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首页> 外文会议>Fourth Conference on Atmospheric Chemistry: Urban, Regional, and Global Scale Impacts of Air Pollutants, Jan 13-17, 2002, Orlando, Florida >OZONE PRODUCTION EFFICIENCY AT THE WILLIAMS TOWER
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OZONE PRODUCTION EFFICIENCY AT THE WILLIAMS TOWER

机译：威廉姆斯大厦的臭氧生产效率

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摘要

One of the monitoring sites established for the Texas 2000 Air Quality Study was on the 62nd floor of the Williams Tower Building in the Uptown Galleria area of western Houston (Figure 1). There were several reasons for establis hing this site. At 830 feet above the ground, the 62nd floor is well above localized surface sources that often complicate the interpretation of observations from ground-level stations. And because the Williams Tower is at the western edge of the city (Figure 2), easterly flow was anticipated to esult in sampling air that had recently passed over the major emissions of greater Houston, providing an integrated measure of the chemical mix coming from this highly industrialized area. Observations from Williams Tower provide an excellent data set to evaluate a number of quantities related to the production of ozone. The first analysis we have done is to evaluate the efficiency by which ozone is produced in a parcel of air from the oxidation of NO_x (=NO + NO2) or, equivalently, the number of molecules of ozone produced per molecule of NO_x. The oxidation of NOx results not only in the production of O_3, but also a variety of other compounds including PAN, HNO_3 and HONO. Because ozone production efficiency, or "OPE," is a measure of the anticipated efficacy of NO_x control strategies as part of broader emission reduction scenarios, it is of considerable practical interest. A small OPE is indicative of relatively inefficient chemical production of O_3 from volatile organic compounds (VOCs) and NO_x, whereas a large OPE indicates a comparatively efficient system. Local emissions and meteorology can play a major role in defining the OPE. For this reason, estimates of OPE vary widely from place to place. Studies of urban plumes in the southeast United States suggest an OPE ～5―6, whereas in the drier climate of the southwestern United States, values are typically of order 3. It is important to note that OPE is a Lagrangian quantity; it applies to the changes resulting from chemical processes within a single parcel of air. For this reason we limit our analysis to periods of light winds and the relatively rapid onset of high ozone mixing ratios assuming that a single, albeit very large, air parcel is stationary over the Williams Tower, and that observed changes at this site during the selected study periods are predominantly a result of local chemical processes. Equivalently, we assume that the increases of ozone from one 15-minute period to the next under these conditions are a result of NO_x/VOC oxidation. During these intervals the loss of NO_x can be evaluated by the production rate of its oxidation products "NO_z," quantified as [PAN] + [HNO_3] +.[HONO].
机译：德克萨斯州2000年空气质量研究的监测站点之一位于休斯顿西部Uptown Galleria地区Williams Tower大楼的62层（图1）。建立该网站有几个原因。位于地面830英尺处的第62层远高于局部地表源，这通常会使来自地面站的观测结果的解释复杂化。而且由于威廉姆斯大厦位于城市的西部边缘（图2），预计向东流动会产生采样空气，该空气最近经过大休斯顿的主要排放物，从而提供了对由此产生的化学混合物的综合测量高度工业化的地区。威廉姆斯大厦的观测数据提供了一个极好的数据集，可评估与臭氧生产有关的许多数量。我们已经进行的第一个分析是评估由NO_x（= NO + NO2）的氧化或同等地每个NO_x分子产生的臭氧分子数，在空气中产生臭氧的效率。 NOx的氧化不仅导致O_3的产生，而且还导致包括PAN，HNO_3和HONO在内的各种其他化合物的产生。由于臭氧生产效率或“ OPE”是对NO_x控制策略作为更广泛的减排方案的一部分的预期功效的衡量标准，因此它具有很大的实际意义。小OPE表示从挥发性有机化合物（VOC）和NO_x生成O_3的化学效率相对较低，而大OPE则表示相对高效的系统。当地排放量和气象学可以在定义OPE方面发挥重要作用。因此，不同地区的OPE估算值差异很大。美国东南部城市羽流的研究表明OPE约为5-6，而在美国西南部较干燥的气候中，值通常为3阶。重要的是要注意OPE是拉格朗日量。它适用于单个空气中化学过程导致的变化。因此，我们将分析限制在微风周期和较高的臭氧混合比的相对较快的发生，假设单个（尽管非常大）空气包裹在威廉姆斯大厦上方静止不动，并且观察到在选定的时间内该地点的变化研究时期主要是局部化学过程的结果。等效地，我们假设在这些条件下，从一个15分钟的时间段到下一个15分钟的时间段内，臭氧的增加是NO_x / VOC氧化的结果。在这些时间间隔内，NO_x的损失可以通过其氧化产物“ NO_z”的生产速率来评估，其量化为[PAN] + [HNO_3] +。[HONO]。

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