Anti-pollution masks are no longer limited to workplace safety kit products. The COVID-19 pandemic has made these masks necessary as they help reduce exposure to pollutants and minimize health impacts. Globally, institutions have defined various standards so as to ensure that these anti-pollution masks adhering to them are actually effective when used in the right manner for preventing the spread of infection.
NIOSH (National Institute for Occupational Safety and Health) is the United States federal agency that is responsible for managing and maintaining face masks' standards. It comes under the Centre for Disease Control and Prevention (CDC) within the U.S. Department of Health and Human Services. NIOSH air filtration rating describes the device's ability to protect the wearer from dust and liquid droplets in the air.
Filter Classification - N, R and P Rating
N, R, and P are NIOSH certification categories that apply to negative pressure air-purifying respirators that protect against respiratory particulates. NIOSH has defined the three types of filter classification, namely N, P and R, which classify the masks as per the filter’s resistance when the masks are exposed to oil-based aerosols. This classification letter, when combined with the minimum filtration efficiency level, gives the rating of the face mask. The N, R and P categories indicate the mask’s resistance to oil degradation. The absence of oil particles in the environment allows the use of N-, R-, or P-series masks. The presence of oil particles requires the use of an R- or P-series filter.
Particulate matter or PM with a diameter over 0.3 microns or 0.0003 mm are effectively blocked by the N, R and P-type masks. This actually means that they are effective against PM10 and PM2.5 – a particulate matter of diameter less than 10 microns and 2.5 microns, respectively – except for very minute particulates.
N Type - Not Oil Resistant (only stops airborne particulate)
Rating N (refers to Not Oil Resistant) is for the mask type, which basically prevents spores, bacteria, and particulate matter from crossing the mask and is not oil-resistant. They do not resist airborne oil particles that often include harmful chemicals like toluene and benzene. N type masks are the ones that can be used continuously for relatively long durations before they have to be cleaned.
R Type - Oil Resistant (resists airborne particulate matter, also oil-based pollutants to some extent)
Rating R (refers to Resistant to oil) type masks go one step further and resist oil particles. The R-series of masks are oil resistant, but they are not oil proof like the P-series. For instance, R95 can stop 95% of particulate matter and some oil-based pollutants. These masks are only for a single shift or 8 hours of continuous or intermittent use and the re-use of R type masks beyond a single shift or 8 hours is not recommended.
P Type - Oil Proof (stops airborne particulate matter as well as oil-based pollutants)
Finally, P type masks are oil-proof, but the only drawback is that they get dirty over a shorter period, as compared to N type masks. Hence P type masks have to be cleaned more frequently and have shorter lifespans. For users who want total protection, they should buy the P type mask. The primary difference between P series and N series masks is that the P based masks can stop the oil-based pollutants the other cannot. Hence P series masks, even the P95 masks, are more expensive, are not readily available, and require replacement after forty hours of use. Hence these masks are recommended for industrial use and are not meant for everyday use.
N, R and P rating along with the minimum filtration efficiency level namely 95, 99, and 100, gives the final type of mask like N95, N99, P95 etc. The minimum filtration efficiency is defined as the percentage of blocking 0.3-micron particles. Out of the resultant nine combinations, N95 and N99 respirator types are the most commonly discussed one.
However, if you are unwell and notice any kind of respiratory health problems or suffer from a heart disease, it is advisable to consult a doctor before investing further in an anti-pollution mask or respirator. But when you are using the mask, just check if the mask fits you properly because if you do not use a mask correctly - it will fail to protect you against pollution and infections. Hence, learn how to correctly put the mask on and wear it correctly for longer periods. By taking some simple measures, not only can you stay safe but also save lives by protecting others from the COVID-19 virus.