The use of masks includes:

1. Medical purposes:
    - Surgical masks to prevent germ transmission
    - Respirators to filter airborne pathogens
    - Oxygen therapy masks
2. Protection:
    - Dust masks for construction or cleaning
    - Gas masks for chemical or biological threats
    - Particle masks for air pollution
3. Cultural or spiritual significance:
    - Ceremonial masks in various cultures
    - Ritual masks for spiritual or religious practices
4. Entertainment and performance:
    - Theatrical masks for acting or drama
    - Costume masks for Halloween or cosplay
5. Fashion and beauty:
    - Decorative masks for masquerade balls or parties
    - Face masks for skincare or beauty treatments
6. Sports and recreation:
    - Paintball masks for protection
    - Ski masks for warmth and protection
7. Military and law enforcement:
    - Gas masks for chemical warfare
    - Ballistic masks for protection