replaceable filters costing about $6 to $10 each. Most of these are designed ONLY for removing dust particles and not vapors or mists. Some throwaway models feature built-in exhalation vents to ease breathing and be “cooler” for the wearer.

Half-face respirators also cover the nose and mouth, but do so while resting under the chin. These are typically $25 to $50 rubber or silicon models...usually with two replaceable filter cartridges costing around $10 to $22 for a pair.

Most of these are designed primarily for removing vapors and mists...but will also remove airborne dust particles, providing a fibrous pre-filter is also used. These disposable pre-filters average under $5. The respirator carried in Shopsmith's catalog falls within this category.

Full-face respirators seal under the chin and around cheeks, temples and forehead, providing the maximum in respiratory as well as eye protection. Many of these are what OSHA classifies as being of the PAPR (Powered Air-Purifying Respirator) “atmosphere supplying” variety.

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