Protective masks, such as surgical masks and N95 respirators, are designed to filter out harmful particles and prevent the spread of infectious diseases. Surgical masks primarily protect others from the wearer's respiratory emissions, while N95 masks provide a higher level of protection by filtering out at least 95% of airborne particles, including viruses and bacteria. They are commonly used in healthcare settings, during pandemics, and in environments with poor air quality. Proper fit and usage are crucial for their effectiveness.