European standard EN 149 defines the following classes of “filtering half masks” (also called “filtering face pieces”), that is respirators that are entirely or substantially constructed of filtering material:

Both European standard EN 143 and EN 149 test filter penetration with both dry sodium chloride and paraffin oil aerosols, after storing the filters at 70 °C and -30 °C for 24 h each. The standards also include tests on mechanical strength, breathing resistance and clogging. EN 149 also tests the inward leakage between the mask and face (ten human subjects perform five exercises each and for eight of these individuals the average measured inward leakage listed above must not be exceeded).

FFP1, FFP2 and FFP3 are different classes of respirator; they offer different levels of wearer protection. Simply put, the higher the protection factor the better the reduction to the airborne contaminant. FFP1, FFP2 and FFP3 respirators can reduce the amount of dust you breathe by factors of 4, 10 and 20 respectively.

It is important to consider the type and level of contaminants to which workers will be exposed. Once you have properly evaluated the airborne hazards in the workplace, you can begin to choose dust masks based on their FFP rating. The best dust mask for your workplace will be one that meets the appropriate FFP rating, and is comfortable and convenient for your workers.

Finding a suitable respirator is not just a matter of choosing a model you like or by the cost of it. You may need to try different makes or sizes to find one that fits without leaking around the seal and letting dust in. A respirator that depends on face fit is ineffectual if you have a beard or thick beard stubble. The only way you can know if the seal is good enough is by having a proper respirator fit test.

You should discard disposable respirators at the end of the shift or sooner if they are heavily contaminated. Never hang up a respirator in a dusty place for use later on.