Is burning incense sticks at home harmful to your lungs and cells?

What's actually in it

Burning incense produces a complex mix of fine and ultrafine particles, carbon monoxide, benzene, formaldehyde, and polycyclic aromatic hydrocarbons (PAHs). The visible smoke is just the beginning. The most dangerous particles are the ones too small to see, often smaller than 2.5 microns (PM2.5). These tiny particles can travel deep into your lungs and even enter your bloodstream.

A single incense stick burning in a closed room can push PM2.5 levels to several times higher than what the World Health Organization considers safe for outdoor air. And unlike outdoor pollution, indoor smoke lingers. It settles on furniture, walls, and bedding, creating ongoing exposure.

What the research says

A 2026 study in Chem Res Toxicol tested incense aerosols of different particle sizes on human cells. The researchers found that incense particles triggered reactive oxygen species (ROS) production, which caused mitochondrial dysfunction and programmed cell death across multiple human cell types.

In simple terms: incense smoke particles damage the tiny power plants inside your cells (mitochondria), generate harmful free radicals, and ultimately kill the cells. This happened in lung cells, skin cells, and other tissue types.

The smaller particles caused more damage than larger ones because they penetrate deeper into tissue. This is especially concerning for people who burn incense daily, as the repeated exposure gives cells less time to recover between sessions.

If you enjoy the ritual of incense, safer alternatives include beeswax candles (unscented), essential oil diffusers that use water mist, or simply opening a window to bring fresh air in. If you do burn incense occasionally, keep the room well ventilated and don't sit directly in the smoke stream.