This Pump-Priming project will initiate a new collaboration with a leading Chinese research group led by Prof Pingqing Fu at Institute of Atmospheric Physics (IAP-CAS). Our aim is to provide definitive evidence, for the first time, on the formation of silicon-containing secondary organic aerosols (Si-SOAs) via photochemical atmospheric processing by using the novel techniques at the IAP-CAS and the UoB. The wider project context is the oxidation of Si-containing volatile organic compounds (Si-VOCs), which are widely used in personal care products and industrial applications. Si-VOCs are the most abundant VOCs in indoor air and its concentration in Chinese megacities can be over 10 microgram per cubic meter (which is extremely high). Si-VOCs can be oxidised by hydroxyl radicals and form secondary organic aerosols (SOAs), which contributes to the regional haze pollution. Our current NERC project Sources and Emissions of Air Pollutants in a Chinese Megacity - AIRPOLL-Beijing (NE/N007190/1) (2016 - 2020) integrates recent modelling, flux measurements, satellite retrievals, tower vertical profile measurements, and chemical transport modelling to provide thorough understanding of the sources and emissions of air pollutants in Beijing, at unprecedented detail and accuracy. As part of this project awarded to the University of Birmingham, we analyzed the chemical composition of individual particles collected during the winter campaign (Nov-Dec 2016) and found that >50% the fine particles contain silicon with mass fraction > 0.01. This suggests that silicon may play an important role in the formation of fine particles, which cause widespread smog / haze and lead to adverse human health effects. We also discovered that silicon is present as a coating, rather than as a solid grain, in individual sulphur-rich particles collected downwind of Chinese megacities, suggesting that the silicon is not directly emitted from primary sources (i.e., formed in the atmosphere). These new findings promoted us to hypothesize that silicon in the secondary particles in ambient air is formed from chemical processing of gas phase Si-containing VOCs. Si-SOA project will rigorously test this hypothesis. To do this, we will apply a series of novel techniques to study silicon in fine particles for the first time. We will use STEM (Scanning Transmission Electron Microscopy) and NanoSIMS (Nanoscale Secondary Ion Mass Spectrometer) to speciate silicon in atmospheric fine particles and confirm whether silicon in individual secondary particles is present as organosilicon. If confirmed, thiswill provide "smoking gun" on the formation of silicon organic aerosol by atmospheric processing. We will also apply the ESI-HRMS (Electrospray ionisation - high resolution mass spectrometer) to identify Si-containing organic molecules in fine particles and then gas chromatography - mass spectrometer to quantify the concentration of Si-SOAs identified by ESI-HRMS in selected fine particle samples collected during the APHH-China campaigns. Si-SOA project will add value to the AIRPOLL-Beijing by confirming the presence and quantify the concentration of siloxane oxidation products in fine particles. It will provide a better understanding on the sources of secondary organic aerosols, a key objective of AIRPOLL-Beijing. The project will consist of PI / research staff exchanges to plan and carry out the experiments in detail, followed by discussions on publication(s). This proposal has been developed following discussions between SHI and FU at meetings in Beijing in May 2017, which was initiated by discovery of silicon as coating in individual secondary sulphate-rich particles and the detection of silicon in over 50% of individual fine particles (see above). In addition to the specific science goals, Si-SOA will nurture a developing collaboration between UK groups and leading Chinese researchers at IAP, with potential for future links.

