MUTAGENS IN AMBIENT AIRBORNE ORGANIC AEROSOLS--IDENTITY AND SOURCES

拟议研究的目标是确定最多的 大气颗粒物中存在的重要致突变化合物 利用新开发的人类细胞对物质和城市污染源污水进行处理 化验。关于最重要的诱变剂浓度的结果 将使用周围的有机气溶胶和来源样本来跟踪 这些化合物回到了它们的源头。研究最初将涉及 环境中具有代表性的有机颗粒物样品 的季节状况和空间污染物梯度的范围 污染严重的洛杉矶地区大气。生物测定导向的化学物质 分析将被用来确定最重要的身份 诱变剂。研究的一个组成部分将是确定 大气变化对化学成分和化学成分的影响 最重要的诱变剂的浓度。大气的一种测量方法 变化就是观测到的大气 最重要诱变剂的浓度和计算值 来自主要来源的贡献。计算值将为 使用下面的大气传输模型中的任一个来获得 从源头分散或分子示踪技术。另一个 测量是由初级诱变剂在以下两个区域之间的分布提供的 大气中细小气溶胶的不同大小。 大小在0.05微米到0.5微米之间的粒子代表原生粒子 流出物，而粒径在0.5至2.0微米之间的颗粒具有 在大气中经历了大气反应和凝聚。一个 对多环芳烃及其大气分配的认识 转换产品对于数据的解释非常重要 最重要的诱变剂在不同体型间的分布 分数。对组分进行人体细胞分析的初步结果， 通过梯度洗脱液层层析法获得的 在洛杉矶、加利福尼亚州、圣路易斯、密苏里州和华盛顿收集的颗粒物， DC，表明多环芳烃(PAH)及其硝基 衍生品是两类化合物，它们占重要的 观察到的突变的一部分。而多环芳烃主要是由 燃烧来源，硝基取代的多环芳烃可能存在于 从燃烧室排出的主要流出物或燃烧产生的- 大气反应生成的多环芳烃。多环芳烃的形成机理 将对其衍生产品进行研究，以帮助区分 硝基取代多环芳烃的燃烧途径和大气途径 为了解释观察到的高特异性突变性(突变体 每微克有机碳的分数)某些燃烧源 (如天然气用具)。机制的关键是测量 火焰中的多环芳烃自由基。结果的可转移性 洛杉矶至其他地点，在适当的考虑后 主要有机排放源和主要排放源的大小差异 对于弥散和大气化学的差异，将进行评估 通过研究来自纽约罗切斯特和纽约两个地点的样本 马萨诸塞州沃本和选定的室内样品。

The objectives of the proposed research are to determine the most important mutagenic chemical compounds present in atmospheric particulate matter and in urban source effluents using newly developed human cell assays. The results on concentrations of the most important mutagens in the ambient organic aerosols and source samples will be used to track those compounds back to their source. The research initially will involve ambient organic particulate matter samples representative of the full range of seasonal conditions and spatial pollutant gradients found in the heavily polluted Los Angeles area atmosphere. Bioassay-directed chemical analysis will be used to determine the identity of the most important mutagens. An integral part of the study will be the determination of the effect of atmospheric transformations on the composition and concentrations of the most important mutagens. One measure of atmospheric transformation is the difference between the observed atmospheric concentrations of the most important mutagens and the values calculated from the contributions of the primary sources. The calculated values will be obtained using either atmospheric transport models that follow dispersion from the sources or molecular tracer techniques. Another measure is provided by the distribution of the primary mutagens between the different size fractions of the fine aerosols in the atmosphere. Particles in the 0.05 to 0.5 mum size range are representative of primary effluents whereas particles in the size range of 0.5 to 2.0 mum have undergone atmospheric reactions and agglomeration in the atmosphere. An understanding of the partitioning of PAH and its atmospheric transformation products is important for the interpretation of the data on the distribution of the most important mutagen between the different size fractions. Preliminary results with human cell assays on fractions, obtained by gradient elution liquid chromatography, of extracts from particles collected in Los Angeles, CA, Saint Louis, MO, and Washington, DC, show that polycyclic aromatic hydrocarbons (PAH) and their nitro derivatives are two classes of compounds that account for a significant portion of the observed mutations. While the PAH are emitted primarily by combustion sources, the nitro-substituted PAH may be either present in the primary effluents from the combustors or be produced from combustion- generated PAH by atmospheric reactions. The mechanism of formation of PAH and its derivatives will be studied in order to help distinguish between the combustion and atmospheric pathways to nitro-substituted PAH as well as to explain the observation of high specific mutagenicity (mutant fraction per microgram of organic carbon) of certain combustion sources (e.g., natural gas appliances). Key to the mechanism is the measurement of the PAH radicals in flames. The transferability of the results from Los Angeles to other locations, after due allowance is made for differences in the magnitudes of the major sources of organic emission and for differences in dispersion and atmospheric chemistry, will be assessed by studying samples from two locations in each of Rochester, NY, and Woburn, MA, and selected indoor samples.