High Density Ozone Monitoring Using Gas Sensitive Semi-Conductor Sensors in the Lower Fraser Valley, British Columbia
High Density Ozone Monitoring Using Gas Sensitive Semi-Conductor Sensors in the Lower Fraser Valley, British Columbia
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DOI：
10.1021/es404610t
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发表时间：
2014-04-01
影响因子：
11.4
通讯作者：
Henshaw, Geoff S.
中科院分区：
文献类型：
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作者：
Bart, Mark;Williams, David E.;Henshaw, Geoff S.
2012年5月至9月，在不列颠哥伦比亚省下弗雷泽山谷的一个50个传感器试验台上部署和验证了一种利用气敏半导体氧化物技术、太阳能和自动手机通信进行精确地表臭氧监测的具有成本效益的技术。在现场部署之前，整套仪器与参考仪器共置至少48小时，比较每小时的平均数据。该组在0-50 ppb典型范围内的估计标准误差为3 +/- 2 ppb。通过将10台仪器的一个子集分别置于不同的参考点，在几个月内对长期准确性进行评估。每小时平均臭氧浓度的差异（GSS-参考）呈正态分布，平均值为-1ppb，6ppb的标准偏差（6000测量对）。使用网络相关性和对原始传感器电阻数据的一致性检查来检测现场的仪器故障。与模拟空间O-3领域的比较表明，一个网络，这是一个低成本和参考仪器，其中GSS传感器被用来增加网络内的站密度，以及扩展到偏远地区的监测混合增强的监测能力。这一雄心勃勃的部署暴露了一些挑战和教训，包括夏季部署和维护站点所需的后勤工作，以及手机通信和电池寿命的不足。远程站点的仪器故障表明，应在网络中建立冗余（特别是在关键站点），并可能为全球安全系统监测器增加“睡眠模式”。在网络设计阶段，建议采用更客观的方法来优化站间距离和网络的“信息”内容。这项研究已经证明了GSS技术在各种应用中的实用性和可负担性，以及这种技术作为一种手段的有效性，大大和经济地扩大了空气质量监测网络的覆盖范围。可以设想产生可靠数据的低成本、社区规模的网络。
A cost-efficient technology for accurate surface ozone monitoring using gas-sensitive semiconducting oxide (GSS) technology, solar power, and automated cell-phone communications was deployed and validated in a 50 sensor test-bed in the Lower Fraser Valley of British Columbia, over 3 months from May-September 2012. Before field deployment, the entire set of instruments was colocated with reference instruments for at least 48 h, comparing hourly averaged data. The standard error of estimate over a typical range 0-50 ppb for the set was 3 +/- 2 ppb. Long-term accuracy was assessed over several months by colocation of a subset of ten instruments each at a different reference site. The differences (GSS-reference) of hourly average ozone concentration were normally distributed with mean -1 ppb and standard deviation 6 ppb (6000 measurement pairs). Instrument failures in the field were detected using network correlations and consistency checks on the raw sensor resistance data. Comparisons with modeled spatial O-3 fields demonstrate the enhanced monitoring capability of a network that was a hybrid of low-cost and reference instruments, in which GSS sensors are used both to increase station density within a network as well as to extend monitoring into remote areas. This ambitious deployment exposed a number of challenges and lessons, including the logistical effort required to deploy and maintain sites over a summer period, and deficiencies in cell phone communications and battery life. Instrument failures at remote sites suggested that redundancy should be built into the network (especially at critical sites) as well as the possible addition of a "sleep-mode" for GSS monitors. At the network design phase, a more objective approach to optimize interstation distances, and the "information" content of the network is recommended. This study has demonstrated the utility and affordability of the GSS technology for a variety of applications, and the effectiveness of this technology as a means substantially and economically to extend the coverage of an air quality monitoring network. Low-cost, neighborhood-scale networks that produce reliable data can be envisaged.