China is increasingly taking the lead in solutions to environmental problems and this will continue as substantial Chinese investment is scheduled for this purpose. The Institute of Atmospheric Physics (IAP) in Beijing is an internationally leading organisation in this area and will substantially benefit from this additional investment. The Applied Modelling and Computational Group at Imperial College London (AMCG-ICL) is an environmental modelling group developing next generation methods. We propose a two year starter project with a combination of training and scientific effort in the UK and China synchronized with a range of supporting activities that will build the foundation for a subsequently self supporting (combination of UK and Chinese funds) 'International Research Centre'. The Centre will combine our world leading technologies and manpower to accelerate research excellence and delivery of numerical modelling insights and solutions to grand challenge environmental problems in the UK and China way beyond the capability of the UK alone. A relatively small investment would leverage China's massive past, current and future investments in IAP and past UK investments in next generation environmental flow models (particularly the multi-scale ocean model Fluidity-ICOM). This collaboration will develop a world leading predictive modelling framework. The starter project funded here will provide the focus for the training and collaboration so as to apply IAP's data assimilation methods to our multi-scale ocean model Fluidity-ICOM. Next Generation Ocean-Atmosphere Model: A Grand Challenge in Earth System Science is modelling the global circulation across the full range of relevant spatial and temporal scales. For climate prediction, this means resolving both basin scale and smaller scale features such as boundary currents, mixing; chemical interactions and transport, overflows, and mesoscale eddies. Such simulations will lie well beyond the capability of traditional ocean and atmosphere models. It is now generally recognised that the next generation of ocean models will be based on unstructured mesh technology as currently this is the only feasible way of resolving the important range of scales in coastal regions. As identified by the NERC strategy document 'oceans 2025 WP9', unstructured mesh ocean models are the key ocean modelling technology for the future modelling of multi-scale ocean to estuary and smaller scale modelling. Among existing unstructured mesh models, ICOM-Fluidity is the only model that can be used for simulation of flow on all scales using adaptive mesh resolution and is therefore an ideal platform for the next generation of data assimilation models to be developed on. One result of the training program will be that ICOM-Fluidity will be used to form a forward model of the China Sea. There will be a large amount of data to assimilate into the model e.g. satellite, argo floats and ship tracks. Ensemble Kalman Filter EnKF and gradient or adjoint based data assimilation methods will be used with ICOM-Fluidity to provide forecasts and to interpolate available data. Planned activities that will support the IAP - AMCG-ICL research: 1) Training courses, workshops and Summer schools. 2) PhD students, PDRAs and senior staff time to apply (and help develop) the model e.g. set up the UK and China sea model and develop uncertainty, reduced order and data assimilation methods. 3) Exchanges of academic staff and PhD students. 4) Development of a new substantial funding grant in China and the UK to fund the centre. 5) Strengthened UK link and development of further initiatives with the Chinese Academy of Sciences. 6) Formalised visiting status for key Imperial College researchers

Air pollution is well established as having major negative impacts on human well-being, vegetation and general quality of life. Whilst the exact biological pathways and mechanisms for health impacts remain to be established, there is ample evidence to demonstrate that months to many years of life expectancy can be lost through exposure to air pollution outside. Those negative impacts are currently disproportionately experienced by those in living the world's largest cities and in rapidly developing economies. The basic causes of air pollution are understood; the combustion of fossil fuels for electricity, transport, cooking and heating, emissions from agriculture, from resource extraction, dust and so on, all play a part. Over the past two centuries economic expansion has always been closely tied to transition periods of increased air pollution and negative social and health outcomes. A key global challenge for the 21st century is to create a framework - scientific, regulatory, and technological - which enables economic development, with increases in individual prosperity and quality of life, without damaging air pollution as a side effect. Many of the processes associated with air pollution are non-linear in nature however, and the extremely complex composition of air, as both gases and particles, can make it very difficult to establish direct cause-and-effect. Pollutants often interact with one another in unexpected ways that can create negative unintended consequences from superficially reasonable policy interventions. This is a key area where scientific understanding remains incomplete. The inability to fully describe the chemistry and physics of the urban atmosphere limits society's ability to create effective solutions that work, and that do not conflict with wider developmental and economic goals. This project tackles some of the key uncertainties that remain in urban air processes, including how polluting chemicals are transformed or oxidised in the atmosphere, how gases and particles interact, how pollution is dispersed by weather, how remote emissions from outside the city impacts on urban populations and how the presence of pollution itself may affect feedback and alter on meteorology in cities. The project focuses its study on three key types of harmful air pollution: particulate matter (referred to as PM), nitrogen dioxide (NO2), and ozone O3. The project is a collaboration between ten UK Universities, three leading Chinese research institutes, all part of the Chinese Academy of Sciences, Peking University and three UK partner research organisations (CERC, NPL, Met Office). The project centre-piece are two periods of intensive observations in the centre of Beijing, in the contrasting atmospheric conditions of winter and summer. The experiments will make measurements at the surface, and in the vertical using a unique 1000ft meteorological tower. These experiments will generate a complex and multiparameter dataset that can challenge state of the art computer models of urban pollution. By challenging models with detailed data, their capabilities can be assessed and their weaknesses and failings identified, and then targeted for improvement. This is vital since the pathway to achieving better air quality is through policy that is underpinned by scientific understanding, and in air pollution science, that understanding is encapsulated in these computer models. The project will use state of the art models from the UK and from China, and develop methods to generate very high spatial resolution estimates of pollution at the surface, a type of data that is essential when studying the health effects of pollution, or evaluating how successful a future policy might be.

