# Modelled background pollution data

### Introduction

Background pollution maps at 1x1 km resolution are modelled each year under Defra's Modelling of Ambient Air Quality (MAAQ) contract. These maps are used to provide policy support for Defra and to fulfil the UK's reporting obligations to Europe. They are also made publicly available for other research applications such as university studies, epidemiology and public health research, nature and conservation studies.

These maps should not be mistaken for the Local Authority-specific maps which are alternative maps based on the same model results as presented here but which provide source-sector splits and projections to future years by Local Authority to aid the Local Air Quality Management process.

Please acknowledge Defra as the source for this data if using the maps for your work.

Modelled estimates of population-weighted annual average PM_{2.5} concentrations suitable for use in estimating the mortality burden associated with long-term exposure to anthropogenic particulate air pollution at Local Authority level are presented in a later section of this page.

### Methodology

The models are continually updated and improved and so the methodology often changes each year. The most recent methodology report is for 2015 and can be found on the UK-AIR website: Report (PDF). Users should be mindful of these year to year changes when comparing model outputs between years.

### Updates

The maps are produced over the summer each year and typically the latest updates are checked and approved by the autumn and made available on this website by mid-October.

### File formats

The maps are all downloadable as .csv files for each year and each pollutant/metric as shown in the summary table below. Simply choose the output that you are interested in and click on the Download link (CSV) in the table.

Each file will contain some basic summary information about the dataset at the top of the file (the first four rows contain pollutant, year, metric and units). The data begins on row 6 of each file and contains 4 columns:

- a unique code (ukgridcode) for each 1x1km cell in the map
- the x coordinates for the centroid of each grid cell
- the y coordinates for the centroid of each grid cell
- the values for the metric itself.

The ukgridcode field allows several maps to be joined in a single file using that code as the lookup column.

### 'MISSING' values

There are some grid squares in each data set that do not have values associated with them and are labelled as ‘MISSING’. These are coastal squares for which the centre of the grid square is not located on the land and therefore the model does not provide a concentration for.

### Units

Most of the model outputs are annual means, represented in µg m^{-3}. CO concentrations are represented in mg m^{-3}. Specific units and information about the different metrics is provided in the summary table below.

### Additional notes

- PM data prior to 2004 was modelled in TEOM units. From 2004 onwards these were modelled in genuine gravimetric units.
- The models are calibrated using monitoring data from the national networks and in 2006 there were issues with the gravimetric PM analysers (Partisols). The monitoring data was subsequently reviewed and corrected and these changes were then incorporated into the modelling process to provide the final corrected grids. See the report Analysis of Trends in Gravimetric Particulate Mass Measurements in the United Kingdom (2.6MB PDF).

### Queries

For any queries about these maps, please contact Andrew Kent at andrew.kent@ricardo.com.

### Directory of maps

Jump to: PM_{10}, PM_{2.5}, NO_{x} and NO_{2}, CO, SO_{2}, Ozone, Benzene

#### PM_{10}

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

PM_{10} |
2001 | Annual mean | pm102001 | TEOM units | mappm102001 |

PM_{10} |
2002 | Annual mean | pm102002 | TEOM units | mappm102002 |

PM_{10} |
2003 | Annual mean | pm102003s15a | TEOM units | mappm102003s15a |

PM_{10} |
2004 | Annual mean | pm102004g | Gravimetric units | mappm102004g |

PM_{10} |
2005 | Annual mean | pm1005ac | Gravimetric units – corrected to account for updated Partisol monitoring concentrations1 | mappm1005ac |

PM_{10} |
2006 | Annual mean | pm102006gh | Gravimetric units – corrected to account for updated Partisol monitoring concentrations1 | mappm102006gh |

