According to the DDC, many Buddhists engage in religious rites during Buddhist holidays, and as such, the department cautions those who suffer from respiratory diseases, such as asthma, to avoid inhaling large amounts of smoke from joss sticks and other forms of incense. Inhalation of incense smoke may trigger symptoms. Breathing in incense smoke also leads to increased risk of cancer, as the aromatic substance contains three carcinogens: benzene, butadiene, and benzo(a)pyrene. These are released from the burning of glue and scented substances.
The lighting of one joss stick releases 325 grams of carbon dioxide and 7 grams of methane, which is equivalent to the release of 23 times the amount of carbon dioxide. These can all contribute to the formation of cancers such as leukemia, lung cancer, stomach cancer, etc. To reduce the amount of smoke released from a joss stick, the lit joss stick should first be dipped in water or sand before being set out.