Due to increased demand over the years, many inexpensive incense options have entered the market. Most of these lower-quality incenses are made of dyed sawdust and added chemical spices. Chemical spices contain mainly aldehydes, ketones and esters.

There is very little transparency when it comes to incense ingredients. Many of the larger brands that sell incense sticks for $2/pack are not all that specific about the ingredients they use.

Bamboo sticks are often soaked in adhesive materials before they are coated with an incense mixture. Often they use urea-formaldehyde resin adhesives, with formaldehyde as a main component. While burning, it releases into the air. Many studies have shown that formaldehyde is highly toxic and considered a carcinogenic and teratogenic substance. 

Other gas emissions found in common incense include, carbon monoxide, sulfur dioxide, nitrogen dioxide, nitrous oxide, musk ketones, musk xylenes, and musk ambrette, benzene, polycyclic aromatic hydrocarbons, diethyl phthalate (DEP), and more. Some of these are known toxins, pollutants, and carcinogens, and some these are major irritants, which are known to take a toll on the lungs, heart, and other organs.

Charcoal incense products are not really any better. They often use sodium nitrate, or saltpeter, which acts as an accelerant to keep the charcoal burning. If you are looking to burn charcoal briquettes or discs for loose resin, go for ones that do not have accelerants. Charcoal incense cones are usually dipped in fragrance oils, and do not say whether or not they contain sodium nitrate, so beware.

While inhaling smoke in general is not great for your health, there are ways to lower your exposure to harmful chemicals. First, it's probably not best to burn cheap incense. If you can afford it, natural incense is a much better option. Some brands say their incense is "natural", but that may not be completely true.

But, if you love Nag Champa, no one is going to stop you, just make sure you are opening your windows to limit your exposure during use.

Solace incense has no added chemicals, fragrances, adhesives, aldehydes or any of the above. We also do not use essential oils in our incense. Everything you see on the ingredients list is everything used to make our incense.

There are no "scents" just the plants themselves. Cones are bonded with laha powder, a fine wood powder from Nepal, and distilled water. But we still recommend opening a window to let some of the smoke out for good measure.

Reach out with any questions. We love to talk incense.

More Info/Sources:

VOCs and Particulate Pollution due to Incense Burning in Temples, China

Chemical composition and potential health risks of raw Arabian incense (Bakhour)

Higher cytotoxicity and genotoxicity of burning incense than cigarette

Incense smoke: clinical, structural and molecular effects on airway disease