Monitor for AeRosols and GAses - Fluxes of Inorganic and Organic compounds (MARGA-FIO)

Quantifying reactive gas and aerosol fluxes is vital to improve fundamental understanding of the Earth-System under multiple biogeochemical changes. To establish the next generation of models, it is necessary that we understand the interactions between chemical species. Emerging technology now provides the means to achieve this by building the first MARGA-FIO system.

MARGA-FIO stands for "Monitor for AeRosols and GAses - Fluxes of Inorganic and Organic compounds". This new facility will integrate a two-channel two-column on-line ion chromatography system built around a recently launched instrument (2060 MARGA). The facility will be globally unique in incorporating two sampling channels and two environmental enclosures, to sample at two different heights, allowing flux determination of water soluble inorganic and organic atmospheric constituents.

In flux-mode, MARGA-FIO will provide high resolution (hourly) concentration profiles so that the emission into the atmosphere or deposition to the surface can be measured. The trace gases measured cover ammonia (NH3), hydrochloric acid (HCl), nitric acid (HNO3), nitrous acid (HONO), sulphur dioxide (SO2), and the aerosol species ammonium (NH4+), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), nitrate (NO3-) and sulphate (SO42-). The instrument will also have the capability to quantify fluxes of amines and organic acids (e.g. dicarboxylic acids), which will be a world first.

In PM-mode, MARGA-FIO will measure online PM chemical composition at different size cut-offs (PM1, PM2.5 and PM10), in addition to the gas phase. This capability is unique as MARGA-FIO could chemically resolve >80% of the atmosphere-ecosystem exchange of PM and trace gases.

Three examples of unique applications of the MARGA-FIO are:

i) High resolution emission and deposition rates or "fluxes" of NH3 and HNO3, NH4+, NO3-, amines. This is important because nitrogen (N) pollution originating from agriculture (NH3) and transport/industry (nitrogen dioxide, NO2, HNO3) leads to complex atmospheric pollution impacting human health and damaging natural ecosystems. A low detection limit of MARGA-FIO will enable the study of pollutant deposition to our protected ecosystems. By measuring a range of key N compounds, the instrument will provide a holistic picture of the atmospheric impact of agriculture, transport and industry and detect where measures aimed at reducing the emission of one compound interacts with another (pollutant-swapping or co-benefits).

ii) Fluxes of HCl and Cl : In recent studies of the NERC Air Pollution and Human Health research programmes in China and India, it became apparent that there is a gap in flux measurement capability for halogen species, particularly HCl and Cl- , both by UK and international research groups. High concentrations of chloride pollution are observed in Beijing and Delhi, which are associated to waste combustion processes. However, the sources and atmospheric pathways are poorly understood. MARGA-FIO would be the first instrument in the UK atmospheric research community which can quantify the fluxes of these important pollutants. It can also resolve concentration and fluxes of base cation (sodium, potassium, magnesium, calcium) which form part of the dust that troubles ODA countries (e.g. India, East Africa).

iii) Organic pollutant fluxes: One of missing components in our understanding of the atmosphere is the rate of emission and deposition of organic PM constituents and gases, such as dicarboxylic acids. MARGA-FIO would offer a global step-change in quantitative measurement of previously un-measured processes at the surface-atmosphere interface. The data would complement existing capability with on-line Aerosol Mass Spectrometry available in the UK community, delivering much needed concentrations and emission rates / deposition velocities for constraining air quality and climate models.

MARGA-FIO delivers 26 inorganic and up to ~40 organic atmospheric measurements hourly. Flux data on this scale is transformational for understanding emissions/deposition pathways. The measurements of air-surface exchange and gas-particle partitioning will radically improve the understanding of pollutant deposition and chemistry and feed into the improvement of policy models. The MARGA-FIO data will support the UK and global communities in evidence for the UN Sustainable Development Goals, especially for clean air (linking SDGs 3, 7, 9, 11, 12, 13, 15). This underpins the NERC science strategy of managing environmental change and resilience to environmental hazards.

All MARGA-FIO outputs will be tracked on ResearchFish and data made freely available through BADC or EIDC and their metadata catalogues. Datasets will be promoted publically through data journal publications, presentations, social media. The unique name (MARGA-FIO) will help identify all outputs.

MARGA-FIO data and scientific interpretation will deliver quantitative evidence of air pollutant emissions and impacts. They will help improve emission inventories and model parameterisations, embedded in environmental models. This will build confidence for societal interventions and strategies for improvements embedded under UK's 25 year Environment Plan, and improve planning tools used at all levels in society. In this way they will contribute to more cost-effective environmental solutions, in both UK and ODA contexts. The core societal benefits are:

i) protecting the Nation's health from air pollution by quantifying the emission rates and chemical composition of particulate matter and trace gases, as a foundation for smart mitigation strategies
ii) protecting the environment by quantifying the nitrogen and other pollutant deposition to sensitive ecosystems, incl. providing a foundation for identifying synergies and trade-offs in agricultural mitigation and adaptation options.

In the coming decade there will need to be a paradigm shift from simple molecule processes such as NO2 emission and nitric acid deposition, from "organic" deposition, and single directional uptake onto PM to complex multi-species, multi-phase, multi-directional chemistry. Data from the MARGA-FIO will underpin this transformation allowing scientists to provide policy makers and the public with a more coherent understanding of the multiple consequences of human activities.

Atmospheric chemists - The system will provide high-resolution measurement evidence to validate theories related to expected flux processes, to help generate new theories, and quantitative data to parametrize thermodynamic and kinetic models of atmospheric chemistry.

Air quality, climate & ecosystem modellers - Using both the new data for validation and the new processes derived by atmospheric chemists, models will be improved to better understand, for example:

a. Nitrogen deposition over semi-natural ecosystems, which can be used to evaluate modelled critical loads to sensitive ecosystems and pollution pathways in the nitrogen and carbon cycles;
b. Particulate Matter composition to evaluate chemical transport models used in forecasting air quality in the UK and understand human health impact drivers;
c. Emission factors over megacities, including for particular source-apportionment related to water-soluble organic aerosols and chlorides.

Agencies & policy makers - The facility will support those responsible for developing the mitigation measures for air quality, especially PM and NH3. The Global Burden of Disease estimates that globally that poor air quality accounts for the premature deaths of 5.5 million people globally and flux measurements are vital to inform future interventions. The outcomes will feed into UK and international partnerships, including the UNECE Convention on Long-Range Transboundary Pollution, UNEP and the WMO Global Atmospheric Watch.