MUTAGENS IN AMBIENT AIRBORNE ORGANIC AEROSOLS--IDENTITY AND SOURCES

这项研究的目的是确定最 大气颗粒物中存在的重要致突变化合物 利用新开发的人体细胞， 测定。 最重要诱变剂浓度的结果 环境有机气溶胶和源样品将用于跟踪 这些化合物的来源 该研究最初将涉及 环境有机颗粒物样本代表了 的季节条件和空间污染物梯度的范围， 严重污染了洛杉矶地区大气。 生物测定导向化学品 分析将用于确定最重要的身份 诱变剂 研究的一个组成部分将是确定 大气变化对大气成分的影响， 最重要的诱变剂的浓度。 一种大气测量方法 转换是观察到的大气之间的差异 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 可以使用以下大气传输模型获得 从源头或分子示踪技术分散。 另一 通过主要诱变剂在以下之间的分布提供测量： 大气中细微气溶胶的不同粒径。 粒径在0.05至0.5 μ m范围内的颗粒代表主要的 而尺寸范围为0.5至2.0 μ m的颗粒具有 在大气中发生大气反应和凝聚。 一个 了解多环芳烃的分配及其大气 转换产品对于解释数据非常重要， 最重要的诱变剂在不同大小之间的分布 分数 部分人细胞试验的初步结果， 通过梯度洗脱液相色谱法获得， 在加利福尼亚州洛杉矶、密苏里州圣刘易斯和华盛顿收集的颗粒， DC，表明多环芳烃（PAH）及其硝基 衍生物是两类化合物，占显着 观察到的突变。 虽然PAH主要是由 燃烧源，硝基取代的PAH可以存在于 燃烧室的主要流出物或燃烧产生的主要流出物- 通过大气反应生成PAH。 PAH的形成机制 及其衍生物将被研究，以帮助区分 燃烧和大气途径硝基取代的多环芳烃以及 为了解释观察到的高特异性致突变性（突变体 每微克有机碳的分数）的某些燃烧源 (e.g.,天然气设备）。 机制的关键是测量 多环芳烃激进分子的火焰。 结果的可转移性 洛杉矶至其他地点，在适当考虑到 主要有机排放源的数量差异， 对于分散和大气化学的差异，将进行评估 通过研究来自纽约州罗切斯特两个地点的样本， Woburn，MA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.