Since the outbreak of coronavirus, in short, known as COVID-19, people of all ages have become vulnerable to this infectious virus. To curb the transmission rate and keep oneself protected, World Health Organisation (WHO) has advised to wear a face mask.
In addition, people begin to buy masks that are available in the market. Among all the masks, disposable and surgical masks have gained popularity not just because of their price but also its functionalities.
However, both the mask comprises specific characteristics that distinguish one from the other. American Society for Testing and Materials, in short, known as ASTM has set the standard where the mask's level is determined on the basis of its materials and overall performance. Pondering all the aspects of ASTM standard, a disposable mask is considered the Level1 and Surgical mask as Level-2 face mask.
Then what is the difference between these Level-1 and Level-2?
To breakdown the criteria of standard levels, all the category masks are evaluated based on the four different components present in the mask. Those are
The fluid resistance of a mask gauged in the mmHg metrics, which is set by the ASTM. Simply, fluid resistance measures the ability of a mask's construction to minimize the fluid from penetrating through the fabric material and the potential coming into contact with the wearer. So this means the higher the fluid resistance present in the mask, the more protection you will get from the mask.
According to ASTM, the Level-1 mask has the 80 mmHg fluid resistance, which is quite lower than the upper level of standard masks. Level-2 mask, on the other hand, has up to 120 mmHg fluid resistance.
Bacterial Filtration Efficiency
BFE, formally known as Bacterial Filtration Efficiency, plays the most prominent role in creating an effective barrier to protecting the wearer. Basically, it represents the percentage of bacteria filtered out of pore size of 1-5 microns.
ASTM measured and revealed that Level-1 masks have ≥ 95% of the BFE capability, whereas Level-2 standard masks have up to ≥ 98%.
Particulate Filtration Efficiency
Particulate Filtration Efficiency, in short, known as PFE, represents the percentage of particles filtered out of pore size of 0.1-1.0 micros.
The standard mask material and overall performance parameter say that Level-1 masks have ≥ 95% of the PFE, and Level-2 masks carry ≥ 98% of the filtration capability.
Delta P, mm H20/cm2
Delta P, mm H 2 0/cm 2 remains all the Level-1 and Level-2 masks, and it represents the pressure drop across the mask or resistance to airflow in mm H 2 0/cm 2 .
In simple words, it determines the overall breathability of both level masks. ASTM shared that the Level-1 mask has <4.0 breathability, and the Level-2 mask has <5.0 breathability. Note that the higher the Delta P, the less breathability, but the filtration will be the best.
According to ASTM, both Level-1 and Level-2 have 'CLASS-1' flammability, which means measuring the flame spread of the mask material.
After the above discussion and fundamental understanding of both levels of mask materials, performance, and most importantly, the safety aspect, Leve-1 mask, a disposable mask, is the best option for you. Stay safe, Stay healthy!