Emission identification and health risk potential of allergy-causing fragrant substances in PM2.5 from incense burning

Abstract We investigated the emission characteristics of the allergenic aromatics eugenol and related compounds and vanillin from the incense powder and the PM 2.5 emitted from burning Hsin Shan (HSIN), Shang Chen (SC), Shang Lao Shan (SLS) and Lao Shang Tou (LST) incense sticks. The powder produced 590.7–72.5 μg of fragrant compounds g −1 of incense powder, ranking HSIN >> SLS > LST ∼ SC, with vanillin representing 65.83–71.46% of the total, while the PM 2.5 produced a higher 870.8–593.7 μg of fragrant compounds g −1 of incense, ranking HSIN >> SC >> LST > SLS, with methyl isoeugenol the most prevalent compound, at 48.13–56.59% of the total, followed by vanillin. Burning caused some transformation of isoeugenol and methyl isoeugenol into the cis -type and hence both trans and cis types were present in the PM 2.5 . The ratio of total fragrant compounds in smoke PM 2.5 to the content per gram of incense powder (IPt ratio) in the four types of incense ranged from 1.153 (SLS) to 1.507 (SC), indicating that incense powder produces a substantial amount of total fragrant compounds when burned. The ratio of fragrant emission factors in smoke PM 2.5 to the content per gram of incense powder (IPs ratio) of methyl eugenol, vanillin, and eugenol was