Air Quality

See what variables and values are shown in your table

Variable	Visibility	Selected values	Action
Year	Shown in table	All 18 values	Change values
Pollutant	Shown in table	All 3 values	Change values
Area	Shown in table	All 30 values	Change values
Data description	Shown in table	µg/m3	Value cannot be changed

Table

Data values	Data description	Year	Pollutant	Area
14	µg/m3	2007	NO2	Wales
7	µg/m3	2007	NO2	Isle of Anglesey
7	µg/m3	2007	NO2	Gwynedd
10	µg/m3	2007	NO2	Conwy
9	µg/m3	2007	NO2	Denbighshire
13	µg/m3	2007	NO2	Flintshire
13	µg/m3	2007	NO2	Wrexham
7	µg/m3	2007	NO2	Ceredigion
9	µg/m3	2007	NO2	Pembrokeshire
9	µg/m3	2007	NO2	Carmarthenshire
14	µg/m3	2007	NO2	Swansea
14	µg/m3	2007	NO2	Neath Port Talbot
15	µg/m3	2007	NO2	Bridgend
14	µg/m3	2007	NO2	Vale of Glamorgan
22	µg/m3	2007	NO2	Cardiff
13	µg/m3	2007	NO2	Rhondda Cynon Taf
15	µg/m3	2007	NO2	Caerphilly
13	µg/m3	2007	NO2	Blaenau Gwent
15	µg/m3	2007	NO2	Torfaen
14	µg/m3	2007	NO2	Monmouthshire
24	µg/m3	2007	NO2	Newport
8	µg/m3	2007	NO2	Powys
13	µg/m3	2007	NO2	Merthyr Tydfil
10	µg/m3	2007	NO2	Betsi Cadwaladr University Health Board
8	µg/m3	2007	NO2	Powys Teaching Health Board

Showing 1 to 25 of 1,620 rows

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Metadata

The metadata for this dataset is not included when you download the data. You can download this separately. This contains all the information from the 'About this dataset' tab.

Next update expected:August 2026

Updates

• 2nd July 2026:

  2024 data added

• 31st October 2025: Dataset first published.

Main information

• Designation: No designation
• Data provider 1: Department for Environment, Food and Rural Affairs
• Data source 1: Air concentration
• Data provider 2: Welsh Government
• Data source 2: Geographical information
• Data provider 3: Office for National Statistics (ONS)
• Data source 3: Small Area Population Estimates (SAPE)
• Time period covered: January 2007 to December 2024

Overview

• Summary of dataset and variables:

  Air Quality Exposure Indicators - average, population weighted NO2, PM2.5 and PM10 concentrations across local authority areas and health board areas, derived from modelled data for each square kilometre in Wales, measured in µg/m3 (DEFRA data)

  µg/m3 = microgrammes per cubic metre NO2 = Nitrogen Dioxide PM10 = fine particulate matter with a diameter of 10 micrometers or less PM2.5 = fine particulate matter with a diameter of 2.5 micrometers or less

• Data collection or calculation:

  Each year the UK Government’s Pollution Climate Mapping (PCM) model calculates average pollutant concentrations for each square kilometre of the UK. The model is calibrated against measurements taken from the UK’s national air quality monitoring network.

  This data is combined with mid-year population data and dwelling data to provide population weighted data.

  For each census output area (statistical geographic units comprising around 150 properties), the pollutant concentrations are weighted by the number of dwellings in each square kilometre to give an average NO2, PM2.5 and PM10 concentration across the census output area.

  For each Local Authority and Local Health Board, a population-weighted average over its constituent census output areas were calculated to give an average NO2, PM2.5 and PM10 concentration based on where people live in those Local Authorities and Health Boards. The same calculation was also repeated over all census output areas, to give a comparable figure for the whole of Wales.

• Statistical quality:

  Each year the Pollution Climate Model (PCM) which underpin the background maps is refined and improved ( to account for latest available science and understanding e.g. changes in emissions factors, improved activity data etc.). These method changes are usually only applied in the latest year's figures. See Defra Air Quality report.

  2021 air quality figures are based on 2020 population estimates. 2023 air quality figures are based on 2022 population estimates.

• Rounding applied:

  whole number

• Related reports:
  • Modelled background pollution data
  • UK-Air GIS mapping

Published by

• Organisation: Welsh Government
• Contact email: stats.environment@gov.wales