PM_{10} |
2007 | Annual mean | pm102007g | Gravimetric units | mappm102007g |

PM_{10} |
2008 | Annual mean | pm102008g | Gravimetric units | mappm102008g |

PM_{10} |
2009 | Annual mean | pm102009g | Gravimetric units | mappm102009g |

PM_{10} |
2010 | Annual mean | pm102010g | Gravimetric units | mappm102010g |

PM_{10} |
2011 | Annual mean | pm102011g | Gravimetric units | mappm102011g |

PM_{10} |
2012 | Annual mean | pm102012g | Gravimetric units | mappm102012g |

PM_{10} |
2013 | Annual mean | pm102013g | Gravimetric units | mappm102013g |

PM_{10} |
2014 | Annual mean | pm102014g | Gravimetric units | mappm102014g |

PM_{10} |
2015 | Annual mean | pm102015g | Gravimetric units | mappm102015g |

PM_{10} |
2016 | Annual mean | pm102016g | Gravimetric units | mappm102016g |

PM_{10} |
2017 | Annual mean | pm102017g | Gravimetric units | mappm102017g |

#### PM_{2.5}

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

PM_{2.5} |
2002 | Annual mean | pm252002 | mappm252002 | |

PM_{2.5} |
2003 | Annual mean | pm252003grav | mappm252003grav | |

PM_{2.5} |
2004 | Annual mean | pm252004g | mappm252004g | |

PM_{2.5} |
2005 | Annual mean | pm2505ac | corrected to account for updated Partisol monitoring concentrations1 | mappm2505ac |

PM_{2.5} |
2006 | Annual mean | pm252006gh | corrected to account for updated Partisol monitoring concentrations1 | mappm252006gh |

PM_{2.5} |
2007 | Annual mean | pm252007g | mappm252007g | |

PM_{2.5} |
2008 | Annual mean | pm252008g | mappm252008g | |

PM_{2.5} |
2009 | Annual mean | pm252009g | mappm252009g | |

PM_{2.5} |
2010 | Annual mean | pm252010g | mappm252010g | |

PM_{2.5} |
2011 | Annual mean | pm252011g | mappm252011g | |

PM_{2.5} |
2012 | Annual mean | pm252012g | mappm252012g | |

PM_{2.5} |
2013 | Annual mean | pm252013g | mappm252013g | |

PM_{2.5} |
2014 | Annual mean | pm252014g | mappm252014g | |

PM_{2.5} |
2015 | Annual mean | pm252015g | mappm252015g | |

PM_{2.5} |
2016 | Annual mean | pm252016g | mappm252016g | |

PM_{2.5} |
2017 | Annual mean | pm252017g | mappm252017g |

#### NO_{x} and NO_{2}

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

NO_{2} |
2001 | Annual mean | no22001_3 | mapno22001_3 | |

NO_{2} |
2002 | Annual mean | no22002_1 | mapno22002_1 | |

NO_{2} |
2003 | Annual mean | no22003 | mapno22003 | |

NO_{2} |
2004 | Annual mean | no22004 | mapno22004 | |

NO_{2} |
2005 | Annual mean | no22005 | mapno22005 | |

NO_{2} |
2006 | Annual mean | no22006 | mapno22006 | |

NO_{2} |
2007 | Annual mean | no22007 | mapno22007 | |

NO_{2} |
2008 | Annual mean | no22008 | mapno22008 | |

NO_{2} |
2009 | Annual mean | no22009 | mapno22009 | |

NO_{2} |
2010 | Annual mean | no22010 | mapno22010 | |

NO_{2} |
2011 | Annual mean | no22011 | mapno22011 | |

NO_{2} |
2012 | Annual mean | no22012 | mapno22012 | |

NO_{2} |
2013 | Annual mean | no22013 | mapno22013 | |

NO_{2} |
2014 | Annual mean | no22014 | mapno22014 | |

NO_{2} |
2015 | Annual mean | no22015 | mapno22015 | |

NO_{2} |
2016 | Annual mean | no22016 | mapno22016 | |

NO_{2} |
2017 | Annual mean | no22017 | mapno22017 | |

NO_{X} |
2001 | Annual mean | nox2001_3 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2001_3 |

NO_{X} |
2002 | Annual mean | nox2002_1 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2002_1 |

NO_{X} |
2003 | Annual mean | nox2003 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2003 |

NO_{X} |
2004 | Annual mean | nox2004 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2004 |

