Need an intro?
This article is pretty detailed. If you want to read the basics first, take a look at MappAir 101. If you’re feeling brave, read on.
What is MappAir UK?
The UK national MappAir model is a first of its kind: a high resolution, source-apportioned hourly air quality model covering a whole nation. The data can be used to help estimate human exposure to poor air quality since the resolution is detailed enough to distinguish between locations near each other.
By providing real-time and forecasted air quality information, MappAir arms the user with actionable insights and a valuable mechanism to track locations without the need to perform individual modelling assessments.
Did you know? Air quality models have been used since the mid 20th century. One of the first air quality models was the Gaussian plume model, introduced in the 1950s. It was used to predict the dispersion of pollutants in the atmosphere from point sources like smokestacks. This model was based on the Gaussian distribution and provided a mathematical framework to estimate pollutant concentrations at various distances from the source.
What can it be used for?
The national model facilitates many use cases, with rapidly accessible information requiring no prior air quality knowledge or experience in modelling. Here are just a few examples:
- Hourly tracking lets you establishes a dataset at specific locations, highlighting historic trends and exceedances. Try using a virtual zephyr to start tracking a location.
- 48-hour forecasting enables early communication of pollution events to help protect environmentally sensitive individuals and help promote positive behaviour.
- Detailed source information provides insights into the causes of poor air quality, helping guide policy and drive positive behavioural change.
- High spatial resolution enables route analysis to support clean routing applications to arm your community with tools to lower their exposure.
How does it work?
Modelling large areas in real-time is very resource intensive and limits traditional modelling software. MappAir overcomes this using state-of-the-art computer science approaches to optimise performance and achieve compliant data quality.
Our specialist team has worked tirelessly to improve the emissions inventories, using spatial and temporal surrogates to meet the high-spatial resolution requirements that we set ourselves for MappAir. We are particularly proud of our residential wood combustion (RWC) emission inventories.
The built-in traffic model captures activity across the road-network, including minor roads and can be linked to live traffic data where available.
Gaussian plume dispersion principles are utilised to distribute emissions using high-resolution meteorological data.
The result is air quality data…
- Covering the entire UK in high resolution
- In real-time and up to 48-hour forecasts
- Produced on the hour, every hour
- Including specific detail on the dominant sources
What is Source Apportionment?
Many things affect air quality, and it is not always clear where attention should be focused to improve it. Understanding the key culprits is vital for effective policy and behavioural change strategies.
MappAir accounts for a wide range of source emissions, providing granular information to the user as a breakdown of emission sources, helping them make active decisions about which sources are most important to tackle.
Notably, MappAir considers regional pollution which can be transboundary. This is important, as not all pollution is generated locally and understanding this can help improve wider partnerships with neighbouring areas. Working together is pivotal and often creates the most effective impact.
Members of the public often have an active interest and want to know why air quality is poor in their area. By providing them with a breakdown of sources they understand their impacts better and can make positive changes in their own lifestyle and those around them.
Where does the data come from?
To facilitate the UK model, several third-party datasets are used.
Data Source | Purpose |
NAEI | National Atmospheric Emissions Inventory provides emissions data which EarthSense apply GIS techniques to improve the spatial resolution. Used for Non-Road Transport and Domestic wood burning |
ENSEMBLE (CAMS) | A long-range transport air quality model used for determining regional pollution |
Met-Office | High resolution metrology forecast system used for distributing emissions from source |
DfT | Site categorised road traffic data for road transport emissions |
AURN | Automated Urban and Rural Network, real-time air quality reference stations used for calibration and validation |
How accurate is it?
The NO₂ data quality meets the objectives of EU directive 2008.50.EC and is continuously evaluated to provide confidence in the outputs.
Understanding the uncertainty in data is important when deciding what uses it’s appropriate for. EU directive 2008.50.EC sets the hourly modelling data quality objective for the estimation of NO₂ at 50% error. We have used the same uncertainty value for PM₂.₅ in lieu of there being no objective specified for this pollutant.
In the UK, we use the AURN to calibrate the model and then validate the performance in a blind test. This repeated continuously to help improve calibrations.
We are also working on sensor kriging, a method that improves the model's data quality by adjusting to a network of quality assured Zephyrs. This will empower the model to respond to local pollution events not captured in the emission inventories.
Our modelling team produce a range of other performance statistics that can be more representative of real-world performance, such as RMSE.
Uncertainty (objective 50%) | RMSE | |
NO₂ | 6.24% | 8.35 |
PM₂.₅ | 4.48% | 5.5 |
How can I access the data?
MyAir is the best place to access the UK national model if your subscription allows. Here you can view regional air quality with customisable map overlays and choose locations to track and benefit from detailed inbuilt analysis features.
We also provide an API (application programming interface) for use cases which may benefit for incorporating reliable, high resolution air quality data. Speak to our sales team for advice on how we can add value to your application.