ASTM International is an organization that sets standards for medical face masks, including surgical masks and procedure masks. The ASTM classifies masks into three levels: Level 1, Level 2, and Level 3. The classification is based on the mask's ability to filter out particles, as well as its breathability.

ASTM Level 1 masks are the lowest level of protection. They are designed for low-risk situations and are intended for use in environments where there is minimal exposure to fluids and/or sprays. These masks have a 95% filtration efficiency for particles that are at least 0.1 microns in size. They are also relatively breathable, making them comfortable to wear for extended periods of time.

ASTM Level 2 masks are designed for moderate-risk situations and are intended for use in environments where there is moderate exposure to fluids and/or sprays. These masks have a 98% filtration efficiency for particles that are at least 0.1 microns in size. They are also relatively breathable, but may be less comfortable to wear for extended periods of time compared to Level 1 masks.

ASTM Level 3 masks are the highest level of protection and are intended for use in environments where there is high exposure to fluids and/or sprays. These masks have a 98% filtration efficiency for particles that are at least 0.1 microns in size. They also have a higher resistance to fluid penetration, which makes them ideal for use in surgical settings. However, these masks may be less breathable and may not be as comfortable to wear for extended periods of time compared to Level 1 or Level 2 masks.

It's important to note that ASTM levels are not the same as N95 or KN95 ratings. ASTM levels are based on the mask's ability to filter out particles and its breathability, while N95 and KN95 ratings are based on the mask's ability to filter out at least 95% of airborne particles.

In conclusion, ASTM International classifies medical face masks into three levels: Level 1, Level 2, and Level 3. The level of protection is based on the mask's ability to filter out particles and its breathability. Level 1 masks are the lowest level of protection, while Level 3 masks are the highest level of protection. The level of mask required will depend on the type of environment and the level of exposure to fluids and/or sprays. It's important to choose the right level of mask for the specific task, and to follow the guidelines provided by the healthcare professionals and government.