Essential oils can be used to kill bacteria, mold, and odors caused by those microbes and they can break down synthetic fragrance.
When companies claim that their essential oils “purify the air”, they do this only in very specific ways and under specific circumstances.
They are (from what I have seen) referring to oils that break down bacteria or mold.
I also found in my personal experiment that citrus oils, which are high in d-limonene, can be used to break down synthetic scents like plug-in fragrance left on walls.
However, fogging essential oils leads to worsened air quality since it leads to high VOCs and PM2.5 pollution.
So let’s take a look at which oils to use and how to use them effectively.
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Oils That Can Clean the Air
1. Deodorizing Oil
Black Cumin Seed Oil prepared from the seeds of Nigella sativa L exhibited strong deodorizing activity against methyl mercaptan, which is a main factor in oral malodor (source).
2. Anti-Bacterial Oils
Fir oils, cinnamon, rosemary, tea tree, and copaiba are some of the oils that are anti-bacterial.
For a complete list of sources, see this article.
3. Antifungal Oils
Lemon, cinnamon, rosemary, and clove are a few of the anti-fungal oils.
For a complete list of sources, see this article.
4. Oils to Break Down Chemicals and Synthetic Fragrance
Oils high in d-limonene do a very good job at breaking down hydrocarbons, tar and asphaltic residues, some petroleum products, and some synthetic fragrance like plug-in odor on drywall and other materials.
Essential Oil Brands for Cleaning the Air
For Bacterial Odors:
Deodorizing by Plant Therapy – Palmarosa, Lemon, Patchouli, Coriander, Grapefruit Pink, Cypress, Bergamot, Tea Tree.
Purify by doTerra – Lemon Peel, Siberian Fir Needle, Citronella Grass, Lime Peel, Tea Tree Leaf, Cilantro Herb.
For Mold:
Germ Fighter by Plant Therapy – Cinnamon Cassia, Lemon, Eucalyptus, Clove, Rosemary.
On Guard by doTerra – Wild Orange Peel, Clove Bud, Cinnamon Leaf, Cinnamon Bark, Eucalyptus Leaf, and Rosemary Leaf/Flower.
Thieves Oil by Young Living – Clove bud oil, Lemon peel oil, Cinnamon bark oil, Eucalyptus leaf oil, Rosemary leaf oil.
For Methyl Mercaptan:
Black Cumin Seed Oil from Living Libations (which is made from the seeds of Nigella sativa).
To Break Down Plug-in Odor:
A citrus oil high in d-limonene.
I used organic grapefruit oil from Plant Therapy. You could also use orange oil or lemon oil.
Employing Essential Oils to Clean the Air
Diffusing/nebulizing essential oils is the best way to deploy them to kill bacteria or mold spores.
I would do this when people and pets are out of the room because diffusing creates high levels of VOCs and PM2.5 particulates (more on that in the section below).
To break down artificial fragrance, like plug-in odor, you can mix citrus oil into a dish soap and leave that on the surface as explained below.
I didn’t try diffusing citrus oils, but that could help break down plug-in odor if you can’t put a layer of soap and oil on the item.
Fogging to Kill Bacteria and Deodorize
If you want to kill bacterial odors in a room, diffuse or nebulize the essential oils on a timer of 1 to 2 hours (in most cases) while you are out of the room.
You can certainly do longer if the odor persists.
If you have indoor humidity that is on the higher side, don’t use a diffuser, instead use a waterless nebulizer.
This waterless nebulizer has a 1, 2 and 3 hour timer, and this waterless nebulizer can run on a 1, 2 or 3 hour timer.
Humidity could add to the source of bacteria, depending on what the cause is, so adding water may worsen things.
If you have low humidity you could use a diffuser with a timer (that uses some water), that one has a 1-hour minimum.
Cleaning to Break Down Synthetic Fragrance
Use 4 drops of grapefruit oil in a tablespoon of dish soap and leave it on the painted drywall or finished flooring that has the plug-in odor (or perhaps other synthetic fragrance) for an hour.
Then wash off with water.
If the fragranced item can’t be washed like this, you can try nebulizing using the instructions above for bacterial odors, except I would move the nebulizer around the room to hit more surfaces.
I did not try this myself.
Fogging to Kill Mold Spores
Dr. Edward R. Close, PhD in Environmental Engineering, diffused Thieves Oil blend (a blend of Clove (Syzygium aromaticum) bud oil, Lemon (Citrus limon) peel oil, Cinnamon (Cinnamomum verum) bark oil, Eucalyptus (Eucalyptus radiata) leaf oil, and Rosemary (Rosmarinus officinalis) leaf oil) in the Aroma-Ace Atomizing Diffuser in homes for a 24-hour period.
