Since incense sticks are so small, you might not consider their environmental impact.
However, they’re not good for the environment as they are a source of air pollution.
They are also typically single-use items, so there is always a demand to create new incense sticks, requiring more energy and resources.
Here’s everything you need to know about incense and sustainability.
1. What Are Incense Sticks Made Of?
Incense sticks are wooden sticks coated in a powder to release a scent when burned.
You might also find incense sticks made from bamboo instead of wood.
The powder on the top of the stick contains wood, herbal compounds, fragrances, and adhesives.
The herbal and wooden powders can include:
- Chinese licorice
- Cinnamomum cassia (Chinese cinnamon)
- Nardostachys chinensis Bastal
- Rheum officinale Baill. (Chinese rhubarb)
- Radix Aucklandia
- Wild ginger
- Magnolia liliiflora
- Eugenia caryophyllata thumb
Many commercial incense sticks contain synthetic fragrances.
It’s hard to determine what’s in synthetic fragrances since it’s such a broad term, so it’s not easy to gauge their environmental impact.
Incense stick brands also use fragrances from plant and animal sources, such as the following:
- Lysimachia foenum-graecum
- Chinese juniper
- Taiwanese sweet gum
- Indian sandalwood
The adhesive powder is often made from the bark of Machilus nanmu, litsea glutinosa, or other trees.
However, Indian incense sticks are often bound with diethyl phthalate, which is released into the air, and may be toxic.
2. How Do Incense Sticks Affect the Environment?
Since most of the components of incense sticks are natural, renewable, and predominantly plant-based, you might think they don’t have much of an environmental impact.
However, renewable resources must still be treated with care.
For example, because it takes decades for trees to mature, wood should always be sourced responsibly to ensure forests can replenish themselves.
The biggest concern about incense sticks is the smoke they emit.
However, incense sticks seem to generate considerably more smoke, so there is more of an impact.
Burning incense sticks can emit particulate matter, carbon dioxide, nitrogen dioxide, and sulfur dioxide.
They can also emit benzene and toluene, as well as other volatile organic compounds (VOCs) like xylenes, polycyclic aromatic hydrocarbons, and aldehydes.
Carbon dioxide and sulfur dioxides are greenhouse gasses.
Although nitrogen dioxide is not a greenhouse gas, it does play a role in creating the greenhouse gas tropospheric ozone.
VOCs are potent sources of air pollution. Benzene plays a role in the formation of smog.
While frequent exposure to aldehydes may have mutagenic or carcinogenic effects, some people are more at risk due to genetics.
Polycyclic aromatic hydrocarbons can also act as carcinogens and are toxic.
Toluene is harmful to plants and marine life and long-term, low-level exposure can affect the kidneys.
Burning incense sticks can also release isoprene, which reacts with other compounds in the air.
For example, if isoprene reacts with nitrogen oxides, it can create ozone, but if it interacts with hydroxyl radicals, it can lengthen the time it takes for methane to break down.
This is concerning given that although methane breaks down in the atmosphere considerably quicker than carbon dioxide, it has the potential to trap more heat so it still contributes massively to the greenhouse effect.
Another impact is that incense sticks are typically single-use items and have a short lifespan.
They can typically burn for up to an hour and a half before the fragrance has run out.
After that, only the wooden or bamboo stick remains.
So, there is a regular demand for new incense sticks, as you can get through a packet pretty quickly.
Although wood and bamboo are biodegradable, incense sticks may not be biodegradable if they are coated in a synthetic varnish or paint.
3. Do Incense Sticks Cause Air Pollution?
Incense sticks can cause air pollution.
Research found that after burning incense, the amount of benzene emitted was much higher than the levels suggested by Hong Kong’s Indoor Air Quality Objectives for Office Buildings.
It was also found that the concentrations of polycyclic aromatic hydrocarbons were 27 times higher inside than outside when burning incense in a temple and outdoors.
These compounds were also found in dust after burning incense inside a Swiss church.
So, while burning one stick for a few minutes is not going to have a big impact, burning several incense sticks indoors with little ventilation drastically reduces air quality.
4. Are Incense Sticks Toxic?
Some of the compounds released from incense sticks may be toxic, but occasionally burning one incense stick in your home every now and then is unlikely to pose any serious issues.
Although research suggests that particulate matter may be linked to respiratory issues, there is nothing to suggest that this is solely from incense sticks.
With that said, burning incense does generate quite a lot of particulate matter: cigarettes burned approximately 10 mg/g, but incense generated more than 45 mg/g.
As mentioned earlier, diethyl phthalate and polycyclic aromatic hydrocarbons are toxic.
5. Are Incense Sticks Biodegradable?
While bamboo and wood are biodegradable, this is only the case if the handle of the stick is unvarnished.
It is not clear if the top part of the stick is biodegradable; although the fragrance and adhesives are typically plant-based, many incense brands still rely on synthetic materials.
If your incense sticks are not clearly labeled as biodegradable, it’s best to assume they’re not.
6. Are There Eco-Friendly Incense Sticks?
Some incense sticks may be more sustainable than others, but there do not appear to be any fully eco-friendly incense sticks available.
For example, bamboo incense sticks are arguably greener than wooden incense sticks because bamboo grows faster than wood, meaning it’s easier to replenish.
Research suggests that adding calcium carbonate to incense sticks can reduce the amount of particulate matter and polycyclic aromatic hydrocarbons (PAHs) released, which could make them safer.
Reed diffusers are likely safer than incense sticks as you do not burn them. Instead, they are sticks placed in fragrance oils or essential oil.
Similarly, you can also opt for wooden oil diffusers, which don’t cause any air pollution.
With that said, while essential oils are also often plant-based, they’re not a perfect solution either.
This is because studies show that essential oils can still negatively impact indoor air quality, which can have an impact on cognitive function – but they do seem to have fewer negative effects than burning incense sticks.