Materials Required
- HEPA Filter: A standard HEPA filter rated to capture particles as small as 0.3 microns (e.g., True HEPA).
- Fan: A fan that fits the size of your HEPA filter and can provide sufficient airflow (e.g., box fan, computer fan, or exhaust fan).
- Enclosure: A sturdy housing to hold the components (e.g., a cardboard box, wood frame, or acrylic casing).
- Activated Carbon Filter (Optional): For removing odors and volatile organic compounds (VOCs).
- Power Supply: Compatible with your fan’s power needs (e.g., plug-in adapter or batteries).
- Adhesive/Sealant: Duct tape, glue, or silicone to ensure airtight seals.
- Tools: Utility knife, screwdriver, and measuring tape.
Step-by-Step Instructions
1. Design the Prototype
- Determine the airflow requirements for the size of the room. For example, aim for at least 4-6 air changes per hour (ACH) in a small room.
- Sketch a basic design where air flows through the HEPA filter, powered by the fan.
2. Build the Enclosure
- Choose a material for the housing, ensuring it is durable and easy to modify.
- Cut openings for the fan and filter. The filter should sit securely within the enclosure to avoid leaks.
- Design a way to access the filter for replacement (e.g., a removable panel or slot).
3. Mount the Fan
- Position the fan so it draws air through the filter. Depending on your design, the fan can pull air through or push air into the room.
- Secure the fan to the housing using screws, brackets, or adhesive. Ensure no air escapes around the fan’s edges.
4. Install the HEPA Filter
- Place the HEPA filter tightly in its designated slot or compartment.
- Seal all edges of the filter with adhesive or tape to prevent unfiltered air from bypassing the filter.
5. Optional: Add an Activated Carbon Layer
- If dealing with odors or VOCs, place an activated carbon filter in series with the HEPA filter.
- Ensure both filters are snugly fitted to maintain efficient airflow.
6. Test the Airflow
- Power on the fan and test the air purifier. Use a smoke test (incense or a smoke stick) to observe airflow patterns and ensure there are no leaks.
- If the airflow is weak, consider using a more powerful fan or optimizing the enclosure design.
Tips for Optimization
- Airtight Sealing: Use foam gaskets or rubber strips for better sealing between components.
- Noise Reduction: Add soundproofing material around the fan if noise is an issue.
- Efficiency: Avoid overly restrictive filters or complex airflow paths to maintain efficiency.
- Sensors: Incorporate air quality sensors to monitor performance and detect pollutants.
- Energy Consumption: Choose energy-efficient fans to minimize power usage.
Testing and Evaluation
- Measure particulate removal efficiency using a particle counter.
- Evaluate the CADR (Clean Air Delivery Rate) by testing the time required to clear smoke or dust in a closed room.
- Test for ease of filter replacement and maintenance.
Future Improvements
- Add a UV-C light for sterilization of microorganisms.
- Build a smart controller with IoT capabilities for remote operation and monitoring.
- Experiment with advanced filter media (e.g., electrostatic or nanofiber filters).

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