• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Changes in ozone sensitivity to precursor emissions on diurnal, weekly, and decadal time scales.
【24h】

Changes in ozone sensitivity to precursor emissions on diurnal, weekly, and decadal time scales.

机译：臭氧对前驱物排放的敏感性在每日，每周和十年时间尺度上变化。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Despite efforts to improve air quality over the past several decades, ozone remains a stubborn threat to human health, agriculture, and forests. Emissions of the ozone precursors—volatile organic compounds (VOC) and nitrogen oxides (NOx)—have been affected by regulation and growth in population, transportation, and industry.; Spatial and temporal variations in ambient pollutant concentrations contain information that has been overlooked by the regulatory-driven focus on one-hour maxima at individual monitoring sites. This work describes the history and spatial distribution of day-of-week differences in ozone and precursor concentrations through the analysis of two decades of observations from sites located throughout California.; Emission inventories, especially for motor vehicles, are a large source of uncertainty in current models of photochemical air pollution. Improved estimates of motor vehicle emissions in 1990 and 2000, containing weekend-specific descriptions of vehicle activity, have been developed as part of this research. Emissions of VOC and NOx from motor vehicles are ∼5 and ∼25% lower on weekends compared to weekdays; the 70–80% drop in heavy-duty diesel truck traffic on weekends is the main source of weekday-weekend differences in NOx emissions. Reductions in NOx emissions from light-duty gasoline-powered vehicles have been offset by large increases in diesel truck traffic and a lack of improvement in the diesel truck emission factor for NOx.; Photochemical modeling provides further insight into spatial and temporal variations in ozone sensitivity to precursor emissions. This photochemical modeling study is the first to use an emission inventory that describes the different temporal patterns of diesel trucks versus cars by hour and day of week. The reduced activity of heavy-duty diesel trucks, an important source of NOx, on weekends is shown to be a primary cause of higher weekend ozone concentrations. Modeling results also show that long-term changes in emissions patterns have resulted in a shift towards increasing VOC-sensitivity. This shift, combined with the increased contribution of heavy-duty diesel trucks to the emission inventory and correspondingly larger weekday-weekend difference in NOx emissions, explains why the weekend ozone effect has spread throughout California between 1980 and the present.; The major implications of this work are that a disproportionate share of exposure to ozone occurs on weekends and that weekday-weekend differences in ambient ozone concentrations can be used as a diagnostic tool to help determine whether ozone formation in an area is VOC- or NOx-sensitive. Ozone formation cannot be considered in isolation of other air quality problems. (Abstract shortened by UMI.)
机译：尽管过去几十年来一直在努力改善空气质量，但臭氧仍然是对人类健康，农业和森林的顽固威胁。臭氧前体（挥发性有机化合物（VOC）和氮氧化物（NO x ））的排放受到人口，运输和工业的管制和增长的影响。环境污染物浓度的时空变化所包含的信息已被监管机构所关注的单个监测点的最大一小时最大值所忽略。这项工作是通过对整个加利福尼亚州各地二十年来的观测结果进行分析来描述臭氧和前驱物浓度周日差异的历史和空间分布。在当前的光化学空气污染模型中，排放清单（尤其是汽车的排放清单）是很大的不确定性来源。作为这项研究的一部分，已经对1990年和2000年的机动车排放进行了改进的估算，其中包含周末特定的机动车活动描述。与工作日相比，周末汽车排放的VOC和NO x 分别降低了约5％和约25％。周末重型柴油卡车运输量下降70-80％是NO x 排放量在工作日与周末之间差异的主要原因。轻型汽油车的NO x 排放量的减少已被柴油卡车运输量的大幅度增加以及NO x .;光化学模型可进一步了解臭氧对前体排放的敏感性的时空变化。这项光化学模型研究首次使用了排放清单，该清单按小时和星期几描述了柴油卡车与汽车的不同时间模式。周末，重型柴油卡车（NO x 的重要来源）的活动减少是周末臭氧浓度升高的主要原因。建模结果还表明，排放模式的长期变化已导致向VOC敏感性增强的转变。这种转变，再加上重型柴油卡车对排放清单的贡献增加以及相应的工作日/周末NO x 排放差异更大，这解释了为什么周末的臭氧效应在1980年至2006年期间遍及整个加利福尼亚现在。这项工作的主要含义是，周末发生的臭氧暴露比例不成比例，并且工作日与周末之间的环境臭氧浓度差异可以用作诊断工具，以帮助确定该地区的臭氧形成是VOC还是NO < sub> x 敏感。不能孤立其他空气质量问题来考虑臭氧的形成。 （摘要由UMI缩短。）

著录项

  • 作者

    Marr, Linsey Chen.;

  • 作者单位

    University of California, Berkeley.;

  • 授予单位 University of California, Berkeley.;
  • 学科 Engineering Environmental.; Environmental Sciences.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 213 p.
  • 总页数 213
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;环境科学基础理论;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号