This document discusses using mesoscale models to forecast air quality in cities. It describes a modeling system that combines regional, national scale models with local scale city models. The system provides 72-hour air quality forecasts for cities. It is being applied in collaboration with local authorities in cities like Bristol and Manchester to provide spatial air quality data and forecasts to support public health, transportation, and environmental management. The collaboration aims to maximize the usefulness of regional air quality modeling for local decision-making.

1. University of Hertfordshire
Centre for Atmospheric & Instrumentation Research
Using Mesoscale Models to Forecast Air Quality in Cities
Dr Aidan Farrow a.farrow2@herts.ac.uk

2. Thanks to:
Dr Vikas Singh, Dr Charles Chemel, Prof Ranjeet Sokhi
NERC (HiRAE), NCAS (Air Quality Forecast) and Defra
Bristol City Council
TfGM, Salford and Oldham Councils
FP7 Transphorm Dr Aidan Farrow a.farrow2@herts.ac.uk

3. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Overview
• Mesoscale Models – Regional to National Scale
E.g. The NCAS-UH Air Quality Forecast
• Regional scale signals contribute at the City scale
• Coupling Regional to Local models
E.g. The HiRAE Project
• Application of Regional-Local Forecasts
E.g. Working with Local Authorities
Using Mesoscale Models to Forecast Air Quality in Cities

4. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Resolution:
Europe (50 km)
UK (10 km)
Vertical levels:
24 levels
A Mesoscale modeling system:

5. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Resolution:
Europe (50 km)
UK (10 km)
Vertical levels:
24 levels
A Mesoscale modeling system:

6. A 72 Hour ahead Air Quality forecast
WRF: Weather Research and Forecasting Model
SMOKE: The Sparse Matrix Operator Kernel
Emissions Modelling System
MEGAN: The Model of Emissions of
Gases and Aerosols from Nature
CMAQ: The Community Multi-scale
Air Quality CMAQ modelling system
Dr Aidan R Farrow a.farrow2@Herts.ac.uk
WRF
Numerical weather
prediction model
CMAQ
Chemical transport model
A Mesoscale modeling system:

7. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
European TNO emissions (2005)
Ten SNAP (Selected Nomenclature for Air Pollution) source
sectors and international shipping
SNAP Sectors
 Combustion in energy and transformation industries
 Non-industrial combustion plants
 Combustion in manufacturing industry
 Production processes
 Extraction and distribution of fossil fuels and geothermal energy
 Solvents and other product use
 Road transport
 Other mobile sources and machinery
 Waste treatment and disposal
 Agriculture
A Mesoscale modeling system:

8. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
A Mesoscale modeling system:
The NCAS Air Quality Forecast (AQF) system designed for the research community but is available publicly for all to view. The UK's official air quality forecast
system operated by DEFRA for public information can be found at http://uk-air.defra.gov.uk/forecasting/.

9. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
A Mesoscale modeling system:

10. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
The NCAS Air Quality Forecast (AQF) system designed for the research
community but is available publicly for all to view. The UK's official air quality
forecast system operated by DEFRA for public information can be found at
http://uk-air.defra.gov.uk/forecasting/.

11. Hourly PM2.5
Predictions for day
0-3 compare
favourably with
Urban and Rural
sites
Rural
Urban
Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Background
Forecast comparison with AURN measurements
(01-Jan-2014 to 30-June-2014)

12. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
PM2.5 comparison statistics
Statistics calculated at 40 PM2.5 background sites
Forecast performance indexes
• Correlation Coefficient (CORR)
• Mean error (MERR)
• Root mean square error (RMSE)

13. HiRAE - High Resolution Air-Quality and Exposure
1. Developed from the NCAS Air Quality Forecast
2. An ‘Innovation Project’ with City Authorities
3. To promote the use of Forecasting and Modelling technology
4. HiRAE is
1. A Co-Designed Project
2. Delivering NCAS Forecast Data
3. Developing new model products
4. Facilitating data exchange and expertise
Application of the Mesoscale system
Dr Aidan R Farrow a.farrow2@Herts.ac.uk