Globally averaged surface air temperature (SAT) during the 20th and 21st centuries displays a gradual warming and superimposed year-to-year and decadal-scale fluctuations. The upward trend contains the climate response to an anthropogenic increase of heat-trapping atmospheric greenhouse gases. The temperature ups and downs around the trend - that are particularly pronounced in the Arctic - mostly reflect natural variability. Natural climate variations are of two types, internal and external. The former is produced by the climate system itself, e.g. due to variations in ocean circulation. An example of the latter is solar-induced climate variability. Decadal-scale variability is of large societal relevance. It is observed, for example, in Atlantic hurricane activity, Sahel rainfall, Indian and East Asian Monsoons, Eurasian winter coldness and in the Arctic SAT and sea ice. The understanding and skillful prediction of decadal-scale climate variability that modulates the regional occurrence of extreme weather events will be of enormous societal and economic benefit. InterDec is an international initiative aiming at understanding the origin of decadal-scale climate variability in different regions of the world and the linkages between them by using observational data sets and through coordinated multi-model experiments. How can a decadal-scale climate anomaly in one region influence very distant areas of the planet? This can happen through atmospheric or oceanic teleconnections. Fast signal communication between different latitudinal belts within days or weeks is possible through atmospheric teleconnection, whereas communication through oceanic pathways is much slower requiring years to decades or even longer. Understanding these processes will enhance decadal climate prediction of both mean climate variations and associated trends in regional extreme events. Scientists from different European countries, from China and Japan will closely collaborate to disentangle the secrets of the inter-relations of decadal-scale variability around the globe.

Beijing suffers from very high concentrations of airborne pollutants, leading to adverse health and wellbeing for over twenty million people. The pollutants likely to have the greatest effects upon human health are particulate matter, nitrogen dioxide and ozone. Both particulate matter and nitrogen dioxide are emitted directly from individual sources (primary contributions, many of which are not well quantified); and are formed in the atmosphere (secondary contributions, which are highly complex). Ozone is entirely secondary in nature, formed from reactions of precursor gases, whose sources and abundance are also challenging to constrain. These uncertainties hinder understanding of the causes of air pollution in Beijing, which is needed to deliver effective and efficient strategies for pollution reduction and health improvement. AIRPOLL-Beijing project will address this challenge, through identification and quantification of the sources and emissions of air pollutants in Beijing. The project sits within the NERC/MRC-NSFC China megacity programme, which includes projects addressing the atmospheric processes affecting air pollutants, human exposure and health effects, and solutions / mitigation strategies to reduce air pollution and health impacts. The project exploits the combined experience and expertise of leading UK and Chinese scientists, applying multiple complementary approaches. The project deploys multiple atmospheric measurement and analysis strategies to characterise pollutant abundance and sources, develop novel emissions inventories, and integrate these to produce new modelling tools for use in policy development. We adopt a range of state-of-the-science approaches: -Receptor Modelling, where detailed composition measurements are used to infer pollutant sources from their chemical signatures, combining world-leading UK and Chinese capability. -Flux Measurements, where the total release of pollutants from all sources is measured, providing a key metric to refine emission inventories. We will combine near-ground measurements (using the unique Institute of Atmospheric Physics 325m tower in central Beijing), ground-based observations and fluxes derived from satellite observations. -3D spatial analysis, in which a novel sensor network will be deployed around central Beijing to measure pollutant fields. -Development of novel emissions inventories, which will predict the temporally- and spatially- resolved emissions of air pollutants from all sources, enhancing existing capability. -Development of new online modelling tools, within which to integrate emissions, atmospheric processing and meteorology to predict primary and secondary pollutant concentration fields. AIRPOLL-Beijing will integrate these approaches to provide thorough understanding of the sources and emissions of air pollutants in Beijing, at unprecedented detail and accuracy. While the project is a self-contained activity, key deliverables feed into Processes, Health and Solutions themes of the programme. This proposal seeks Newton fund support, part of the UK's Official Development Assistance (ODA) commitment. The project will directly address ODA objectives, in the categories of (i) people (through the joint development of novel scientific approaches to the understanding of megacity air pollution), (ii) programmes (as all aspects of the project are joint UK-Chinese research endeavours) and (iii) translation (through provision of detailed air pollution source assessments, in support of assessment of health impacts and development of mitigation strategies). More generally, the project will leave a legacy of improved air pollution understanding and research capacity of the Chinese teams, and, through integration with other themes of the Megacities programme, underpin improvements in the health and welfare of the population of Beijing, and across China more widely - ultimately benefitting more than a billion people.