Wildfire Smoke? Smells? Virus? Clean Your Air!

by Beetlesmart

7.3K9644

Intro: Wildfire Smoke? Smells? Virus? Clean Your Air!

Got smoke smell from wildfires in your apartment? Want cleaner air in your classroom? Did you burn popcorn in the office microwave? Like to cook fish but hate the smell? Want to reduce dust, allergens, or viruses in the air where you live? Here's a cheap and easy way to help clean the air where you live or work. You can pick the level of filtration depending on your needs and its a super simple project. This project is perfect for teachers trying to stay healthy in their classrooms. If you know a teacher please consider making one a donating it.

STEP 1: Gather Your Materials

We will be building a simple Air Cleaner that will reduce smoke, soot, pollen, dust, bacteria, and viruses from the air in a room. You can select a filter to match your cleaning goal, whether it is a less expensive filter for dust, pollen, and mold or a slightly more expensive filter that also captures viruses, bacteria, soot and smoke. The cleaner will not remove all the particles in your room but it will help reduce them. I used mine for 3 hours and there was a noticeable reduction in smoke smell and irritation in my room, a major relief. Here is what you need to build your own simple Air Cleaner.

1. A simple box fan. I bought a 20 inch box fan from Target for under $20. Or click the link to order one on Amazon: https://amzn.to/3WJidE6

2. A 20" x 20" air filter. Each filter is rated by the particle size that it can filter. The one I'm using is a high performance air filter, at a rating of 1900 it will filter particles sized between 0.3 microns and 1 micron. This size range includes 99% of particles you breathe in. This filter will capture dust, pollen, smoke, bacteria, viruses and more. I bought it at Target for just under $20. Don't know which filter you need? Look for the symbols on the packaging to see what kind of particles each filter captures. Order them on Amazon: https://amzn.to/3IRm8cj

3. Duct tape, a classic. Order here on Amazon: https://amzn.to/3qoRn87

4. A pair of shears or strong scissors.

STEP 2: Understanding How the Air Cleaner Works Safely

Our objective is to fasten the air filter to the back of the fan so that air is pulled through the filter, expelling cleaned air into the room. You might consider just taping the full filter to the back of the fan and calling it a day. Here is why you shouldn't do that. The cord and control switch to turn the fan on/off and adjust its speed are usually located on the back of a box fan (see picture). Taping over this would block your ability to turn the fan off and on, or even plug in the power cord. Also, importantly, covering the air flow to the fan's motor could cause it to overheat, ruining the motor or even creating a fire hazard. To be safe, I've used a temperature gun to check the surface motor temperature after running the fan for 3 hours continuously in a cooled room. The outer motor temperature is 74 degrees, we will use this to compare the temperature on our finished project.

To keep the motor safe, we will be creating a path for air to reach and cool the motor. This will slightly reduce the amount of air passing through the filter, but it is a good trade off for safety. Now let's get started.

STEP 3: Fitting Our Filter

If you hold the filter to the back of the fan, you'll notice it is a good match. The only part of the filter we will trim is the center. The corners of the filter are also sticking out past the curved corners of the fan but that is okay, we will seal that.

Start by using a piece of paper to trace the outline of the motor/switch/plug plate on the back of the fan. Mine is round with a small bump at the top (see picture).Cut out the pattern and then draw an inner line and cut it again. You'll see why we do that in the next steps.

Now take the pattern and center it on the filter. You need the pattern to be exactly centered just like the fan motor, so measure the center of the plate on the fan and then transfer the measurement to the filter. Use a sharpie to mark the exact center of the filter and place the pattern centered on top of your mark.

