A Good Surgical Mask obviously refers to one which can provide a high level of protection, is safe to wear, and allow comfortable easy breathing.
Here are the specifications to look out for and what they mean
BFE>95%
BFE refers to Bacterial Filtration Efficiency. A good 3Ply Surgical Mask will have a filter in the middle layer which largely determines the mask's effectiveness to filter out the dangerous particle or bacteria. A mask with B.F.E > 95% means at least 95% of the bacteria can be blocked by the mask filter material. The higher the BFE%, the more bacteria the mask can filter.
Recommended: BFE>95% (TYPE I) OR BFE > 98% (TYPE II)
PFE>95%
PFE refers to Particle Filtration Efficiency.
The higher the %, the better the wearer is protected from airborne particles, dust, and debris.
Recommended: PFE>95% OR PFE > 98%
EN14683 and/or ASTM F2100
Masks may have EN14683 European standards or ASTM F21000 US standards, meaning they passed quality, hygiene, and safety standards for medical use. For peace of mind, look for products that comply with EN14683 or ASTM F2100 standards.
Recommended: EN14683 or ASTM F2100 standards.
Delta -P Or Breathability
Delta-P (Breathability) Determines the resistance of the surgical facemask to the air flowing through the mask. A lower Delta-P translates to increased breathability and comfort.
Recommended: Delta P <40 Pa/cm²
CREDIBILITY
Ensure lab tests & regulatory certificates are from recognized or established approval bodies. Anyone can claim to have high-quality products but not all can be proven. Ask for Lab test reports & keep a lookout for labs that are internationally renowned, such as Nelson Labs. A Nelson Labs report looks like this:
CE & FDA are the most commonly recognized regulatory bodies.
Ask for Certificates to show proof of compliance with the standards.
Check on Seller's company to ensure it is legitimate. Eg. Exists prior to the COVID-19 period, valid website, live company registration, etc. Buying from an established medical company will likely give you better assurance on quality and safety.
To order Medical Grade Masks, visit: www.theairstation.com/personal-protection-equipment
For protection higher than surgical masks, see Respirators such as N95 and KN95 or Smart Masks which creates a facial seal.