Issue No. 2 | April 2020 | 12th Volume

BY: FRANK M. PARKER, III – CIH, CSP, PE, BCEE

Everywhere you look these days you see folks wearing disposable masks. They’re on TV, in the stores and on the street. Here’s an overview of respirators, their types, nomenclature and, most importantly, their limitations.

The ones most often seen are the “Disposables”. They are frequently described as a “paper” mask that fits over the nose and mouth. They are also commonly identified as N95 masks. The body of a disposable mask, the white material, is the filtration media. For the N95 at least 95% of particles greater than 0.3μ microns, or 300 nanometers, will be captured and removed from the air you breathe that has passed through the filtration media. Unfortunately, viruses are in the size range of 100 nanometers. Consequently, a single virus most likely won’t be stopped by a N95 mask. Fortunately, most viruses are contained in droplets from a cough or sneeze and which are much larger than 0.3μ. Also, the filter media on a NIOSH approved N95 masks is at least 95% efficient, some are more that 99% efficient. However, they were not designed to be used in environments containing acute
hazards where failure would result in putting the wearer in acute danger.

First, and foremost, please read the manufacturer’s instructions on the proper use and limitations of their mask. Knowing what the mask WON’T DO is critical! Read the instructions.

These disposable masks have several basic problems. First is obtaining and preserving a tight face seal throughout the time it is worn. Without a face seal the air simply bypasses the filter media and is inhaled unfiltered. We did a study of over 700 fit tests on a variety of these masks during the H1N1 outbreak. Untrained workers, who simply donned these masks, failed to obtain a face seal some half the time. Some 10% of the workers never obtained a satisfactory face seal with the masks we had available.

The second problem is durability. These disposable masks were not designed, nor marketed, for use over long periods of time. The thought being that there would be ample supply to replace many times a day if necessary. Wearing a disposable mask all day, and even longer, is very problematic. They are not that durable. Moisture buildup, especially those masks without exhalation valves, leads to structural failure and loss of face seal rather quickly. Also, any time they are touched or bumped the face seal is threatened.

Finally, like all personal protective equipment [PPE], the mask can become a source of contamination itself. Viruses can collect on the mask’s surface and be directly transmitted to the wearer, especially when being removed. It is important that the mask be the LAST piece of PPE removed and that the wearer take great caution not to touch the outside of the mask. Remove using the straps or inserting a finger inside the mask at the chin. Discard immediately. Reuse of a mask raises the possibility that the inside of the mask has been contaminated and will make the virus directly accessible to your respiratory system.

There are other disposable masks, in addition to the N95, to consider. These include the P95, R95, N100, P100 and the R100. The 100 series approaches 100% efficiency. The “P” notation indicates use for protection against oil & non–oil particles with time limitations specified by the manufacturer. The “R” notation indicates use for protection against oil and non–oil particles with time limitations specified by NIOSH.

For people with colds, or anyone coughing and/or sneezing, wearing a disposable mask helps protect those other folks in your immediate area. However, any mask or other barrier can be used for this purpose. Using an N, P or R designated mask should not be used unless no other class of mask is available.

If you have any questions or if we can be of any help during these trying times just give us a cal