Integrated Chemistry of Ozone in the Atmosphere (ICOZA)

大气中臭氧综合化学（ICOZA）

• 批准号: NE/K012398/1
• 负责人: Claire Reeves
• 金额: $ 11.16万
• 依托单位: University of East Anglia
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK012398%2F1
• 关键词: Integrated; Chemistry; Ozone; Atmosphere; ICOZA

Tropospheric ozone is an important air pollutant, harmful to human health, agricultural crops and vegetation. It is the main precursor to the atmospheric oxidants which initiate the degradation of most reactive gases emitted to the atmosphere, and is an important greenhouse gas in its own right. As a consequence of this central role in atmospheric chemistry and air pollution, the capacity to understand, predict and manage tropospheric ozone levels is a key goal for atmospheric science research. This goal is hard to achieve, as ozone is a secondary pollutant, formed in the atmosphere from the complex oxidation of VOCs in the presence of NOx and sunlight, and the timescale of ozone production is such that a combination of in situ chemical processes, deposition and transport govern ozone levels. Uncertainties in all of these factors affect the accuracy of numerical models used to predict current and future ozone levels, and so hinder development of optimal air quality policies to mitigate ozone exposure. Here, we will address this problem by measuring the local chemical ozone production rate, and (for the first time) perform measurements of the response of the local atmospheric ozone production rate to NOx and VOC levels - directly determining the ozone production regime. We will achieve this aim by building upon an existing instrument for the measurement of atmospheric ozone production rates (funded through a NERC Technology Proof-of-Concept grant, and deployed in the recent ClearfLo "Clean Air for London" NERC Urban Atmospheric Science programme). In addition to directly measuring ozone production, by perturbing the ambient chemical conditions (for example, through addition of NOx or VOCs to the sampled airflow), and measuring the effect of this change upon the measured ozone production rate, the ozone control regime (extent of NOx vs VOC limitation) may be directly determined. Within this project, we will develop our existing ozone production instrument to include this capability, and validate the measurements, through comparison with ozone production from VOC oxidation in a large simulation chamber, and by measurement of the key oxidant OH radicals, and their precursors, within the system. We will then apply the instrument to compare the measured ozone production rates with those calculated using other observational and model approaches, and to characterise the ozone control regime, in two contrasting environments: In the outflow of a European megacity (at Weybourne Atmospheric Observatory, WAO, in the UK), and in a rural continental location (at Hohenpeissenberg, HPB, in southern Germany). At WAO, we will compare the measured ozone production rate with that calculated through co-located measurements of HO2 and RO2 radicals (using a newly developed approach to distinguish between these closely related species), and with that simulated using a constrained photochemical box model. We will compare the NOx-dependence of the ozone production rate with that predicted using indicator approaches, based upon observations of other chemical species. At HPB, we will focus upon the VOC-dependence of the ozone production rate, and assess the error in model predictions of ozone production, which arise from the presence of unmeasured VOCs.The project will develop and demonstrate a new measurement approach, and apply this to improve our understanding of a fundamental aspect of atmospheric chemical processing. Future applications have considerable potential both to support atmospheric science research, but also as an important air quality tool, alongside existing measurement and modelling approaches, to inform the most effective emission controls to reduce ozone production in a given location. In the context of global crop yield reductions arising from ozone exposure of 7 - 12 % (wheat), 6 - 16 % (soybean) and 3 - 4 % (rice), this is an important societal as well as scientific goal.

对流层臭氧是一种重要的空气污染物，对人类健康、农作物和植被都有危害。它是大气氧化剂的主要前体，大气氧化剂会使排放到大气中的大多数反应性气体降解，本身就是一种重要的温室气体。由于在大气化学和空气污染中的这一核心作用，了解、预测和管理对流层臭氧水平的能力是大气科学研究的一个关键目标。这一目标很难实现，因为臭氧是一种二次污染物，在氮氧化物和阳光的存在下，通过挥发性有机化合物的复杂氧化在大气中形成，并且臭氧产生的时间尺度使得原位化学过程、沉积和传输的组合控制臭氧水平。所有这些因素的不确定性会影响用于预测当前和未来臭氧水平的数值模型的准确性，从而阻碍制定最佳空气质量政策以减轻臭氧暴露。在这里，我们将通过测量当地的化学臭氧生产率来解决这个问题，并（首次）测量当地大气臭氧生产率对NOx和VOC水平的响应-直接确定臭氧生产机制。我们将通过建立现有的测量大气臭氧生成率的仪器来实现这一目标（通过NERC技术概念验证资助，并在最近的ClearfLo“伦敦清洁空气”NERC城市大气科学计划中部署）。除了直接测量臭氧产生之外，通过扰动环境化学条件（例如，通过将NOx或VOC添加到采样气流中），并测量这种变化对测量的臭氧产生速率的影响，可以直接确定臭氧控制方案（NOx对VOC限制的程度）。在这个项目中，我们将开发我们现有的臭氧生产仪器，包括这种能力，并通过与大型模拟室中VOC氧化的臭氧生产进行比较，并通过测量系统内的关键氧化剂OH自由基及其前体来验证测量结果。然后，我们将应用该仪器来比较测量的臭氧生产率与使用其他观测和模型方法计算的臭氧生产率，并在两个对比鲜明的环境中验证臭氧控制制度：在欧洲大城市的外流（在Weybourne大气观测站，WAO，在英国），并在农村大陆的位置（在Hohenpeissenberg，HPB，在德国南部）。在WAO，我们将比较测量的臭氧产生率与通过HO 2和RO 2自由基的同位测量计算的臭氧产生率（使用新开发的方法来区分这些密切相关的物种），以及使用约束光化学箱模型模拟的臭氧产生率。我们将比较氮氧化物依赖的臭氧生产率与预测使用指标的方法，根据其他化学物质的观察。在HPB，我们将专注于臭氧生成速率的VOC依赖性，并评估臭氧生成的模型预测中的误差，这是由于未测量的VOC的存在而引起的。该项目将开发和演示一种新的测量方法，并将其应用于提高我们对大气化学处理基本方面的理解。未来的应用不仅在支持大气科学研究方面具有相当大的潜力，而且还可以作为一种重要的空气质量工具，与现有的测量和建模方法一起，为最有效的排放控制提供信息，以减少特定地点的臭氧生成。在臭氧暴露导致全球作物产量减少7 - 12%（小麦），6 - 16%（大豆）和3 - 4%（水稻）的背景下，这是一个重要的社会和科学目标。

项目成果

Seasonal and geographical variability of nitryl chloride and its precursors in Northern Europe

• DOI: 10.1002/asl.844
• 发表时间: 2018-08
• 期刊: Atmospheric Science Letters
• 影响因子: 3
• 作者: R. Sommariva;L. Hollis;T. Sherwen;A. Baker;S. Ball;B. Bandy;T. Bell;M. N. Chowdhury;R. Cordell;M. J. Evans;James D. Lee;C. Reed;C. Reeves;J. Roberts;Mingxi Yang;P. Monks

Effects of halogens on European air-quality.

• DOI: 10.1039/c7fd00026j
• 发表时间: 2017-08
• 期刊: Faraday discussions
• 影响因子: 3.4
• 作者: T. Sherwen;M. Evans;R. Sommariva;L. Hollis;S. Ball;P. Monks;C. Reed;L. Carpenter;James D. Lee;G. Forster;B. Bandy;C. Reeves;W. Bloss