Definition: An N95 respirator equipped with a one-way exhalation valve designed to reduce breathing resistance and improve comfort while maintaining ≥95% filtration efficiency against non-oily particles (per NIOSH standards).

Key Features & Mechanism

1. Valve Functionality
   • Exhalation Phase: Valve opens to release warm, humid air, reducing heat buildup and moisture inside the mask.
   • Inhalation Phase: Valve closes automatically, ensuring filtered air intake through the mask material.
2. Filtration Performance
   • Filters ≥95% of airborne particles (e.g., dust, pollutants, viruses*) but does not filter exhaled breath.
   • Compliant with NIOSH (US), GB2626-2019 (China), or equivalent standards.

Advantages

• Enhanced Comfort: Ideal for prolonged use in high-exertion settings (e.g., construction, manufacturing).
• Reduced Respiratory Effort: Beneficial for individuals with asthma, COPD, or cardiovascular conditions.
• Reusable Options: Some valved N95 models feature replaceable filters, extending usability.

Limitations

• Unidirectional Protection: Protects the wearer but fails to block pathogen transmission from the wearer to others (e.g., COVID-19).
• Restricted Use in Healthcare: Banned in most hospitals and clinics (per WHO and CDC guidelines) due to infection control risks.

Recommended Applications

Critical Considerations

• Ethical Responsibility: Avoid using valved masks during outbreaks to prevent community spread.
• Pair with Alternatives: In high-risk areas, combine with a surgical mask over the valve or opt for valveless N95/KN95 masks.

Final Note: While valved N95s excel in comfort and occupational safety, their use must align with public health priorities. Always verify local regulations and outbreak advisories.