• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Pure and Applied Geophysics >Assessing the Comparability of Ammonium, Nitrate and Sulfate Concentrations Measured by Three Air Quality Monitoring Networks
【24h】

Assessing the Comparability of Ammonium, Nitrate and Sulfate Concentrations Measured by Three Air Quality Monitoring Networks

机译：评估由三个空气质量监测网络测得的铵，硝酸盐和硫酸盐浓度的可比性

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

Airborne fine particulate matter across the United States is monitored by different networks, the three prevalent ones presently being the Clean Air Status and Trend Network (CASTNet), the Interagency Monitoring of PROtected Visual Environment Network (IMPROVE) and the Speciation and Trend Network (STN). If combined, these three networks provide speciated fine particulate data at several hundred locations throughout the United States. Yet, differences in sampling protocols and samples handling may not allow their joint use. With these concerns in mind, the objective of this study is to assess the spatial and temporal comparability of the sulfate, nitrate and ammonium concentrations reported by each of these networks. One of the major differences between networks is the sampling frequency they adopted. While CASTNet measures pollution levels on seven-day integrated samples, STN and IMPROVE data pertain to 24-hour samples collected every three days. STN and IMPROVE data therefore exhibit considerably more short-term variability than their CASTNet counterpart. We show that, despite their apparent incongruity, averaging the data with a window size of four to six weeks is sufficient to remove the effects of differences in sampling frequency and duration and allow meaningful comparison of the signals reported by the three networks of concern. After averaging, all the sulfate and, to a lesser degree, ammonium concentrations reported are fairly similar. Nitrate concentrations, on the other hand, are still divergent. We speculate that this divergence originates from the different types of filters used to collect particulate nitrate. Finally, using a rotated principal component technique (RPCA), we determined the number and the geographical organization of the significant temporal modes of variation (clusters) detected by each network for the three pollutants of interest. For sulfate and ammonium, the clusters’ geographical boundaries established for each network and the modes of variations within each cluster seem to correspond. RPCA erformed on nitrate concentrations revealed that, for the CASTNet and IMPROVE networks, the modes of variation do not correspond to unified geographical regions but are found more sporadically. For STN, the clustered areas are unified and easily delineable. We conclude that the possibility of jointly using the data collected by CASTNet, IMPROVE and STN has to be weighed pollutant by pollutant. While sulfate and ammonium data show some potential for joint use, at this point, combining the nitrate data from these monitoring networks may not be a judicious choice.
机译：美国各地的空气中细颗粒物由不同的网络监控，目前最流行的三个是清洁空气状态和趋势网络（CASTNet），受保护的视觉环境网络的机构间监视（IMPROVE）和物种形成和趋势网络（STN） ）。如果结合使用，这三个网络将在美国数百个地点提供特定的细颗粒数据。但是，采样方案和样品处理方面的差异可能不允许它们共同使用。考虑到这些问题，本研究的目的是评估每个网络报告的硫酸盐，硝酸盐和铵盐浓度的时空可比性。网络之间的主要区别之一是它们采用的采样频率。虽然CASTNet在7天的综合样本中测量污染水平，但STN和IMPROVE数据与每三天收集的24小时样本有关。因此，STN和IMPROVE数据比CASTNet对应数据显示出更大的短期可变性。我们显示，尽管它们之间存在明显的不一致，但对窗口大小为四到六周的数据进行平均足以消除采样频率和持续时间差异的影响，并能够对三个相关网络所报告的信号进行有意义的比较。平均后，报告的所有硫酸盐和较小的铵浓度都非常相似。另一方面，硝酸盐浓度仍存在差异。我们推测这种差异源自用于收集硝酸盐颗粒的不同类型的过滤器。最后，使用旋转主成分技术（RPCA），我们确定了每个网络针对感兴趣的三种污染物检测到的重要时间变化模式（簇）的数量和地理组织。对于硫酸盐和铵盐，为每个网络建立的簇的地理边界和每个簇内的变化模式似乎是相对应的。对硝酸盐浓度进行的RPCA分析表明，对于CASTNet和IMPROVE网络，变化模式并不对应于统一的地理区域，而更为零星地发现。对于STN，群集区域是统一的，并且易于划分。我们得出结论，必须共同使用CASTNet，IMPROVE和STN收集的数据来权衡污染物。尽管硫酸盐和铵盐数据显示了一些联合使用的潜力，但此时，将这些监测网络中的硝酸盐数据相结合可能不是明智的选择。

著录项

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