Fragrance, volatile organic compound, and particulate matter emissions from incense burning: Observations and risk assessments for household rooms and temples in Japan

Abstract

In Japanese society, incense is often burned indoors for its fragrance and as a part of Buddhist rituals. However, fragrances and volatile organic compounds (VOCs) emitted by incense burning can adversely affect human health. Japanese products are not required to disclose fragrances included; therefore, the number of these compounds to which users are exposed is unclear. This study aimed to evaluate the human health risks associated with incense burning in household rooms and temples. Chamber tests demonstrated that incense sticks used in the home contained higher concentrations of fragrance than those used in temples. Consequently, the level of fragrance contained in smoke from incense used in the home (1,100–9,200 μg stick⁻¹) was greater than that from temple incense smoke (15–84 μg stick⁻¹). The concentration of VOCs derived from the pyrolysis of incense ranged from 840 to 2,900 μg stick⁻¹, which was higher than the fragrance emission concentrations. Field observations in three temples and four rooms revealed that incense burning during memorial services presented a benzene cancer risk of 3.7–5.2 × 10⁻⁶ for monks. The seating position of the monk should be at least 11 m from the incense to reduce the cancer risk of benzene to a value below 1 × 10⁻⁶.