STEP 4: Cutting the Filter

Now that we have our pattern placed, trace around it with a sharpie. Remove the pattern. We will now cut out the wire and the filter material. First use your shears or heavy duty scissors to snip the wire mesh on the top of the filter. The material is glued to the wire frame so you will have to gently peal it off as you remove the material to avoid tearing the filter. When this has been removed, use scissors to cut the filter material one pleat at a time, slow and steady. when you've cut the material pull it out carefully. Now flip the filter over and snip the wire mesh on the bottom of the filter. We now have a complete hole through the filter. You'll notice that the hole slightly overlaps the edges of the motor plate on the back off the fan. This is why we cut the pattern a second time, to make the filter hole smaller and create an overlap. The overlap will help seal the airflow around the motor plate, forcing more air into the filter and through the fan.

We still have raw edges on our filter and possibly sharp pieces of wire mesh. Cover the edges of the hole with duct tape. This will help seal the edges and cover the sharp edges of wire mesh. Cut pieces to wrap around front to back until the entire edge is covered. This will also prevent small pieces of the frayed edges of material from blowing through the fan.

STEP 5: Attaching the Filter to the Fan

Now we are ready to attach the filter to the back of the fan. Place the filter against the back of the fan. Be sure to follow the arrow on the filter so that the air is flowing in the correct direction (in from the back of the fan and out the front of the fan). Plug on the power cord to be sure you have clearance before you attach the filter in place. Now use duct tape to seal the edges of the filter to the back of the fan. The corners will require a few short strips of tape to create an airtight seal around the edges. Do not tape the center of the filter to the back of the motor plate. The suction created when the fan is turned on will pull the filter securely against the back of the fan.

As a final safety test, I ran the Air Cleaner continuously for three hours checking the temperature periodically. The temperature ran slightly higher occasionally reaching a still safe 76 degrees.

You are now ready to use your new Air Cleaner. Each filter lasts up to 3 months and can easily be removed and replaced as necessary. You can use different filters as your air conditions change, pollen/mold filters for allergy season, smoke/soot filters for wildfires, bacteria/virus filters for flu season. Cleaner air is only a quick project away, so try it out. Enjoy!

STEP 6: One Last Safety Message for Everyone Near the Wildfires

This filter can significantly reduce the smell of smoke in your home. However, don't let your guard down when monitoring wildfires that are close to your home. Please stay aware and stay safe during fire season. I'm wishing you good health and good luck.

36 Comments

DGretired 3 years ago

I made the 'hurry-up' version, by just taping a filter to the fan box to limit the spread of dust during a renovation while we lived in the space under renovation. The results weren't perfect but helped considerably. Thanks for mentioning ventilating the fan motor.

DennisSweitzer 3 years ago

That's impressive. I've seen the box fans filters with a 4inch thick filter as well, which will have a similar effect (as there is 4 times the surface area for the air to flow through), but also a similar price as 4 - 1 inch filters (presumably for the same reason -- 4x the filter material).

Beetlesmart 3 years ago

I really like this idea, I just have one concern, the same one mentioned in the article. With less drag on the fan the airflow becomes significantly stronger. Any droplets in the air could be circulated instead of being allowed to settle. There is a fine balance between getting enough airflow to do a good job filtering and getting too much airflow which increases the virus circulation. The article you linked mentions that they will be doing professional testing on the airflow. Its definitely one to watch, I know we all want the optimal balance to keep everyone as safe as we can. Thanks for linking it and your comments.

DennisSweitzer 3 years ago

COVID-19: Since high filtration HEPA filters can remove viruses & bacteria from the air, one might consider them for some protection against COVID-19. This article has many details:
https://tinyurl.com/FAQ-aerosols
"FAQs on Protecting Yourself from COVID-19 Aerosol Transmission" (it's very long, with lots of links to other resources. The section on filters starts at p51).
At least a MERV 13 (or MPR1900) is recommended for filtering out viruses.

There's been quite a debate about whether COVID-19 is transmitted by droplets (small particles which mostly drop out the of air within about 6 ft) or aerosols (smaller particles which float through the air and circulate for a long time), and the answer is almost certainly 'yes (both)' (viruses ride in expired particles of a range of sizes, and if the circumstances are right, larger droplets evaporate into smaller aerosols which can circulate quite easily).

