3 Feb 2022Defra 2021 Air Quality Model Intercomparison Exercise

CERC are undertaking a project commissioned by Defra in partnership with the Met Office, the UK Centre for Ecology and Hydrology (UKCEH), the Environmental Research Group at Imperial College London and Ricardo in relation to an intercomparison study between models that have the potential to be used for Defra's compliance reporting commitments. Models involved in the intercomparison exercise are: the air quality model included in the Met Office's Unified Model (AQUM), UKCEH's application of the European Monitoring and Evaluation Programme EMEP MSC-W model, Imperial College's CMAQ-Urban model, in addition to Ricardo's Pollution Climate Mapping model, which is currently used for reporting in relation to the UK's EU Directive (2008/50/EC) requirements.

All models have been configured to calculate pollutant concentrations over the whole of the UK, for 2018, at a sufficiently high resolution to allow quantification of air quality at background and, where possible, roadside locations. CERC's role has been to undertake the model evaluation, and over the last year, the team has been working closely with all modelling teams to facilitate the provision of the data required for the study.

CERC have assessed the formulations of the meteorological, chemistry and pollutant dispersion components of the modelling systems, including quantification of some model inputs and outputs. Facilitated by the powerful MAQS-Health Verification System, modelled concentrations have been evaluated in comparison with measured data from over 400 monitors from multiple networks, including a wide range of short- and long-term metrics. The metrics associated with Air Quality Directive reporting were derived from each model dataset and compared in graphical and statistical format. Common themes were identified including data quality and availability, calibration approaches and potential for future development. The final project report is currently under review by Defra and will inform Defra's modelling strategy for the future.

26 Jan 2022CERC assesses Low Traffic Neighbourhoods in Lambeth and Southwark

As part of an emergency transport response to the pandemic, Low Traffic Neighbourhoods (LTNs) have been introduced in many London Boroughs, to help people safely walk, cycle and use public transport.

CERC consultants have been evaluating the air quality impact of LTN schemes, including five schemes in Lambeth and the Walworth and Dulwich schemes in Southwark. Using local traffic monitoring data as input, the modelling assessments consider pre-scheme and post-scheme scenarios to assess the air quality impact of these LTNs.

CERC's ADMS-Urban and emissions inventory tool EMIT were used for the modelling. In addition to local traffic data, the model set-up used data from the London Atmospheric Emissions Inventory.

Concentrations of NO₂, PM₁₀ and PM_2.5 were modelled on a grid of receptor points within each LTN, to generate high resolution maps for the scheme areas. Model output was also generated at sensitive receptors, such as schools and hospitals.

LTN monitoring reports for Lambeth can be viewed on the Council website.Where LTNs are finalised, CERC reports are available to view, for example for the Railton LTN. The figure shows the change in annual average NO₂ concentrations at Railton LTN, assessed using significance criteria from EPUK and IAQM guidance for Land Use Planning & Development Control.

A presentation on the assessment of LTNs from the 2021 ADMS User Group Meeting is available to view on the CERC website user area.

4 Jan 20222021 ADMS User Group Meetings - recordings of CERC presentations are available to view

Following last year's ADMS User Group Meetings, which took place online on 24 and 25 November, recordings of the CERC presentations are now available to view in the CERC website User Area, alongside these are PDF copies of all the presentations. Model users with a valid support contract, including all annual licence holders, are entitled to register for password-protected access to the User Area. To register, or to be reminded of your password, click here.

8 Nov 2021COP26: Verifying Glasgow's CO2 emissions using ADMS-Urban and measurements

Verification of carbon dioxide emissions is essential to achieving Net Zero and "keeping 1.5 alive". Researchers from CERC, Cambridge University, and ACOEM have collaborated on a project to verify CO₂ emissions across greater Glasgow by combining measurements and CERC's ADMS-Urban air pollution dispersion model. These methods could be applied to verify the effectiveness of Net Zero policies for other cities.

From June 2021, fifteen AQMesh pods taking measurements of CO₂ and other pollutants at 1-minute resolution have been co-located with Scottish Air Quality Network reference monitors at sites in Glasgow City, West Dunbartonshire, Renfrewshire and South Lanarkshire. From September 2021, two LI-COR reference-grade instruments have also been measuring CO₂ at 1-minute resolution at two sites. ADMS-Urban has been applied to calculate hourly CO₂ concentrations at the measurement sites for the period of the measurements using NAEI gridded emissions and DfT traffic flows, and allowing for the effects of street canyons. Road emissions within 2km of each monitoring site have been modelled explicitly as road sources; other road emissions have been modelled as 1kmx1km gridded emissions. Hourly background CO₂ has been calculated from hourly baselines of the 1-minute AQMesh measurements calculated by the University of Cambridge team.

CERC researchers have applied Bayesian based inversion techniques to combine hourly modelled CO₂ concentrations from ADMS-Urban with hourly averaged AQMesh and LI-COR CO₂ measurements (top figure). The technique allows for the differences in uncertainties between low-cost sensors and reference monitors, for the uncertainties of the emissions from each source and for correlations between source emissions. The differences between the original and inversion-verified emissions (bottom figure) provide an indication of the accuracy of the original emissions inventory.

The project is funded by NERC and the Scottish Government.

12 Oct 2021CERC present at AQE Show and UKHSA Annual Review Meeting

This is a very busy time for CERC, presenting our research results to a wide range of audiences at key events this week.

The Air Quality and Emissions Virtual Event 2021 is being held on the 13^th and 14^th October. Speakers from government, academia and industry are presenting on a range of topics including national air quality monitoring and indoor air quality. Amy Stidworthy is presenting results from the application of CERC's Bayesian-based inversion methodology, which has been used to quantify the impact of COVID-19 restrictions on emissions in London by combining modelling and measurements. Read the abstract to Amy's talk and register for the free event.

The 2021 UK Health Security Agency (UKHSA) Annual UK Review Meeting on Outdoor and Indoor Air Pollution Research is being held online on the 14^th October. This key national meeting of the UK’s experts in the field of air pollution and health research is aimed at academics, policy makers, directors of public health and health charities; topics covered include air pollutant exposure and the impact of using green cleaning products on indoor air quality. Dr Jenny Stocker is giving an overview of the development of MAQS-Health, CERC's world-leading coupled air quality modelling system that spans national to urban street scales and accounts for physical and chemical processes at all relevant temporal and spatial scales. MAQS-Health is being developed to facilitate the generation of outdoor air pollutant concentration datasets suitable for health research as part of the SPF Clean Air Programme. Read the abstract to Jenny's talk and sign up for the meeting by Tuesday 12^th October.