NO_{X} |
2005 | Annual mean | nox2005 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2005 |

NO_{X} |
2006 | Annual mean | nox2006 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2006 |

NO_{X} |
2007 | Annual mean | nox2007 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2007 |

NO_{X} |
2008 | Annual mean | nox2008 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2008 |

NO_{X} |
2009 | Annual mean | nox2009 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2009 |

NO_{X} |
2010 | Annual mean | nox2010 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2010 |

NO_{X} |
2011 | Annual mean | nox2011 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2011 |

NO_{X} |
2012 | Annual mean | nox2012 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2012 |

NO_{X} |
2013 | Annual mean | nox2013 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2013 |

NO_{X} |
2014 | Annual mean | nox2014 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2014 |

NO_{X} |
2015 | Annual mean | nox2015 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2015 |

NO_{x} |
2016 | Annual mean | nox2016 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2016 |

NO_{x} |
2017 | Annual mean | nox2017 | µg m^{-3} (NO_{X} as NO_{2}) |
mapnox2017 |

#### CO

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

CO | 2002 | Annual mean | coamean2002_1 | Units are mg m^{-3} |
mapcoamean2002_1 |

CO | 2003 | Annual mean | coamean2003_1 | Units are mg m^{-3} |
mapcoamean2003_1 |

CO | 2004 | Annual mean | coamean2004_1 | Units are mg m^{-3} |
mapcoamean2004_1 |

CO | 2005 | Annual mean | coamean2005 | Units are mg m^{-3} |
mapcoamean2005 |

CO | 2006 | Annual mean | coamean2006 | Units are mg m^{-3} |
mapcoamean2006 |

CO | 2007 | Annual mean | coamean2007 | Units are mg m^{-3} |
mapcoamean2007 |

CO | 2008 | Annual mean | coamean2008 | Units are mg m^{-3} |
mapcoamean2008 |

CO | 2009 | Annual mean | coamean2009 | Units are mg m^{-3} |
mapcoamean2009 |

CO | 2010 | Annual mean | coamean2010 | Units are mg m^{-3} |
mapcoamean2010 |

CO | 2002 | Max 8-hr mean | co8hr2002_1 | Units are mg m^{-3} |
mapco8hr2002_1 |

CO | 2003 | Max 8-hr mean | co8hr2003_1 | Units are mg m^{-3} |
mapco8hr2003_1 |

CO | 2004 | Max 8-hr mean | com8hr2004_1 | Units are mg m^{-3} |
mapcom8hr2004_1 |

