The Science Behind Diffusers and Plant Compounds

September 30th 2026

(plus the spa’s new aromatherapy system)

It’s no secret that you breath better with cleaner air, but we love scents too.

Since 5,000 BCE in fact, when Egyptians, Chinese, Greeks, and Romans burned incense to diffuse plant resins and oils in heated stones or clay vessels. In Egypt, the most famous example is kyphi – a complex aromatic blend recorded in inscriptions at Edfu and Philae. Kyphi contained ingredients like myrrh, frankincense, juniper berries, cinnamon, and various resins, combined with honey and wine. It was burned as incense, believed to have calming properties and to serve as an offering to the gods. In India, ayurvedic tradition in ancient texts mixed sandalwood, jasmine, rose, and dozens of other botanicals for aromatherapy as a tool for supporting mental balance and emotional well-being. In China, aromatic fumigation was used in traditional Chinese healing practice to purify spaces and support recovery using Agarwood (Chen Xiang), Sandalwood (Tan Xiang), Mugwort / Moxa (Ai Ye), Atractylodes (Cang Zhu), Chinese Patchouli (Huo Xiang), Angelica Dahurica (Bai Zhi), Warming Spices (Clove, Cinnamon, Star Anise), and Neroli / Citrus Blossom (Chu Luan).

The 1832 cholera epidemic was so devastating to France, it took 100,000 of it’s citizens and became the start of France’s hygiene obsession. Medical authorities relied on the miasma theory (believing disease spread through foul air from decaying matter) which has been supported from many civilizations via “aromatic fumigation” in the treatment areas. Wealthy citizens and doctors carried bags with rosemary, lavender, thyme, and sage to ward off foul air. Hospitals, homes and streets burned resinous woods, pitch, and herbs in public squares to create heavy smoke intended to “neutralize” the invisible, airborne cholera vectors. By 1937 the French chemist René-Maurice Gattefossé coined the word aromatherapy, which sounds to be fair, much better than “aromatic fumigation”.

In the mid-1850s, the first medical atomizers in France were developed to spray throat medicines and combat epidemics.

By the 1860’s France, aromatherapy and steam were deeply entwined in the beauty culture with the French referring the devices as pulvérisateurs or vaporisateurs. Barbers and hairdressers in Paris adopted them to spray scented oils and conditioning hair products onto clients.

Fast forward even more to the 1970’s and commercial aromatherapy devices were on the market worldwide.

How Plant Compounds Work in Diffusers

Essential oils are made of natural plant chemicals that are either steam distilled or cold pressed. These oils contain terpenes and aromatic molecules. When a diffuser breaks down the compounds into a fine vapor, you breathe them in. Those compounds interact with your olfactory nerves and send signals to your brain’s limbic system, which controls emotions and stress levels. These oils are usually intense concentrations.

Quality Considerations

Pure essential oils differ from synthetic “diffuser oils,” which may contain added chemicals or artificial fragrances. And this is where a lot of bad press comes into play. In the United States, there is no agency that over sees the quality of essential oil blends for diffusers. These things are not covered under the U.S. Food and Drug Administration (FDA) and even more concerning, labels that say “therapeutic grade” or “pure tested grade” are internal marketing terms created by companies not a government agency.

Compare this to the European Union which enforces strict, multi-layered chemical safety laws that hold manufacturers legally accountable for every ingredient. In the EU, essential oil blends meant for ambient scenting and diffusers must comply with a rigid combination of environmental, safety, and chemical regulations.

And this lack of oversight has led to complaints of health issues in the United States for diffuser oils and devices that have made people sick, caused adverse reactions and more. I blame companies for: Synthetic Additives: Many cheap blends contain phthalates, artificial fragrances, and chemical solvents that irritate the lungs. High Concentration: Unregulated labels rarely include safe diffusion guidelines, leading people to use toxic amounts. Pet and Child Toxicity: Common oils like tea tree, eucalyptus, and peppermint have unregulated labels that do not warm the products are highly toxic to dogs and cats, and can cause respiratory distress in infants.

The Science When Diffusers and Plant Compounds Are Used Correctly

Studies show that you can boost your natural immunity by inhaling plant oils called phytoncides which increases your body’s natural killer (NK) cells that fight viruses and cancer. These oils also lower levels of cortisol, the main hormone linked to worry and stress.

Clinical research indicates that inhaling aromas rich in geraniol (such as Palmarosa Pine) significantly lowers physiological stress markers. It has been shown to reduce diastolic blood pressure, stabilize the heart rate, and stimulate the parasympathetic nervous system to promote calm.

The Spa’s New Aromatherapy System

Our new system runs intermittently and automatically, on a schedule to start working at 10am and stop fully at 7pm only during the days we are open. It does not run continuously and we have adjusted the strength for the amount of square feet in our spa. This new feature is extremely helpful to our staff as we only have to fill the solution once each month.

We worked with a professional company to create a signature scent you can only find at the spa, using quality oils with no synthetic additives or chemical solvents.

We designed the blend to include:

Palmarosa Pine- is best known for its high monoterpenol content, particularly geraniol, which gives it a reputation for being restorative, antimicrobial, and supportive during periods of physical or emotional depletion.

Hemlock Pine

Pine Needles

Beta Pinene 26%
Alpha Pinene 13%
Delta 3 Carene 18%
Limonene 10%

Peruvian Cypress- is best known for it’s dominant monoterpene α-Pinene and δ-3-Carene which assist in respitory support. Cedrol also makes up part of it’s chemical composition and is a sesquiterpene alcohol known for grounding and sedative aromatic qualities.

