艾条和艾柱燃烧释放颗粒物PM_(1.0)中多环芳烃的散发特征及浓度预测

Emission Characteristics and Concentration Prediction of Polycyclic Aromatic Hydrocarbons(Pahs)in Particulate Matter PM_(1.0)Released By the Buring of Moxa Sticks and Pillars

为了解艾条和艾柱燃烧释放颗粒物PM_(1.0)中多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)的散发特征,选取具有不同储存年份和提纯比例的4种艾条和2种艾柱为研究对象,首先在换气次数为1次/h的8 m^(3)的洁净环境舱内分别点燃一定量的艾条或艾柱,等其燃烧结束并停止通风换气后对烟气中颗粒相PM_(1.0)进行采样,样品经提纯和GC-MS上机分析确定PM1.0中PAHs的含量。由PAHs含量确定艾条或艾柱燃烧释放PM_(1.0)中PAHs即(PM_(1.0))PAHs的最高浓度(也即平衡浓度),进而确定其散发因子和散发速率,分析艾条或艾柱固有的特征参数对PAHs散发量的影响,同时与来自文献的PM_(2.5)中PAHs的散发特征进行对比分析。对艾条和艾柱散发的(PM_(1.0))PAHs的毒性进行了分析,最后对不同体积及换气次数的实际房间苯并[a]芘的浓度进行预测。结果表明:(1)艾条和艾柱燃烧释放的(PM_(1.0))PAHs中的优势个体主要为菲、蒽和荧蒽,其中菲的平均占比达23.66%,4环PAHs(荧蒽、芘、苯并[a]蒽、)占比最高,达31.11%~61.49%,5环(苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘、二苯并[a,h]蒽)和6环(茚并[1,2,3-cd]芘、苯并[g,h,i]苝)占比较小,且随提纯比例增大或年份的降低而升高;(2)艾条和艾柱(PM1.0)PAHs的散发因子均值分别为2.99μg/g和4.62μg/g,散发速率均值为6.51μg/(h·g)和26.79μg/(h·g),随年份及提纯比例的减小,散发因子和散发速率有增大趋势;(3)(PM_(1.0))PAHs的散发因子在(PM_(2.5))PAHs中的占比为78.90%~85.28%,散发速率占比为78.91%~85.15%,且高环PAHs在(PM_(1.0))PAHs中的占比高于(PM_(2.5))PAHs;(4)(PM1.0)PAHs的致癌和致突变毒性等效剂量为107.14~526.56 ng/g和110.12~585.62 ng/g,5~6环PAHs的致毒贡献率最高,控制苯并[a]芘等致毒优势个体排放可有效降致毒风险;(5)提高换气次数或房间体积均可降低苯并[a]芘浓度。房间体积为60 m^(3)时,当换气次数为12次/h时预测的艾条和艾柱苯并[a]芘峰值浓度分别为2.75 ng/m^(3)和4.69 ng/m^(3)。换气次数为6次/h时,分别为5.19 ng/m^(3)和8.36 ng/m^(3)。推荐在换气次数为12次/h的通风条件下,以艾条进行艾灸。

To understand the emission characteristics of Polycyclic Aromatic Hydrocarbons(PAHs)in PM_(1.0) released from the combustion of moxa sticks and moxa pillars,four types of moxa sticks and two types of moxa pillars with different storage years and purification ratios were selected as the research objects.A specific quantity of moxa sticks or moxa pillars were firstly ignited in an 8 m^(3) clean environment chamber with an air change rate of 1/h.Upon completion of the combustion and cessation of ventilation,PM_(1.0)was sampled in the smoke.The samples were analyzed using purification and GC-MS online to determine the PAHs content in PM_(1.0).From the PAHs content,the highest concentration of PAHs in PM_(1.0)(PM_(1.0)(PAHs))was determined from the combustion of moxa sticks or moxa pillars,and then the emission factor and the emission rate were determined to analyze the influence of the inherent characteristic parameters of moxa sticks or moxa pillars on the dispersed PAHs,and at the same time,to make a comparative analysis with the characterization of the PAHs dispersal in PM_(2.5)from the literature.The toxicity of(PM_(1.0))PAHs emitted by moxa sticks and moxa pillars was analyzed,and the concentration of(PM_(1.0))PAHs in the actual moxa chamber with different volumes and air change rate was then predicted by simulation.The results showed that:(1)The dominant individuals in the(PM_(1.0))PAHs released from the combustion of moxa sticks and pillars were mainly phenanthrene,anthracene,and fluoranthene,with an average of 23.66%for phenanthrene.4 rings PAHs(Fluoranthene,Pyrene,Benzo[a]anthracene,and Chrysene)had the highest percentage,ranging from 31.11%to 61.49%.5 rings(Benzo[b]fluoranthene,Benzo[k]fluoranthene,Benzo[a]pyrene,and Dibenzo[a,h]anthracene)and 6 rings(Indeno[1,2,3-cd]pyrene and benzo[g,h,i]perylene)accounted for a relatively small proportion of the total and increased with increasing purification ratio or decreasing storage year.(2)The emission factors of(PM_(1.0))PAHs were 2.99μg/g and 4.62μg/g,respectively,for moxa sticks or moxa pillars,and the mean values of emission rate were 6.51μg/(h·g)and 26.79μg/(h·g),respectively.The emission factor and emission rate tended to increase with decreasing storage year and purification ratio.(3)The emission factors of(PM_(1.0))PAHs in(PM_(2.5))PAHs ranged from 78.90%to 85.28%,and the emission rate ranged from 78.91%to 85.15%,and the percentage of high ring PAHs in(PM_(1.0))PAHs was higher than that in(PM_(2.5))PAHs.(4)The carcinogenic toxicity equivalent dose of(PM_(1.0))PAHs ranged from 107.14 to 526.56 ng/g,and the equivalent dose of mutagenicity is 110.12~585.62 ng/g.The toxicity contribution of 5~6 rings PAHs is the highest.Controlling the emission of toxic dominant individuals,such as benzo[a]pyrene,can effectively reduce the risk of toxicity.(5)Increasing either the air change rate or the room volume reduced the benzo[a]pyrene concentration.The peak concentrations of benzo[a]pyrene were 2.75 ng/m^(3) and 4.69 ng/m^(3) for moxa sticks and moxa pillars,respectively,in a room of 60 m^(3)with an air change rate of 12/h.The peak concentrations of benzo[a]pyrene were 5.19 ng/m^(3) and 8.36 ng/m^(3) in a room with an air change rate of 6/h.It is recommended to perform moxibustion with moxa sticks in a ventilation condition with 12/h.