14. • Air Quality Impacts in the UK are substantial
• Health impacts cost UK £16bn annually (Defra)
• A factor in 29,000 deaths annually (HoC EAC 2014)
• City Authorities
• Responsible for managing Air Quality
• Responsible for meeting EU Air Quality Limit
Values
• Limited resources
• (e.g. Bristol 7 monitoring sites – no modelling ability)
• They are steering the project to maximize
benefit.
Local Authorities
Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Application of the Mesoscale system

15. Bristol
• City Authority
• 1 Million People in the urban area
• England’s 6th largest City
Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Greater Manchester
• TfGM and Councils
• 2.5 Million People
• Estimated 1300 deaths /140,000 adult
years of life lost
Application of the Mesoscale system
• How can the UH-NCAS forecast provide
maximum usefulness for Local Authorities?
• Prediction/Warning
• NO2 and PM
• Education
• Understanding Complex System
• Provide spatial data
• We are providing high resolution simulations of
air pollution for cities
1) City Air Quality maps
2) Forecast dashboard
1) Data download
2) Data visualization
3) Low exposure routes
4) Public Outreach and Active Travel
5) Transport Planning and Management

16. 16Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Local AQ, Sources,
Hotspots (e.g. PM, NOx)
Regional
AQ/climate,
LRT,
O3 and PM2.5
Urban AQ,
Photochemical
smog
NOx, Ozone, PM
Source
apportionment
LOCAL
URBAN
REGIONAL
GLOBAL
UK-City Forecast System
• What are the city vs regional processes the model needs to consider?
• Meteorology
• Localised sources and dispersion
• What does the system need to include?
• Regional Signal
• Local emissions
• Local dispersion

17. A 72 Hour ahead Air Quality forecast
WRF: Weather Research and Forecasting Model
SMOKE: The Sparse Matrix Operator Kernel
Emissions Modelling System
MEGAN: The Model of Emissions of
Gases and Aerosols from Nature
CMAQ: The Community Multi-scale
Air Quality CMAQ modelling system
Dr Aidan R Farrow a.farrow2@Herts.ac.uk
WRF
Numerical weather
prediction model
CMAQ
Chemical transport model

18. WRF
Numerical weather
prediction model
CMAQ
Chemical transport model
Air Quality Data Pre-
processor
Met Data Pre-processor
Emissions Data Pre-
processor
CAR-FMI
City Scale Model
Run Daily:
Europe - 50km
UK -10km
City traffic model
Bristol, Manchester, London

19. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Bloomsbury Measurement
Combined Urban and Regional
Model Signal
NO2 (µg/m3)

20. Dr Aidan R Farrow a.farrow2@Herts.ac.uk

21. Dr Aidan R Farrow a.farrow2@Herts.ac.uk

22. 22
Main Output
Products
Description
Model System UK Forecast (WRF-CMAQ) linked to City Model
(OSCAR)
Data Dashboard Online data viewing and retrieval tool
Daily city scale
forecast maps NO2, PM10 & PM2.5 3 day ahead high resolution maps
Population exposure Population exposure maps for NO2, PM10 & PM2.5 3
day ahead high resolution maps for Bristol and
Manchester
Air quality statistics NO2, O3, PM10 & PM2.5 trends and means via the
dashboard
Low Pollution and
exposure Routes Low pollution routes for active travel
Dr Aidan R Farrow a.farrow2@Herts.ac.uk

23. PROJECT OUTPUTS
Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Conclusions 1
• Collaboration provides useful insight
• City Authorities are interested in
• Spatial Data
• Forecast Data
For use in
• Environment Management
• Traffic Management
• Public Engagement
• NCAS Forecast now operates with an
interface for city scale modelling
Using Mesoscale Models to Forecast Air Quality in Cities

24. Dr Aidan R Farrow a.farrow2@Herts.ac.uk
Using Mesoscale Models to Forecast Air Quality in Cities
Conclusions 2
• Mesoscale Models – Regional to National Scale
E.g. The NCAS-UH Air Quality Forecast
• Regional scale signals contribute at the City scale
• Coupling Regional to Local models
E.g. The HiRAE Project
• Application of Regional-Local Forecasts
E.g. Working with Local Authorities

25. Thanks to:
Dr Vikas Singh, Dr Charles Chemel, Prof Ranjeet Sokhi
NERC (HiRAE), NCAS (Air Quality Forecast) and Defra
Bristol City Council
TfGM, Salford and Oldham Councils
FP7 Transphorm Dr Aidan Farrow a.farrow2@herts.ac.uk