Characteristics and Toxic Equivalent Dose of Pahs Released From the Combustion of Moxa-like Substances
The combustion of moxa produces pollutants such as particulate matter,volatile organic compounds,and Polycyclic Aromatic Hydrocarbons(PAHs),and PAHs are usually carcinogenic,teratogenic,and mutagenic.To understand the emission characteristics of PAHs released by burning moxa and protect human health,in this paper,six types of moxa sticks(two sticks per type)and two types of moxa columns(16 columns per type)were burned inside a clean environment chamber.The solid phase(PM2.5)PAHs released from the smoke of each moxa type were sampled and collected.The samples after the pre-treatment were subjected to GC-MS on-board analysis to obtain the emission characteristics and toxicity of PAHs(PM2.5).The following conclusions were obtained:1)The emission factor of PAHs(PM2.5)from moxa sticks(columns)ranged from 2.097 to 6.135 μg/g.Regarding moxa sticks with the same composition,the same storage year,but different purification ratios,the smaller the purification ratio resulted in the smaller emission factor of PAHs(PM2.5).2)The moxa sticks with the same purification and composition but stored for longer period of year leaded to smaller emission factor of PAHs(PM2.5).The Chinese herb in moxa sticks significantly reduces the emission factor.3)The PAHs released from moxa sticks and columns(PM2.5)are mainly composed of three-ring and four-ring PAHs,accounting for 41.64％-45.49％and 39.19％-41.74％respectively,with the lowest percentage being two-ring PAHs.Phenanthrene is the dominant individual PAHs, accounting for 19. 54％ - 29. 65％, followed by anthracene, fluoranthene, and pyrene. 4) The Benzo[ a] pyrene Equivalence (BEQs) of PAHs ranged from 113. 579 to 829.107 ng/g, and the total Mutagenic Equivalence (MEQs) ranged from 121.001 to 940. 311 ng/g. The moxa sticks with the same purification ratio and composition but stored for a shorter year had higher carcinogenic and mutagenic toxicity. The moxa sticks with the same storage year and composition but having higher purification ratio resulted in smaller carcinogenic and mutagenic toxicity. Traditional Chinese medicine-type moxa sticks have lower carcinogenic and mutagenic toxicity than the common type.
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