Ozone-initiated reactions with mixtures of volatile organic compounds under simulated indoor conditions
Ozone-initiated reactions with mixtures of volatile organic compounds under simulated indoor conditions
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DOI：
10.1021/es026231i
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发表时间：
2003-05-01
影响因子：
11.4
通讯作者：
Zhang, JF
中科院分区：
文献类型：
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作者：
Fan, ZH;Lioy, P;Zhang, JF
这项研究考察了将臭氧添加到挥发性有机化合物(VOC)的复杂混合物中引发的反应所产生的初级和次级产品。这些混合物代表了通常在室内发现的有机物种，但其浓度往往高于室内正常水平。每个4小时的实验都在受控环境设施(CEF，25m(3))中进行，通风时间类似于1.8h(-1)。所研究的混合物包括23种VOC(无O-3)、O-3/23 VOC、O-3/21 VOC(不含d-柠檬烯或a-蒎烯)和仅含O-3/萜烯(d-柠檬烯和a-蒎烯)的混合物。在每个实验中，净O-3浓度接近40 ppb，23种VOC混合物的总有机浓度为26 mg/m(3)，21种VOC混合物的总有机浓度为25 mg/m(3)，d-柠檬烯和α-蒎烯混合物的总有机浓度为1.7 mg/m(3)。当将23种VOC加入到不含O-3的CEF中时，没有观察到除故意引入的那些化合物外的其他化合物。当将O-3加入含有23种VOC混合物的CEF中时，发现了气相和凝聚相产物，包括醛、有机酸和亚微米颗粒(140mug/m(3))。当将O-3加入不含两个萜类的21VOC的CEF中时(O-3/21VOC条件)，03/23VOC实验中观察到的大多数产物不再存在或以低得多的浓度存在。此外，颗粒物质量浓度为2-7微克/立方米，与本底颗粒物浓度水平没有区别。在仅含两个萜类化合物的CEF中加入O-3，所得结果与O-3/23 VOC实验结果相似，但颗粒质量浓度(190µg/m(3))较高。结果表明：(I)在室内条件下，O-3与不饱和烯烃反应生成亚微米粒子和其他潜在刺激性物质，如醛和有机酸；(Ii)在我们的实验条件下发生的主要化学转化是由O-3/d-柠檬烯和Ova-Pinene反应驱动的；(Iii)O-3/萜烯反应产生的羟基在化学转化中起重要作用，约占这些实验中产生的甲醛、几乎所有对甲苯醛和19-29%的颗粒物质量的56%-70%。
This study examines the primary and secondary products resulting from reactions initiated by adding ozone to complex mixtures of volatile organic compounds (VOC). The mixtures were representative of organic species typically found indoors, but the concentrations tended to be higher than normal indoor levels. Each 4-h experiment was conducted in a controlled environmental facility (CEF, 25 m(3)) ventilated at similar to1.8 h(-1). The mixture investigated included 23 VOC (no O-3), O-3/23 VOC, O-3/21 VOC (no d-limonene or a-pinene), and O-3/terpene only (d-limonene and a-pinene). The net O-3 concentration was similar to40 ppb in each experiment, and the total organic concentration was 26 mg/m(3) for the 23 VOC mixture, 25 mg/m(3) for the 21 VOC mixture, and 1.7 mg/m(3) forthe d-limonene and alpha-pinene mixture. When the 23 VOC were added to the CEF containing no O-3, no compounds other than those deliberately introduced were observed. When O-3 was added to the CEF containing the 23 VOC mixture, both gas and condensed phase products were found, including aldehydes, organic acids, and submicron particles (140 mug/m(3)). When O-3 was added to the CEF containing the 21 VOC without the two terpenes (O-3/21 VOC condition), most of the products that were observed in the 03/23 VOC experiments were no longer present or present at much lower concentrations. Furthermore, the particle mass concentration was 2-7 mug/ m3, indistinguishable from the background particle concentration level. When O-3 was added to the CEF containing only two terpenes, the results were similar to those in the O-3/23 VOC experiments, but the particle mass concentration (190 mug/m(3)) was higher. The results indicate that (i) O-3 reacts with unsaturated alkenes under indoor conditions to generate submicron particles and other potentially irritating species, such as aldehydes and organic acids; (ii) the major chemical transformations that occurred under our experimental conditions were driven by O-3/d-limonene and Ova-pinene reactions; and (iii) the hydroxyl radicals (OH) that were generated from the O-3/terpene reactions played an important role in the chemical transformations and were responsible for approximately 56-70% of the formaldehyde, almost all of the p-tolualdehyde, and 19-29% of the particle mass generated in these experiments.