Resources and Support for Multiple Chemical Sensitivities, Environmental Illness, and Chemical Injuries in Canada

HEPA Filtration


1 box-style fan
1 HEPA filter
aluminum foil tape

(Tip: if purchasing a new fan, try to get one with steel housing or grates as plastics emit VOCs. As well, wash all parts of the fan that are possible to wash safely with soapy water (using soap that you tolerate) or some water with baking soda. Doing so will help to remove traces of manufacturing oils.)

It is possible to make an inexpensive hepa filter using a only a box-style fan and a hepa filter. For this style of unit, it is important to ensure that the cord on the fan sits at the bottom or edge of the fan casing, rather than in the center so it won't interfere with the filter. It is also best if the fan and filter are close to the same size.

Simply tape the filter to the rear of the fan using tape to join the two together. I prefer to use aluminum foil tape as the adhesives on the tape are not able to off-gas through the foil, where with other types of tape, the tape material is often something I don't tolerate and the adhesives gas-off through it. With foil tape, the foil acts as a barrier to the adhesive and prevents that occurring.

HEPA and VOC Combined

If you react to the adhesives in HEPA filters, "sandwich" the Honeywell charcoal material between the fan and HEPA filter to help adsorb any offgassing. As the air is drawn through the HEPA filter, it will pass through the charcoal fabric and be adsorbed in it. Depending on the strength of the fan, you may be able to use two layers of the charcoal fabric, but be certain the fan doesn't overheat.

Note: Honeywell brand Activated Carbon Pre-filter No. 38002 (The front of the box reads "Universal Replacement Pre-Filter". The charcoal sheet measures approximately 16 inches by 48 inches when unfolded.)

Note re materials: The Honeywell carbon filter comes wrapped in cellophane with two pieces of Velcro-style tape which hold it together during shipping. The filter should be easily found at a home hardware store such as Rona or Home Depot or any store that sells Honeywell brand air cleaners. Home Depot carries it in my area for approximately $13.00.

CAUTION: Be sure to check the fan does not overheat. Please have someone knowledgeable (if you are not) double-check your work so that you do not create a fire hazard or otherwise do something dangerous.

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