The Ancient Romans + Greeks burned incense during ceremonies to purify their spaces and connect with the gods. Modern-day Buddhists still burn incense to purify the mind. And Taoists cleanse their surroundings to ward off evil. But does incense actually purify the air—as in removing contaminants, pollutants, and other impurities?
Incense doesn’t purify a home’s air. In fact, it introduces harmful pollutants like particulate matter (PM), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). While a 2007 study claims medicinal smoke can reduce a room’s bacteria by 94%, most research suggests otherwise.
Now, the answer to this question largely depends on how you define the term “purify” (i.e., literally or spiritually). Keep reading to hear both sides of the argument: why incense doesn’t really purify the air and why some still believe (or insist) it does.
Table of Contents
Why Incense Doesn’t Really “Purify” the Air
By “purify,” in this context, I mean removing contaminants, pollutants, or impurities. The result is air that’s cleaner and healthier to breathe.
Here’s why incense doesn’t purify the air and could actually worsen indoor air quality by creating indoor air pollution:
Burning Incense Releases Dangerous Chemicals
Regardless of its physical form (i.e., powders, cones, sticks), incense products are generally a mix of plant-based materials, including:
- Tree resins (the sticky substance that oozes out of trees—or sap)
- Herbs
- Flowers
- Essential oils
- Among others
Now, these components contain organic compounds that give incense distinct aromas and a smoky ambiance.
When burned, the organic compounds undergo a series of chemical reactions. The heat of the lit flame breaks these organic materials down, releasing VOCs and other gasses into the air through a process known as pyrolysis. Combustion further decomposes these compounds, which then react with the oxygen in the air to create other byproducts.
Rather than pulling impurities from the air, burning incense introduces contaminants, including:
Particulate Matter
Particulate matter (or PM) is a blend of extremely small solid and liquid particles in the air, often measuring just a few micrometers in diameter. For reference, a single micrometer equals 0.000039 inches—or roughly 1/70–1/50 the diameter of a single strand of hair.
PM can vary greatly in size, but incense typically releases a very fine PM measuring 2.5 micrometers (PM2.5). A recent 2021 study from Vietnam revealed that burning incense indoors can increase PM2.5 concentration by some 120%.
But it’s what these levels mean for your overall health that raises red flags. Breathing these particles in allows them to travel deep into your lungs; according to the CDC, they can even reach your bloodstream.
Short-term PM exposure from incense can lead to coughing, sneezing, throat irritation, and other “minor” side effects. Months or even years of PM exposure can cause long-term health issues like heart attacks, premature death, cancers, and asthma.
Volatile Organic Compounds (VOCs)
Burning incense also releases volatile organic compounds—VOCs—into the air. VOCs are chemicals that evaporate easily at room temperature, vaporizing into gasses. Now, exactly which VOCs your incense release depends on the ingredients, the type, and the combustion process.
Not all VOCs are necessarily “bad,” either, as you can also find VOCs in many essential oils, which are typically safe in moderation. But the American Lung Association links breathing in VOCs to side effects like trouble breathing and eye and nose irritation.
Yet, it’s the combination of potentially harmful VOCs in the incense that raises health concerns, including the following:
Polycyclic Aromatic Hydrocarbons (PAHs)
Polycyclic aromatic hydrocarbons (PAHs) are a type of chemical largely found in gasoline, crude oil, and coal. Outside of incense, PAHs can enter the air through vehicle exhaust, tobacco smoke, and forest fires.
As incense slowly burns, it may also undergo a process known as incomplete combustion if the burning conditions aren’t just right. Incomplete combustion releases more smoke into the air and—thus—more pollutants like PAHs. Instead of breaking down the organic compounds completely, the incense gives off byproducts like soot, ash, and VOCs.
PAHs can trigger mild side effects like eye irritation, diarrhea, and vomiting when breathed in on a short-term basis and in large quantities. However, inhaling PAHs long-term can increase your risk of developing certain cancers (like breast and lung cancer). There’s also a higher risk of lung and cardiovascular diseases and asthma.
It’s safe to say that releasing these chemicals and gasses into your home’s air supply does more harm than good. There’s also no built-in “filtration system” within incense. That allows these chemicals to enter the air in potentially large amounts freely.
The Airborne Particles Are Challenging To Remove
Combining incense with an air purifier sounds like a clever way to get the best of both worlds. Introduce a powerful yet pleasing aroma into the space (via incense). Then, filter the potentially harmful contaminants out of the air (with the purifier).
Air purifiers with HEPA filters can reasonably pull 99.97% of particles and contaminants from the air—even particles as tiny as 0.3 microns (or a PM of 0.3). Yet, purifiers can’t completely remove the fine particles in incense smoke.
In fact, a study from 2021 found that introducing an air purifier to the mix only reduced the PM2.5 concentration from incense burning by 43.48–83.98%. An air purifier can remove some particles from the air (HEPA filters) and adsorb odors and some VOCs (activated carbon filters).
But it’s likely not entirely.
