Climate and Air Quality Impact of Airborne Halogens

空气中卤素对气候和空气质量的影响

• 批准号: NE/N014375/1
• 负责人: Ryan Hossaini
• 金额: $ 60.15万
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FN014375%2F1
• 关键词: Climate; Air; Quality; Impact; Airborne

Bromine, chlorine & iodine (halogens) are chemical elements which play a fundamental role in Earth's atmosphere and are implicated in a range of environmental issues. Since the 1970s, scientists have known that halogens (mostly chlorine) damage the ozone layer in Earth's stratosphere (located between 11 & 50 km above the surface) and are responsible for the infamous Antarctic 'Ozone Hole', first observed in the 1980s. As ozone shields Earth's surface from harmful solar radiation, production of many halogen compounds is prohibited under international law. However, it is now increasingly recognised that halogens also exert a large influence on the lowest region of Earth's atmosphere (the troposphere) in ways important for both climate and air quality. Only recently have field measurements revealed that halogens are virtually ubiquitous throughout the troposphere, though there is much debate as to their source. Unlike the stratosphere, we think most tropospheric halogens come from the biosphere (e.g. the ocean) and other natural sources (e.g. sea-ice, volcanoes), though these sources are poorly characterised. In addition, human activities related to the rapidly growing aquaculture sector (e.g. commercial seaweed farms) and other industries are increasing the amount of halogens entering the troposphere.Why is this important? Halogens do a number of things, but fundamentally they alter the troposphere's "oxidising power"; that is, its ability to "self-cleanse" and rid itself of various chemical compounds. From a climate perspective, this has important implications; it means halogens may (i) alter the length of time greenhouse gases, such as methane, remain in the atmosphere and thus influence their global warming potential and (ii) alter the production rate of aerosol (microscopic particles suspended in the atmosphere) which alter cloud properties and cool Earth's climate. What's more, halogens degrade air quality by promoting surface ozone formation. At ground-level, ozone is a pollutant (& greenhouse gas) and prolonged exposure can lead to respiratory ailments, including asthma, and is damaging to crops. Nitryl chloride, a halogen-containing precursor to adverse air quality events, has been detected in large quantities in coastal and inland regions of the USA. Elevated levels of this compound have also recently been detected in Germany, though no study has comprehensively examined the role of halogens in air pollution over Europe. As an island nation in the vicinity to significant quantities of sea salt (a major halogen source), UK air quality could be particularly susceptible to being compromised by halogens. Ultimately, despite the leverage halogens possess to impact both climate & air quality, they have yet to be considered in most computer model simulations used to study and forecast these phenomena. This Fellowship addresses that omission, seeking to unravel the wider impact that airborne halogens have on our environment.I will develop the first fully integrated computer model of the biosphere-halogen-climate system which can (i) characterise and quantify tropospheric halogen sources, (ii) determine the atmospheric fate of these gases and (iii) quantify their impacts, on regional to global scales. A key question to tackle is; in the troposphere, how have halogen levels, processes and impacts changed over time? This holistic modelling approach, which accounts for changes to halogen emissions from the biosphere due to evolving environmental factors (e.g. sea surface temperature & sea-ice cover), will provide the answer. Critically, this will enable climate-induced feedbacks on halogen emissions, which could diminish or amplify future climate change, to be assessed for the first time, leading to climate simulations of greater fidelity. This research provides powerful new insight into poorly understood, yet fundamental processes important for both climate change and air quality - pressing environmental concerns of today.

