The regular use of incense and candles indoors poses a health risk due to the emission of air pollutants.

noli's read

Dr. Jimmy Mohamed highlights the release of fine particles and volatile organic compounds (VOCs) during the combustion of these items. Research indeed confirms that burning incense and certain candles emits substances such as benzene, formaldehyde, and ultrafine particles (sources: ANSES studies and various environmental analyses, observational type/laboratory measurements). It holds true that the accumulation of these pollutants in poorly ventilated spaces degrades indoor air quality and can irritate the respiratory tract, particularly in sensitive individuals. The potentially exaggerated aspect lies in the term “danger,” which may suggest an immediate and serious risk, whereas it is primarily a question of concentration, frequency of use, and air renewal. It has not been proven that occasional use in a ventilated room presents a significant clinical risk for a healthy person. In summary, the risk is real for air quality, but it is manageable through good ventilation habits.

the sources

No named source held this one up — that absence is part of the verdict.