Assessing chemistry schemes and constraints in air quality models used to predict ozone in London against the detailed Master Chemical Mechanism.
Assessing chemistry schemes and constraints in air quality models used to predict ozone in London against the detailed Master Chemical Mechanism.
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根据详细的主化学机制评估用于预测伦敦臭氧的空气质量模型中的化学方案和限制。
DOI：
10.1039/c5fd00218d
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发表时间：
2016
影响因子：
3.4
通讯作者：
Malkin TL
中科院分区：
文献类型：
--
作者：
Malkin TL
空气污染是欧洲对人类健康影响最大的环境因素。了解在相关空间尺度上驱动空气质量的关键过程，特别是在污染超标和发作期间，对于为决策者和公众提供有效的预测至关重要。尤其重要的是，政策监管者要了解可以由国家政策调节的本地空气质量驱动因素，而不是来自欧洲大陆或其他地方的区域污染。城市和区域耦合过程：对空气质量的影响（CUREAIR）项目的主要目标之一是确定当地和区域对臭氧事件的贡献。使用主化学机制（MCMv3.2）运行的详细零维（0-D）盒模型作为基准模型，对通用反应集（GRS）和共同代表性中间体（CRIv2-R5）方案的不太明确的化学机制进行评估。大气弥散模拟系统（ADMS-Urban）和区域化学输运模式EMEP4UK分别使用GRS和CRI。MCM模型使用了一种近乎明确的挥发性有机化合物（VOCs）氧化的化学方案，并且受限于VOCs、NOx、CO、HONO（亚硝酸盐）、光解频率和ClearfLo（伦敦清洁空气）运动期间测量的气象参数的观测。研究了不太明确的化学方案对不同模式输入的敏感性：将GRS限制为ClearfLo期间观测到的总VOC，而不是ads - urban分散计算得出的VOC，包括排放和背景浓度，导致模拟臭氧显著增加（冬季增加674%）。将HONO化学纳入这一机制，特别是在其他自由基来源有限的冬季，导致预测的臭氧水平大幅增加（223%）。当GRS和CRIv2-R5方案在MCM的等效模式约束下运行时，它们能够在大多数时间内分别将近显式MCM预测的臭氧水平复制到40%和20%以内。这一趋势的一个例外是在夏季的污染事件中观察到的，当时反气旋条件有利于温度升高和臭氧浓度升高。MCM预测的原位O3在这些条件下受到生物源性VOCs的严重影响，低GRS [O3]: MCM [O3]比率（以及低CRIv2-R5 [O3]: MCM [O3]比率）表明，这些不太明确的方案不足以代表这些VOCs的全部O3生成潜力。为了充分评估本地排放产生的原位臭氧与伦敦逆风平流产生的臭氧的影响，必须确定自排放以来的时间（从而确定实际大气距离稳定状态有多远）。根据夏季在北肯辛顿观测到的NOx: NOy比值确定的平均传输时间的估计，以及MCM模型预测的在此之后的O3的比较，观测到的中位数[O3]的约60%可能来自当地排放。然而，在东风气流所经历的更温暖的条件下，观测到的[O3]可能受到伦敦排放的更大影响。
Air pollution is the environmental factor with the greatest impact on human health in Europe. Understanding the key processes driving air quality across the relevant spatial scales, especially during pollution exceedances and episodes, is essential to provide effective predictions for both policymakers and the public. It is particularly important for policy regulators to understand the drivers of local air quality that can be regulated by national policies versus the contribution from regional pollution transported from mainland Europe or elsewhere. One of the main objectives of the Coupled Urban and Regional processes: Effects on AIR quality (CUREAIR) project is to determine local and regional contributions to ozone events. A detailed zero-dimensional (0-D) box model run with the Master Chemical Mechanism (MCMv3.2) is used as the benchmark model against which the less explicit chemistry mechanisms of the Generic Reaction Set (GRS) and the Common Representative Intermediates (CRIv2-R5) schemes are evaluated. GRS and CRI are used by the Atmospheric Dispersion Modelling System (ADMS-Urban) and the regional chemistry transport model EMEP4UK, respectively. The MCM model uses a near-explicit chemical scheme for the oxidation of volatile organic compounds (VOCs) and is constrained to observations of VOCs, NOx, CO, HONO (nitrous acid), photolysis frequencies and meteorological parameters measured during the ClearfLo (Clean Air for London) campaign. The sensitivity of the less explicit chemistry schemes to different model inputs has been investigated: Constraining GRS to the total VOC observed during ClearfLo as opposed to VOC derived from ADMS-Urban dispersion calculations, including emissions and background concentrations, led to a significant increase (674% during winter) in modelled ozone. The inclusion of HONO chemistry in this mechanism, particularly during wintertime when other radical sources are limited, led to substantial increases in the ozone levels predicted (223%). When the GRS and CRIv2-R5 schemes are run with the equivalent model constraints to the MCM, they are able to reproduce the level of ozone predicted by the near-explicit MCM to within 40% and 20% respectively for the majority of the time. An exception to this trend was observed during pollution episodes experienced in the summer, when anticyclonic conditions favoured increased temperatures and elevated O3. The in situ O3 predicted by the MCM was heavily influenced by biogenic VOCs during these conditions and the low GRS [O3] : MCM [O3] ratio (and low CRIv2-R5 [O3] : MCM [O3] ratio) demonstrates that these less explicit schemes under-represent the full O3 creation potential of these VOCs. To fully assess the influence of the in situ O3 generated from local emissions versus O3 generated upwind of London and advected in, the time since emission (and, hence, how far the real atmosphere is from steady state) must be determined. From estimates of the mean transport time determined from the NOx : NOy ratio observed at North Kensington during the summer and comparison of the O3 predicted by the MCM model after this time, ∼60% of the median observed [O3] could be generated from local emissions. During the warmer conditions experienced during the easterly flows, however, the observed [O3] may be even more heavily influenced by London's emissions.
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DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
Peter Hurley
通讯作者：
Peter Hurley
影响因子：
6.3
作者：
Harrison, R. M.;Dall'Osto, M.;Smith, S.
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Smith, S.
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DOI：
--
发表时间：
1997
期刊：
影响因子：
--
作者：
J. Harris;S. Oltmans
通讯作者：
S. Oltmans
影响因子：
6.3
作者：
L. Whalley;D. Stone;B. Bandy;R. Dunmore;J. Hamilton;J. Hopkins;James D. Lee;A. Lewis;D. Heard
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L. Whalley;D. Stone;B. Bandy;R. Dunmore;J. Hamilton;J. Hopkins;James D. Lee;A. Lewis;D. Heard
英国韦伯恩大气观测站一年的 H2 测量
DOI：
--
发表时间：
2012
期刊：
影响因子：
--
作者：
G. Forster;W. Sturges;Z. Fleming;B. Bandy;Stefan Emeis
通讯作者：
Stefan Emeis