Wang Linlin, Thompson Tammy, McDonald-Buller Elena C, Webb Alba, Allen David T
Center for Energy and Environmental Resources, The University of Texas at Austin, Austin, Texas 78758, USA.
Environ Sci Technol. 2007 Apr 1;41(7):2095-102. doi: 10.1021/es061273i.
As part of the State Implementation Plan for attaining the National Ambient Air Quality Standard for ozone, the Texas Commission of Environmental Quality has created a Highly Reactive Volatile Organic Compounds (HRVOC) Emissions Cap and Trade Program for industrial point sources in the Houston/Galveston/Brazoria area. This program has a number of unique features, including its focus on a limited group of ozone precursors and its provisions for trading emissions based on atmospheric reactivity. This series of papers examines the potential air quality impacts of this new emission trading program through photochemical modeling of potential trading scenarios; this first paper in the series describes the air quality modeling methods used to assess potential trades, the potential for localized increases in ozone concentrations (ozone "hot spots") due to HRVOC emission trading, and the use of reactivity scales in the trading. When HRVOC emissions are traded on a mass basis, the simulations indicate that trading of HRVOC allowances between facilities resulted in less than 0.15 ppb (<0.13%) and 0.06 ppb (<0.06%) increases in predicted maximum, area-wide 1-h averaged and 8-h averaged ozone concentrations, respectively. Maximum decreases in ozone concentrations associated with trading, as opposed to across-the-board reductions, were larger than the increases. All of these changes are small compared to the maximum changes in ozone concentrations due to the VOC emissions from these sources (up to 5-10 ppb for 8 h averages; up to 30 ppb for 1-h averages). When emissions of HRVOCs are traded for other, less reactive emissions, on a reactivity weighted basis, air quality simulations indicate that daily maximum ozone concentrations increased by less than 0.3%. Because these relatively small changes (< 1%) are for unlikely trading scenarios designed to produce a maximum change in ozone concentrations (all emissions traded into localized regions), the simulations indicate that the implementation of the trading program, as currently configured and possibly expanded, is unlikely to cause localized increases in ozone concentrations ("hot spots").
作为实现国家臭氧环境空气质量标准的州实施计划的一部分，得克萨斯州环境质量委员会为休斯顿/加尔维斯顿/布拉佐里亚地区的工业点源创建了一个高反应性挥发性有机化合物（HRVOC）排放总量控制与交易计划。该计划有许多独特之处，包括专注于有限的一组臭氧前体，以及基于大气反应性的排放交易规定。本系列论文通过对潜在交易情景的光化学建模，研究了这个新的排放交易计划对空气质量的潜在影响；本系列的第一篇论文描述了用于评估潜在交易的空气质量建模方法、由于HRVOC排放交易导致臭氧浓度局部升高（臭氧“热点”）的可能性，以及交易中反应性尺度的使用。当按质量基础交易HRVOC排放时，模拟结果表明，设施之间的HRVOC配额交易导致预测的最大、区域范围1小时平均和8小时平均臭氧浓度分别增加不到0.15 ppb（<0.13%）和0.06 ppb（<0.06%）。与全面减排相比，与交易相关的臭氧浓度最大降幅大于增幅。与这些源的VOC排放导致的臭氧浓度最大变化相比（8小时平均值高达5 - 10 ppb；1小时平均值高达30 ppb）,所有这些变化都很小。当按反应性加权基础将HRVOC排放与其他反应性较低的排放进行交易时，空气质量模拟表明，每日最大臭氧浓度增加不到0.3%。由于这些相对较小的变化（<1%）是针对旨在使臭氧浓度产生最大变化的不太可能的交易情景（所有排放交易到局部区域），模拟结果表明，按照目前配置并可能扩大的交易计划实施，不太可能导致臭氧浓度局部升高（“热点”）。