CO | 2005 | Max 8-hr mean | com8hr2005 | Units are mg m^{-3} |
mapcom8hr2005 |

CO | 2006 | Max 8-hr mean | com8hr2006 | Units are mg m^{-3} |
mapcom8hr2006 |

CO | 2007 | Max 8-hr mean | com8hr2007 | Units are mg m^{-3} |
mapcom8hr2007 |

CO | 2008 | Max 8-hr mean | com8hr2008 | Units are mg m^{-3} |
mapcom8hr2008 |

CO | 2009 | Max 8-hr mean | com8hr2009 | Units are mg m^{-3} |
mapcom8hr2009 |

CO | 2010 | Max 8-hr mean | com8hr2010 | Units are mg m^{-3} |
mapcom8hr2010 |

#### SO_{2}

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

SO_{2} |
2002 | Annual mean | so202annd | mapso202annd | |

SO_{2} |
2003 | Annual mean | so203ann | mapso203ann | |

SO_{2} |
2004 | Annual mean | so204ann | mapso204ann | |

SO_{2} |
2005 | Annual mean | so205ann | mapso205ann | |

SO_{2} |
2006 | Annual mean | so206ann | mapso206ann | |

SO_{2} |
2007 | Annual mean | so207ann | mapso207ann | |

SO_{2} |
2008 | Annual mean | so208ann | mapso208ann | |

SO_{2} |
2009 | Annual mean | so209ann | mapso209ann | |

SO_{2} |
2010 | Annual mean | so210ann | mapso210ann | |

SO_{2} |
2011 | Annual mean | so211ann | mapso211ann | |

SO_{2} |
2012 | Annual mean | so212ann | mapso212ann | |

SO_{2} |
2013 | Annual mean | so213ann | mapso213ann | |

SO_{2} |
2014 | Annual mean | so214ann | mapso214ann | |

SO_{2} |
2015 | Annual mean | so215ann | mapso22015 | |

SO_{2} |
2016 | Annual mean | so116ann | mapso22016 | |

SO_{2} |
2017 | Annual mean | so117ann | mapso22017 |

#### Ozone

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

Ozone | 2003 | DGT120 | daysgt12003_2 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdaysgt12003_2 |

Ozone | 2004 | DGT120 | dgt12004 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt12004 |

Ozone | 2005 | DGT120 | dgt120_2005r | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_2005r |

Ozone | 2006 | DGT120 | dgt120_06 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_06 |

Ozone | 2007 | DGT120 | dgt120_07 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_07 |

Ozone | 2008 | DGT120 | dgt120_08 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_08 |

Ozone | 2009 | DGT120 | dgt120_09 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_09 |

Ozone | 2010 | DGT120 | dgt120_10 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_10 |

Ozone | 2011 | DGT120 | dgt120_11 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_11 |

Ozone | 2012 | DGT120 | dgt120_12 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_12 |

Ozone | 2013 | DGT120 | dgt120_13 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_13 |

Ozone | 2014 | DGT120 | dgt120_14 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_14 |

Ozone | 2015 | DGT120 | dgt120_15 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_15 |

Ozone | 2016 | DGT120 | dgt120_16 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_16 |

Ozone | 2017 | DGT120 | dgt120_17 | metric is number of days on which the daily max 8-hr concentration is greater than 120 µg m^{-3} |
mapdgt120_17 |

#### Benzene

Pollutant | Year | Metric | Header label | Comments | Download link (CSV) |
---|---|---|---|---|---|

Benzene | 2003 | Annual mean | bz2003 | mapbz2003 | |

Benzene | 2004 | Annual mean | bz2004 | mapbz2004 | |

Benzene | 2005 | Annual mean | bz2005 | mapbz2005 | |

Benzene | 2006 | Annual mean | bz2006 | mapbz2006 | |

Benzene | 2007 | Annual mean | bz2007 | mapbz2007 | |

Benzene | 2008 | Annual mean | bz2008 | mapbz2008 | |

Benzene | 2009 | Annual mean | bz2009 | mapbz2009 | |

Benzene | 2010 | Annual mean | bz2010 | mapbz2010 | |

Benzene | 2011 | Annual mean | bz2011 | mapbz2011 | |

Benzene | 2012 | Annual mean | bz2012 | mapbz2012 | |

Benzene | 2013 | Annual mean | bz2013 | mapbz2013 | |

Benzene | 2014 | Annual mean | bz2014 | mapbz2014 | |

Benzene | 2015 | Annual mean | bz2015 | mapbz2015 | |

Benzene | 2016 | Annual mean | bz2016 | mapbz2016 | |

Benzene | 2017 | Annual mean | bz2017 | mapbz2017 |

### Population-weighted annual mean PM_{2.5} data

These data are population-weighted annual mean concentrations (µg m^{-3}) for each Local Authority. These data are suitable for use in estimating the burden of mortality attributable to long-term exposure to particulate air pollution using methods such as those recommended by COMEAP in its statement "Estimating the mortality burden of particulate air pollution at the local level" and used in calculating the Public Health Outcomes Framework indicator "Fraction of Mortality Attributable to Particulate Air Pollution".

Concentrations of anthropogenic, rather than total, PM_{2.5} are used as the basis for this indicator, as burden estimates based on total PM_{2.5} might give a misleading impression of the scale of the potential influence of policy interventions (COMEAP, 2012). However, modelled concentrations of anthropogenic PM_{2.5} are more uncertain than those of total PM_{2.5} because of the uncertainty associated with the assignment to anthropogenic and non-anthropogenic sources.