It's recommended to pay attention to the 3 V's:
Venue (indoors or outdoors? Crowded or not?)
Ventilation (the better the airflow & more frequent the air changes, the fewer viruses).
Vocalization (the deeper you breath & louder you talk, the more viruses you'll emit--such as singing).


Beetlesmart 3 years ago

Great information, thanks for posting.

sheba92766 3 years ago

I have severe fragrance & chemical allergies/sensitivities, so I use an Oransi air purifier indoors that runs all the time. However, this would help in the event of smoke or someone comes in wearing perfume or sprays something before I can get them out of my house.

DennisSweitzer 3 years ago

You can get 20x20 furnace filters with activated charcoal to better remove odors (and they seem highly rated).

Beetlesmart 3 years ago

I hope it helps you, I can only imagine being constantly assailed by strong scents, ugh that’s rough.

lorenkinzel 3 years ago

This also works well to get rid of the plague of sheetrock dust while remodeling.

budc11 3 years ago

Used this for 29 years, never cut a hole for the fan. remember the fan is designed to work at hight temperatures than you are using. you may want to find one of the filters with activated charcole for smell

mOnsteviOus 3 years ago

I saw a version of this in a news story that also showed how effectively it worked. Within an hour it had cleaned a majority of the particles from the air in the room. I can't remember what tool they used to measure the particles but they had a nice graph showing their initial measurements and how it changed over the first few hours. The box fan they used didn't have a plug sticking out from the back and the power controls were on the top edge, so they didn't bother cutting a hole in the filter. They also didn't bother covering the corners/edges where the filter didn't completely cover the whole fan. The majority of the fan was covered and it was still extremely effective. I think they only used two strips of scotch tape to hold the filter in place. It looked so amateur I thought it was ridiculous but then they showed the results and I was dumbfounded. Your version likely works more effectively, further reducing the amount of time it takes to clean the air. Thumbs up to this great idea. Thanks for sharing this so more people can try it. So simple and inexpensive!

Beetlesmart 3 years ago

Thanks! It’s great to hear that this method is so measurably effective. All I’ve used for comparison is my/my friends’ improved breathing/reduced irritation. Scientific objective measurement is better though.

spark master 3 years ago

I have told this to so many people it is crazy, BUT you dear fellow made the thing availablebe through instructaible.

You get my vote, heck, I will add if you get a more open filter and run it all day it cuts down on dust in the rooms, it does cost you for electric, but it is good for those with no time to dust.

This concept of more open screen is even better with a mesh FOR REDUCING FLYING INSECTS.

We put fans out, out side in sitting areas, around outdoor animal sites (barns, styes) you can capture and kill gnats/mosquito's/HORSE FLIES, things that take a chunks outta your sweet tasty butt!

You can add OVI traps and wasp baits for more control, w/o pesticides. Ovi traps should be used in large numbers and if you can get neighbors to do same, you can control skeeters in a large area, over time. Then night of the party, just add the fans

Kudos Kudos Kudos!

sheba92766 3 years ago

So you use one of the cheaper, open-weave filters to catch/kill mosquitos & other pests? Do you attach it to the back as well?

Beetlesmart 3 years ago

Those are such great ideas! Also, if you want to use it outside, grind up some marigolds and rub it on the filter. The oil from the flower is a natural mosquito repellent. It makes a better party for sure. If you make one enter it in the REMIX contest, your ideas would really work (not sure about the date on that contest).

patrick94gsr 3 years ago

Note that running the fan in a home furnace will accomplish the same task. The filter for the furnace is on the "return" side, or the air being pulled from the room(s) into the furnace. So running the furnace in fan-only mode is basically the same as this, but it will filter the air for the entire home. But it will do the same if it's running in heating or air conditioning mode, as well.

A good use for this device would be somewhere that does not have a central heat/A-C system. Somewhere like a shop, garage or shed could benefit from having a filtered fan like this running, while it's being occupied.

Beetlesmart 3 years ago

That's a really good reminder. I'm using both at the moment, my home system needs some help so its a good little booster for me.
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