What do procedure/surgical masks primarily protect against?

Procedure or surgical masks primarily serve to protect against infections during surgeries. They are designed to act as a barrier that helps prevent pathogens from being transmitted from healthcare workers to patients, as well as to shield workers from droplets that may be expelled by patients. The use of these masks is critical in maintaining a sterile environment during procedures, minimizing the risk of surgical site infections.

While surgical masks can also reduce the likelihood of respiratory droplets from healthcare workers reaching the patient, their primary and most recognized purpose is infection control during surgical procedures. In the context of the other choices, while they may provide some level of droplet protection, they are not specifically designed to address exposure to substances like formaldehyde or to directly protect against healthcare workers' coughs outside of the surgical setting.