Can incense smoke contain harmful pollutants? When incense is burned inside, the smoke created during this process can be a major source of indoor pollutants as it produces harmful gas and particulate matter (Cheng, Bechtold & Hung, 1995). In fact, many types of incense smoke have been found to contain carcinogens similar to those found in cigarette smoke (Friborg et al., 2008). The exact type of pollutants released into the air depends on the chemicals present in the incense being burned. However, a study that tested 23 different types of incense found that the concentrations of carbon monoxide (CO), nitric oxide (NO) and sulfur dioxide (SO2) gases found in incense smoke may be high enough to adversely affect your health (Jetter, et. al, 2002). That same study found that incense smoke emits high quantities of fine particulate matter that could cause the air inside your home to exceed the US EPA’s National Ambient Air Quality Standards (NAAQS). These standards were created by the EPA as a part of the Clean Air Act to protect against air pollutants deemed harmful to public health and to the environment. Because incense is usually burned in enclosed spaces with little ventilation, the particulate matter may accumulate in your home over time. If you regularly burn incense, you may be exposed to more harmful indoor air pollutants than you think.