Bagley S T, Dorie L D, Leddy D G, Johnson J H
Dept. of Biological Sciences, Michigan Technological Univ., Houghton 49931.
Res Rep Health Eff Inst. 1987 Jan(5):1-67.
Diesel exhaust particles and vapor phase samples were collected from the diluted (15:1) exhaust of a 10.4 L displacement medium-duty engine (Caterpillar 3208), operated under EPA steady-state cycle Modes 4 and 5 conditions for load (50 and 75 percent, respectively) and speed (1680 rpm). Baseline (uncontrolled) emissions were compared to the exhaust modified by the use of an uncatalyzed monolithic ceramic trap (Corning). The Salmonella/microsome mutagenicity bioassay (Ames Test) was used to direct the course of chemical analyses. Total particulate matter (TPM), soluble organic fraction (SOF) (from TPM), sulfate fraction (SO4) (from TPM), and solid fraction (SOL) (from particle) were determined from dilute exhaust particles collected on 47 mm Teflon-coated woven glass fiber filters. Coincidentally, particles were collected on 508 x 508 mm Teflon-coated non-woven glass fiber filters, and vapor-phase samples were collected on XAD-2 resin. The SOF and VOC for chemical and biological characterization were obtained by Soxhlet extraction of samples with dichloromethane (DCM). Hydrocarbon mass balances were developed to evaluate the efficiency of the sampling system. Use of the ceramic traps caused no change in engine total hydrocarbon (HC) levels at Mode 4 but decreases in TPM, SOF, and NO2 were noted. In terms of HC emissions only, the percentage of SOF was significantly reduced, but the percentage of VOC was unchanged. For Mode 5, the engine HC levels were significantly reduced but the proportions of HC components, i.e. the percentage of SOF and the percentage of VOC, did not change significantly. Engine emission levels of TPM, SOF, and nitrogen dioxide (NO2) were also significantly reduced at Mode 5. At both Modes 4 and 5, use of the ceramic particle traps caused an increase in the direct-acting (TA98) mutagenicity (revertants/microgram) of the SOF and a decrease in the activity of the VOC. The traps caused a 70 percent reduction of TPM at Mode 4 but only a 45 percent reduction in particulate-associated direct-acting mutagenicity on the basis of raw exhaust emissions (kRevertants/m3). At Mode 5 with the traps, there was an 85 percent reduction in TPM and only a 25 percent reduction in the activity of the SOF. The direct-acting mutagenicity of the VOC was reduced by use of the traps by 40 and 65 percent (kRevertants/m3) for Modes 4 and 5, respectively. In contrast, the indirect-acting mutagenicity of the Mode 4 VOC increased nearly 150 percent. Filter loading and reexposure experiments indicated that sampling artifacts did not contribute to the SOF mutagenicity at Mode 4.(ABSTRACT TRUNCATED AT 400 WORDS)
从一台排量为10.4升的中型发动机（卡特彼勒3208）稀释（15:1）尾气中采集柴油尾气颗粒和气相样本，该发动机按照美国环保署稳态循环模式4和模式5的条件运行，负载分别为50%和75%，转速为1680转/分钟。将基线（未控制）排放与使用未催化的整体式陶瓷捕集器（康宁公司）改性后的尾气进行比较。采用沙门氏菌/微粒体诱变性生物测定法（艾姆斯试验）指导化学分析过程。从收集在47毫米涂有特氟龙的玻璃纤维编织滤膜上的稀释尾气颗粒中测定总颗粒物（TPM）、可溶性有机部分（SOF）（来自TPM）、硫酸盐部分（SO4）（来自TPM）和固体部分（SOL）（来自颗粒）。同时，将颗粒收集在508×508毫米涂有特氟龙的无纺玻璃纤维滤膜上，气相样本收集在XAD - 2树脂上。通过用二氯甲烷（DCM）对样品进行索氏提取获得用于化学和生物学表征的SOF和挥发性有机化合物（VOC）。建立了碳氢化合物质量平衡以评估采样系统的效率。使用陶瓷捕集器在模式4下未导致发动机总碳氢化合物（HC）水平变化，但注意到TPM、SOF和二氧化氮（NO2）有所降低。仅就HC排放而言，SOF的百分比显著降低，但VOC的百分比未变。对于模式5，发动机HC水平显著降低，但HC成分的比例，即SOF的百分比和VOC的百分比，没有显著变化。在模式5下，发动机的TPM、SOF和二氧化氮（NO2）排放水平也显著降低。在模式4和模式5下，使用陶瓷颗粒捕集器均导致SOF的直接作用（TA98）诱变性（回复突变体/微克）增加，VOC的活性降低。捕集器在模式4下使TPM降低了70%，但基于原始尾气排放（千回复突变体/立方米），颗粒相关直接作用诱变性仅降低了45%。在模式5下使用捕集器时，TPM降低了85%，SOF的活性仅降低了25%。使用捕集器使模式4和模式5下VOC的直接作用诱变性分别降低了40%和65%（千回复突变体/立方米）。相比之下，模式4下VOC的间接作用诱变性增加了近一倍半。滤膜负载和再暴露实验表明，采样假象对模式4下的SOF诱变性没有影响。（摘要截于400字）
