Purification Principles
Air purifiers utilize various purification technologies, including:
- Filtration
- Adsorption
- Electrostatic precipitation
- Photocatalysis
- Chemical catalysis
- Negative ion generation
- Composite methods
These methods can effectively remove one or more types of pollutants, such as particulate matter (PM), gaseous pollutants, and microorganisms, from the air.
2. Key Selection Metrics
2.1 Clean Air Delivery Rate (CADR)
- Definition: Measures the purifier’s pollutant removal efficiency. Higher CADR = better performance.
- Types:
- Particulate CADR (PM-CADR) – For dust, pollen, smoke, etc.
- Formaldehyde CADR (CH₂O-CADR) – For volatile organic compounds (VOCs).
2.2 Cumulative Purification Capacity (CCM)
- Definition: Evaluates the longevity of filters by measuring total pollutant removal capacity.
- Rating Systems:
- Particulate CCM: P1 (lowest) to P4 (highest).
- Formaldehyde CCM: F1 (lowest) to F4 (highest).
- Higher ratings indicate longer filter life.
2.3 Recommended Room Size
- Calculation: Based on CADR, following Chinese standards:
- S: Room area (m²).
- Q: Particulate CADR (m³/h).
- Note: This is a theoretical reference; actual usage may vary.
2.4 Priority Metrics
- CADR & CCM are the core indicators for evaluating purifier performance.
- Room size is secondary and should be used as a general guideline.
3. Selection Principles
- For PM + VOCs: Choose a purifier with dual filtration (e.g., HEPA + activated carbon).
- Performance Balance: Prioritize models with:
- High CADR & CCM
- Low noise (<40 dB for bedrooms)
- Energy-efficient (check energy rating)
- Quiet Operation: Essential for bedrooms or nighttime use.
- Sensitive Groups: Infants or respiratory patients should use ozone-free purifiers (physical filtration only).
- Room Size Matching: Select a CADR-appropriate model with moderate headroom (avoid oversized units).