溴、氯和碘（卤素）是在地球大气中发挥重要作用的化学元素，与一系列环境问题有关。自20世纪70年代以来，科学家们已经知道卤素（主要是氯）会破坏地球平流层（位于地表以上11 - 50公里处）的臭氧层，并对20世纪80年代首次观察到的臭名昭著的南极“臭氧洞”负责。由于臭氧保护地球表面免受有害的太阳辐射，因此国际法禁止生产许多卤素化合物。然而，现在人们越来越认识到，卤素也对地球大气层的最低区域（对流层）产生重大影响，对气候和空气质量都很重要。直到最近，实地测量才揭示出卤素在整个对流层中几乎无处不在，尽管关于它们的来源有很多争论。与平流层不同，我们认为大多数对流层卤素来自生物圈（例如海洋）和其他自然来源（例如海冰，火山），尽管这些来源的特征很差。此外，与快速增长的水产养殖业（例如商业海藻养殖场）和其他行业相关的人类活动正在增加进入对流层的卤素数量。卤素有很多作用，但从根本上说，它们改变了对流层的“氧化能力”，也就是说，它的“自我清洁”能力，以及清除各种化合物的能力。从气候的角度来看，这具有重要的影响;这意味着卤素可能（i）改变温室气体（如甲烷）在大气中停留的时间长度，从而影响其全球变暖潜力，（ii）改变气溶胶（悬浮在大气中的微观颗粒）的产生速率，从而改变云的特性并冷却地球气候。更重要的是，卤素通过促进表面臭氧的形成来降低空气质量。在地面上，臭氧是一种污染物（温室气体），长期接触会导致呼吸系统疾病，包括哮喘，并对农作物造成损害。硝酰氯是一种含卤素的有害空气质量事件的前体，在美国的沿海和内陆地区被大量检测到。最近在德国也检测到这种化合物的水平升高，尽管没有研究全面研究卤素在欧洲空气污染中的作用。作为一个邻近大量海盐（一种主要的卤素来源）的岛国，英国的空气质量特别容易受到卤素的影响。最终，尽管卤素具有影响气候和空气质量的杠杆作用，但它们尚未在用于研究和预测这些现象的大多数计算机模型模拟中得到考虑。这个奖学金地址的遗漏，寻求解开更广泛的影响，空气中的卤素对我们的environment.I将开发的生物圈卤素气候系统的第一个完全集成的计算机模型，可以（一）确定和量化对流层卤素源，（二）确定这些气体的大气命运和（三）量化其影响，在区域到全球范围内。需要解决的一个关键问题是：在对流层中，卤素水平、过程和影响如何随时间变化？这一整体建模方法将提供答案，该方法解释了由于不断变化的环境因素（例如海面温度和海冰覆盖）而导致的生物圈卤素排放的变化。至关重要的是，这将首次评估气候引起的卤素排放反馈，这可能会减少或扩大未来的气候变化，从而提高气候模拟的逼真度。这项研究提供了强有力的新见解，了解很少，但对气候变化和空气质量都很重要的基本过程-今天紧迫的环境问题。

项目成果

Rapid increase in dichloromethane emissions from China inferred through atmospheric observations.

• DOI: 10.1038/s41467-021-27592-y
• 发表时间: 2021-12-14
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: An M;Western LM;Say D;Chen L;Claxton T;Ganesan AL;Hossaini R;Krummel PB;Manning AJ;Mühle J;O'Doherty S;Prinn RG;Weiss RF;Young D;Hu J;Yao B;Rigby M
• 通讯作者: Rigby M

Description and evaluation of the new UM-UKCA (vn11.0) Double Extended Stratospheric-Tropospheric (DEST vn1.0) scheme for comprehensive modelling of halogen chemistry in the stratosphere

用于平流层卤素化学综合建模的新 UM-UKCA (vn11.0) 双扩展平流层-对流层 (DEST vn1.0) 方案的描述和评估

• DOI: 10.5194/gmd-2022-215
• 发表时间: 2022
• 作者: Bednarz E

On the Cause of Recent Variations in Lower Stratospheric Ozone

• DOI: 10.1029/2018gl078071
• 发表时间: 2018-06
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: M. Chipperfield;S. Dhomse;R. Hossaini;W. Feng;M. Santee;M. Weber;J. Burrows;J. Wild;D. Loyola-D.-Lo

Atmospheric impacts of chlorinated very short-lived substances over the recent past - Part 2: Impacts on ozone

近期氯化极短寿命物质对大气的影响 - 第 2 部分：对臭氧的影响

• DOI: 10.5194/egusphere-2023-496
• 发表时间: 2023
• 作者: Bednarz E