Improved ventilation, surface cleaning, and time are the most effective ways to remove the dangerous chemicals and gasses from incense.
If you already own an air purifier, make sure you’re using a HEPA air filter in your device (link brings you to Amazon). Be sure to replace it with a fresh one roughly every six months.
It Does Little More Than “Mask” Odors
Traditional incense is fragrant and can fill a room with the overpowering aroma of patchouli, myrrh, or frankincense. But on top of adding more impurities to a home’s air, incense does very little—if anything—to get rid of the current pollutants.
The problem is that incense doesn’t actually eliminate (or completely remove) odors but rather masks them.
As the incense slowly burns, it releases a thin, oddly mysterious stream of smoke full of aromatic compounds. These compounds evaporate into the air and diffuse. They travel from an area of higher concentration—the few feet around the incense—to lower concentration—the furthest corners of the room.
Those relaxing and pleasant odor molecules mix with the air and any lingering odors. But because incense is naturally potent, the cinnamon or French vanilla aroma is far more noticeable than the underlying “bad” odor. Incense appears to “get rid of” the smell entirely by replacing it with its own uber-fragrant scent.
However, the aroma of the incense will eventually fade, and the foul odor will re-emerge with time. If the source of the original odor was, in fact, a pollutant or contaminant, incense masks it temporarily rather than actually removing it.
Why Some Believe Incense Is an Air “Purifier”
As I mentioned at the top, some view “purifying” in a more spiritual, religious, or ritualistic sense rather than a literal sense.
Here are just a few of the reasons some dub incense “air purifiers”:
Some Incense (Supposedly) Have Antimicrobial Properties
Those who support incense say that several studies prove it can kill bacteria in the air (antimicrobial properties).
The recent studies suggesting as much include:
- A 2007 study shows that “medicinal smoke” can kill some 94% of airborne bacteria within an hour.
- A 2011 study suggests that some incense is so skilled at killing bacteria that it could be a fumigation alternative for hospital wards and labs.
- Research from 2018 implies that burning frankincense and myrrh can lower bacteria by 68%.
- More research from 2019 reveals that burning incense can reduce the amount of bacteria in the mouth.
The issue is that no big-name organizations seemed to pick up the story. If something could really kill 94% of bacteria, you’d think it’d get national coverage.
It’s also worth mentioning that some of these studies were “in-vitro” (or conducted in petri-dish or test-tube). Also, while some oils and plants do have antimicrobial properties, very few (if any) recent studies suggest those traits remain when burned.
Centuries-Old Cultural + Religious Reasons
Incense may not literally purify the air. However, many cultures and religions burn incense as a meaningful symbol, to present an “offering” to the gods, or to “purify” a person or place of “bad air.”
Here are a few religions and cultures that do burn incense for purification purposes:
Hinduism
Burning incense is a very large part of Hinduism. The belief is that the aroma of incense “pleases” the deities, helping to create a divine atmosphere during worship.
Offering incense is a traditional way to show reverence and devotion. The smoke purifies the space and enhances the overall spiritual experience.
Buddhism
In Buddhism, incense is an “offering” to Buddhas, bodhisattvas, and ancestors to express gratitude and respect. The fragrance of incense supposedly has a calming effect on the mind and assists in meditation. It’s also a way to purify your intentions and create a serene ambiance for spiritual practices.
Catholicism
Catholicism’s use of incense is rooted in ancient traditions. Burned during Mass or processions as a symbol of adoration, the smoke represents prayers rising to heaven and purifies the space. The aroma of incense is more of a sensory aid to engage in a more profound spiritual experience.
Taoism
Incense plays a crucial role in Taoism’s rituals and ceremonies, too. When burning incense, the smoke “attracts positive energy” while repelling negative forces.
Taoists view incense as a way to communicate with the gods and spirits. Yet, it also purifies the environment, enhances spiritual connection, and invites blessings.
Shintoism
In Shintoism, one of the two major religions in Japan, burning incense is an offering to the kami (gods or spirits) and creates a “sacred space.”
Shintoists believe incense purifies the self and the environment. This allows for a closer connection with the divine. Burning incense before entering a shrine or joining rituals signify purification and respect.
Indigenous Cultures
In some indigenous cultures, burning incense (or smudge sticks) is a major part of spiritual practices and ceremonies. The smoke from herbs—such as sage, cedar, or palo santo—carries prayers and intentions, purifies the space. It also removes negative energies and is a way to connect with spirits and ancestors.
Traditional Chinese Culture
Incense has a rich history in traditional Chinese culture. In Chinese culture, burning incense is associated with gatherings, festivals, or ancestral worship. The incense cleanses the environment, brings good fortune, and pays respects to ancestors.
Final Thoughts
Ultimately, incense doesn’t purify a home’s air, as many believe. But it can provide a sense of “purity” or “cleansing” from a religious or spiritual perspective.
If your goal is to, in fact, purify your home’s air, you’re better off improving your home’s ventilation and introducing a HEPA air filter. You should also keep the joint clean and clear out air pollutants.