Why so much pine? Alpha-pinene and 3-carene are major parts of pine oils. A study in scientific literature found that 3-carene can have anxiolytic (anxiety-reducing) and sleep-enhancing effects by interacting with specific receptors in the brain sleep-supporting agent via interaction with GABA receptors. Respiratory support- Pine oil is used as a natural decongestant and expectorant. Inhaling the vapor helps clear mucus and ease breathing during mild respiratory discomfort

Himalayan Cedarwood – acts as a mild expectorant, clearing airways, loosening and clear mucus from the respiratory tract. This oil has a dry, balsamic, and slightly spicy scent profile and is traditionally used to clear mental clutter.

b-Himachalene: b-Himachalene and Himachal are both sesquiterpenes, which show insecticidal properties. Scientists believe it is likely that Himachal has antispasmodic properties. Studies on animals indicate the effectiveness of this component in treating spasms, including its ability to reduce blood pressure and increase blood flow to the muscles. β-Himachalene is one of the significant components to make sure of the Cedarwood Essential Oil benefits.
Caryophyllene: This component is the same one that contributes to the scent of black pepper. Interestingly enough, caryophyllene is also a non-psychoactive cannabinoid. Studies looking at its anti-inflammatory effects believe it may be very effective in fighting conditions such as diabetes.
Linalool: Linalool is a terpene known for its fragrant, floral aroma. It is also a naturally occurring pesticide, common in the control of pests such as ticks, fleas, and mosquitoes. It is listed by the United States Environmental Protection Agency as a biopesticide, under the classification of “practically non-toxic” for acute inhalation, and “slightly toxic” for oral or dermal use.
Limonene: Limonene is most common in citrus fruits, though also present in some other Essential Oils such as Cedarwood. Studies indicate this component is an effective antioxidant and anti-inflammatory agent.

Balsam Fir- Native to North America, particularly Canada and the northeastern United States, balsam fir has long been used by Indigenous cultures for its healing and soothing effects. Just like Himalayan Cedarwood, Balsam Fir assists in respiratory support, and contains Beta-Pinene (anti-inflammatory and bronchodilating effects, reduces inflammation), Alpha-Pinene (compound has antioxidant and antimicrobial properties) and Bornyl Acetate (works with the brain’s limbic system promotes relaxation).

B-pinene: Very common in many essential oils, b-pinene is in the monoterpene group. It has a smell reminiscent of pine and contributes to balsam fir oil’s invigorating aroma. Though more research is needed, studies indicate b-pinene to be an antimicrobial, anti-inflammatory, and anticancer agent. It is one of the most significant components that contributes a lot to balsam fir essential oil benefits.
Delta-3-Carene: d-3-carene is a monoterpene, and one of the main reasons for the sharp, resinous smell of fir trees. Studies show d-3-carene can potentially offer benefits in terms of bone health, as well as being an effective antifungal agent.
Bornyl Acetate: This component of balsam fir oil is an acetate ester. It is a common additive in food and flavorings, as well as having use as an anti-odor agent.
a-Pinene: Another monoterpene, a-Pinene is also common in the essential oils of many plants. This component shows indications of being an effective antimicrobial agent, leading scientists to make the recommendation for further research on its use in antimicrobial therapy. Similar to b-Pinene, it also shows signs of being an effective agent in many other types of treatments. Many balsam fir essential oil benefits are dependent on this component.
Limonene: Limonene also falls under the monoterpene classification. It gets its name from the French word “limon”, as it is most prevalent in the rinds of citrus fruits. In balsam fir oil it contributes to the resinous pine-like aroma, and studies indicate it has many potential health benefits.
B-Phellandrene: b-Phellandrene occurs naturally in Canadian firs. It is a common additive to fragrances, due to its aroma, which is mild and smells of mint and sweet citrus.
Camphene: Camphene is also common in many fragrances, as well as being a useful flavoring agent.
Terpineol: Terpineol is a terpenoid that has been modified by an alcohol. It has a pleasant aroma, with a scent similar to that of lilacs. Studies done on terpineols indicate their potential use as anti-hypertensive agents, in addition to their potential anticancer properties.

Juniper Berry alpha-pinene, helps calm the nervous system

Beta-pinene: Research shows b-pinene holds promise as an antibacterial and antimicrobial agent, particularly against the common Candida Albicans. It is also a common additive in many products such as dairy and baked goods. Beta-pinene is one of the most important components taking part in Juniper Berry Essential Oil benefits.
Beta-myrcene: Studies show beta-myrcene to be a significantly effective anti-inflammatory. It also shows indications of working as a mild sedative, which may explain the anecdotal claims that Juniper Berry Essential Oil can help to induce sleep.
Alpha-pinene: a-Pinene is a known antimicrobial agent. A study found a-Pinene to be an effective inhibitor of gram-positive bacteria. Scientists recommend further research on a-pinene to gauge its use in antimicrobial therapy.
Limonene: Limonene is present in many essential oils, including Juniper Berries. Research indicates it has antioxidant and anti-inflammatory properties. However, until more about limonene is known, its main use will continue to be as a key ingredient in drinks, food, cleaning products, and even insect repellents.
Sabinene: A potentially effective anti –inflammatory, making sure of the Juniper Berry Essential Oil benefits.
Terpinen-4-ol: Terpinen-4-ol shows significant promise in terms of cancer treatment. Research indicates it is capable of causing cancer cell death both alone and in conjunction with other treatments.
Gamma-Terpinene: This component is also found in Eucalyptus Essential Oils, and studies show it to have anti-inflammatory properties.
Delta-3-carene: Research on delta-3-carene indicates it may have antifungal properties.
a-Terpinene: Indications show a-Terpinene may possess anti-inflammatory tendencies.