(You could also use the mix by Plant Therapy, which is made with the same oils but is less expensive).
Dr. Close and his wife, Jacquelyn Close, discovered that diffusing essential oils with a waterless cold air nebulizer was the best solution to address mold spores in buildings.
The results of their case studies showed a huge reduction in mold spores and it had a residual effect (i.e. the spores did not come back quickly).
Their research showed that the essential oils “digest” the mold spores that they come in contact with and don’t leave dead mold spores behind.
NOTE! If you have mold growing in walls, this does not address that underlying problem and the mycotoxins and mold VOCs being produced. Putting a bandaid on the situation could cause a false sense of security.
They recommend that you place one diffuser in each room (one for every 1000 sq ft) and diffuse continuously for a minimum of 24 hours.
How long you have to diffuse (24-48 hours or longer) is determined by air sampling or tape-lift sampling.
Use a glass plate under the diffuser to protect surfaces from the oil.
This book by Dr. Close and his wife goes into more detail.
If you prefer to watch a seminar about Dr. Close’s methods, this masterclass will be helpful. He is talking with mold-preventative architect Cheryl Ciecko. The other classes in the series will also be helpful in making sure you properly identify the source of the mold and safely clean mold (as you could do a lot of harm cleaning it yourself). Don’t just put a bandaid over it!
Essential Oils Increase VOCs
Essential oils increase VOCs and PM2.5 particulates when fogging.
For that reason, I recommend being out of the room while fogging or diffusing because you are temporarily increasing the problem of poor air quality.
Increase of Primary VOCs
Diffusing essential oils increases VOCs.
In one study each essential oil emitted between 20-140 VOCs.
The most prevalent VOCs were: alpha-pinene, Limonene, Acetone, Linalool, alpha-phellandrene, beta-myrcene, Camphene, Ethanol, beta-pinene, 3-carene, Eucalyptol, Acetaldehyde, Beta-phellandrene, Gamma-terpinene, M-cymene, beta-trans-ocimene, Methanol, and Terpinolene.
Amongst the most concerning are Acetaldehyde, Acetone, and Methanol (methyl alcohol) which are regulated by OSHA for occupational exposures.
The main constituents of turpentine/pine oil are also concerning (even if pine oil is not used): α-pinene, β-pinene, Camphene, and Limonene.
We know turpentine is toxic to inhale and other coniferous tree oils used in deodorizing oil blends have a similar composition.
These three studies have found that diffused essential oils such as lemon, lavender, eucalyptus, and tea tree, were found to release terpenes, Toluene, and Benzene, among other VOCs, into the air.
Toluene and Benzene are also regulated by OSHA and both are Prop 65 Chemicals.
Benzene because it can cause cancer and birth defects or other reproductive harm, and Toluene because it can cause birth defects or other reproductive harm, according to the State of California.
Increase Formaldehyde Production
There is also a secondary reaction that can lead to substantial levels of formaldehyde.
Natural compounds in essential oils, such as terpenes, contribute to the formation of formaldehyde and nano-sized secondary organic aerosols (SOAs) through the reaction of terpenes with the natural indoor background level of ozone (source).
Essential Oils Increase Particulates
Essential oils diffusers also increase PM2.5.
They can take the levels from 7 to almost 1400 PM2.5 within seconds, as shown here!!
And here are two more formal studies showing the PM2.5 results.
PM2.5 is the main particulate air pollutant whose diameter is less than 2.5 microns.
Various respiratory diseases are associated with PM2.5 inhalation.
Jeffrey Siegel, Ph.D., Professor of Civil Engineering and indoor air quality expert, doesn’t recommend essential oil diffusers because of the particulates and VOCs they produce.
This is the main reason I personally do not use essential oil diffusers/nebulizers if I’m in the room.
Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.
Join the top Substack on healing from MCS and mold!
Laoise
Hi Corinne,
After fogging the house for 24 hours how long should you wait before going back into the house?
Thank you so much.
Corinne Segura, Building Biologist
I’m sure dr close has the recommendations on that, I know it’s not long though. unless you are sensitive to essential oils then you should let it go down for a few days.
Laoise
Hi Corinne,
I really appreciate your getting back to me. Thank you so much!! One last question if you don’t mind.
We just painted the room after doing remediation work and burning the oils.
I would like to burn the oils once more just to be sure as much spores as possible are digested after all the work that was done.
Is it safe to burn the oils with the vocs of the fresh paint bring in the room.
Thank you so much.
Laoise
That should be ‘with the bics from fresh paint being in the room’
Laoise
Vocs