Background annual average PM_{2.5} concentrations for the year of interest are modelled on a 1km x 1km grid using an air dispersion model (Pollution Climate Mapping), and calibrated using measured concentrations taken from background sites in Defra's Automatic Urban and Rural Network. Data on primary emissions from different sources from the National Atmospheric Emissions Inventory and a combination of measurement data for secondary inorganic aerosol and models for sources not included in the emission inventory (including re-suspension of dusts) are used to estimate the anthropogenic (human-made) component of these concentrations. By approximating LA boundaries to the 1km by 1km grid, and using census population data, population weighted background PM_{2.5} concentrations for each lower tier LA are calculated. This work is completed under contract to Defra, as a small extension of its obligations under the Ambient Air Quality Directive (2008/50/EC).

The data are available from the download links in the table below on an annual basis. Estimated concentrations are population-weighted annual mean PM_{2.5} in µg m^{-3}. For 2010 the data are provided for UK by Local Authority only. For 2011 onwards, the data are provided for UK by Local Authority and by country. Data are also provided for England by region and upper tier Local Authority. Each data file includes the fields below.

- Code (LA code/Region code/Country code– an identifier for each local authority (follows the established UWE code)
- 'PM
_{2.5}[YEAR] (total)' – total estimated PM_{2.5}concentration - 'PM
_{2.5}[YEAR] (non-anthropogenic)' – estimated non-anthropogenic PM_{2.5}concentration - 'PM
_{2.5}[YEAR] (anthropogenic)' – estimated anthropogenic PM_{2.5}concentration - Name (Local authority name/Region name/Country name)

Pollutant | Year | Metric | Download link (CSV) |
---|---|---|---|

PM_{2.5} |
2010 | Population-weighted annual mean (by local authority) | popwmpm252010byUKlocalauthority.csv |

PM_{2.5} |
2011 | Population-weighted annual mean (by local authority) | popwmpm252011byUKlocalauthority.csv |

PM_{2.5} |
2011 | Population-weighted annual mean (by region) | popwmpm252011byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2011 | Population-weighted annual mean (by country) | popwmpm252011byUKcountry.csv |

PM_{2.5} |
2012 | Population-weighted annual mean (by local authority) | popwmpm252012byUKlocalauthority.csv |

PM_{2.5} |
2012 | Population-weighted annual mean (by region) | popwmpm252012byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2012 | Population-weighted annual mean (by country) | popwmpm252012byUKcountry.csv |

PM_{2.5} |
2013 | Population-weighted annual mean (by local authority) | popwmpm252013byUKlocalauthority.csv |

PM_{2.5} |
2013 | Population-weighted annual mean (by region) | popwmpm252013byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2013 | Population-weighted annual mean (by country) | popwmpm252013byUKcountry.csv |

PM_{2.5} |
2014 | Population-weighted annual mean (by local authority) | popwmpm252014byUKlocalauthority.csv |

PM_{2.5} |
2014 | Population-weighted annual mean (by region) | popwmpm252014byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2014 | Population-weighted annual mean (by country) | popwmpm252014byUKcountry.csv |

PM_{2.5} |
2015 | Population-weighted annual mean (by local authority) | popwmpm252015byUKlocalauthority.csv |

PM_{2.5} |
2015 | Population-weighted annual mean (by region) | popwmpm252015byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2015 | Population-weighted annual mean (by country) | popwmpm252015byUKcountry.csv |

PM_{2.5} |
2016 | Population-weighted annual mean (by local authority) | popwmpm252016byUKlocalauthority.csv |

PM_{2.5} |
2016 | Population-weighted annual mean (by region) | popwmpm252016byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2016 | Population-weighted annual mean (by country) | popwmpm252016byUKcountry.csv |

PM_{2.5} |
2017 | Population-weighted annual mean (by local authority) | popwmpm252017byUKlocalauthority.csv |

PM_{2.5} |
2017 | Population-weighted annual mean (by region) | popwmpm252017byEnglandregionanduppertierlocalauthority.csv |

PM_{2.5} |
2017 | Population-weighted annual mean (by country) | popwmpm252017byUKcountry.csv |