1. Clearly define the filtering purpose
Particulate matter pollution (such as dust, pollen, PM2.5): Choose a mechanical filter (such as HEPA) specifically designed for particulate matter.
Gaseous pollutants (such as formaldehyde, odors): Chemical filters containing activated carbon should be selected.
Microorganisms (such as bacteria and viruses): require antibacterial coatings or high-efficiency HEPA filters (H13 and above).
Industrial environments (such as factories and laboratories) require professional dust and chemical corrosion resistant filters.
2. Understand filter types and efficiency standards
Common types
Primary filter (G1-G4)：Filter large particles ≥ 5 μ m such as dust and hair.
Purpose: Pre filtering, protecting the backend high-efficiency filter.
Medium efficiency filter (M5-M6)：Filter 1-5 μ m particles such as pollen and fungal spores.
Usage: Commercial buildings, household fresh air systems.
High efficiency filter (H10-H14)：HEPA standard (H13 filters 99.97% of 0.3 μ m particles).
Usage: Hospital, laboratory, dust-free workshop.
Activated carbon filter：Adsorption of formaldehyde VOCs, Odor, but needs to be replaced regularly.
Electrostatic/Electronic Filters：By adsorbing particles with charges, it can be cleaned, but it may generate ozone.
International standard reference
ISO 16890 (for particulate matter, classified by PM1/PM2.5/PM10)
EN 1822 (HEPA/ULPA standard)
MERV rating (US standard, MERV 13-16 equivalent to HEPA)
3. Match usage scenarios
·household
Ordinary dust removal: MERV 8-12 (medium efficiency).
Allergy or asthma patients: HEPA (H13)+activated carbon.
Newly renovated house: HEPA+high iodine value activated carbon (adsorbing formaldehyde).
·Office/Commercial
Central air conditioning: Medium efficiency (MERV 11-13)+regular replacement.
·Hospital/Laboratory
HEPA (H13-H14)+antibacterial treatment, must comply with medical certification.
·industry
High temperature resistant and corrosion-resistant materials, such as fiberglass HEPA.
4. Consider device compatibility
Size: Measure the length, width, and thickness of the original filter of the measuring equipment to ensure compatibility.
Wind resistance: The high-efficiency filter has a large wind resistance, and it is necessary to check whether the fan can withstand it (to avoid reducing the air volume).
Installation method: The type of frame (such as bag, plate, folding) should match the equipment.
5. Evaluate maintenance costs
Replacement frequency: Initial effect every 1-3 months, HEPA every 6-12 months (depending on pollution level).
Cost: HEPA has a high unit price but is long-lasting, while initial efficiency is cheap but requires frequent replacement.
Washable type: The electrostatic filter can be reused, but the cleaning effect will be reduced.
6. Other precautions
Noise: High wind resistance filters may increase equipment noise.
Energy consumption: HEPA may increase the power consumption of air conditioning/fresh air systems.
Certification: Choose products with authoritative certifications (such as AHAM, CE, GB/T 18801-2015).
Ozone risk: Avoid purchasing inferior electrostatic filters (ozone concentration ≤0.05ppm)