Development of Atmospheric Chemistry Instrumentation

该补助金提供了四个方面的研究：（1）测试 的独立校准方法，以扩大应用 自由基探测器（PERCA;见下文），范围更广 烃过氧自由基，沿着的改进， 检测器本身;（2）进一步优化现有的 用于涡流相关测量的快速臭氧监测器;（3） 大气气相色谱仪的研制 二氧化氮和PAN（过氧乙酰硝酸酯）;（4） 开发用于测量分子响应的系统 物种暴露于光（“j值”）。 PERCA是“过氧自由基检测器”的首字母缩写， 化学放大“测量的主要对象是 由附着的一种化学物质形成的瞬态化学物质， 氢原子与氧分子（式：H 0）。 下 2 这些分子在大气条件下 在阳光的照射下产生， 在化学反应中被破坏。 一个微小的浓度可能是 然而，持续的，足以赋予H 0一个重要的 2 在氧化其他痕量物质中的作用，例如，一氧化氮（NO）。 因此，能够测量这些低水平是很重要的 HO及其烃衍生的类似物，以便 2 构建总数的有效数学表示 大气化学系统 Perca现在已经投入使用，但 需要进一步的校准研究，以扩大其 使用范围更广的过氧自由基。 一个快速臭氧监测仪现已投入使用，但拟议的 优化旨在开发更简单的设备 重量更轻，更适合飞机测量， 臭氧在大气中的向上或向下流动。 PAN/NO色谱仪是一种现场测量 2 这些氮化合物。 PAN是一种“储库”物种， 大气中的活性氮， 生物学特性 二氧化氮是一种主要的载体 大气光化学系统中的光能。 用于测量“j值”的系统将用于关联 大气光化学变化的进程 可变光强驱动力。

This grant provides for four lines of research: (1) The testing of independent calibration methods to broaden the application of a free radical detector (the PERCA; see below) to a wider range of hydrocarbon peroxy radicals, along with improvements in the detector itself; (2) the further optimization of an existing fast ozone monitor for eddy correlation measurements; (3) the development of a gas chromatograph for measuring atmospheric nitrogen dioxide and PAN (peroxyacetyl nitrate); (4) the development of systems for measuring the response of molecular species to exposure to light ("j values"). PERCA is the acronym for a "peroxy radical detector using chemical amplification." The principal object of measurement is the transient chemical species formed by the attachment of a hydrogen atom to an oxygen molecule (formula: H0 ). Under 2 atmospheric conditions these molecules are constantly being produced in the presence of sunlight, and also constantly being destroyed in chemical reactions. A minute concentration may be sustained, however, sufficient to confer on H0 an important 2 role in oxidizing other trace species, e.g., nitric oxide (NO). It is therefore important to be able to measure these low levels of HO and of its hydrocarbon-derived analogues in order to 2 construct valid mathematical representations of the total atmospheric chemical system. The PERCA is now operational, but further calibration studies are needed in order to extend its use to a wider range of peroxy radicals. A fast ozone monitor is now operational, but the proposed optimization is directed to the development of a simpler device of lighter weight better adapted to aircraft measurements of upward or downward fluxes of ozone through the atmosphere. The PAN/NO chromatograph is a device for field measurement of 2 these nitrogen compounds. PAN is a "reservoir" species for active nitrogen in the atmosphere and it has deleterious biological properties. Nitrogen dioxide is a principal carrier of light energy in atmospheric photochemical systems. The system for measuring "j values" will find use in correlating the progress of atmospheric photochemical changes with the driving force of variable light intensity.