# People in radon Affected Area squares

The share of residents who live in a 1 km square that the radon atlas marks as a radon Affected Area, where 1% or more of homes are estimated to be at or above the radon Action Level somewhere in the square.

Worked out by Open Index from the UKHSA and BGS radon atlas and census output areas.

## Facts

- Published by: British Geological Survey and UK Health Security Agency
- Level of detail: Middle area
- Updates: Every few years
- History: Since 2022
- Licence: Open Government Licence 3.0
- Method: Worked out by Open Index from the UKHSA and BGS radon atlas and census output areas
- Levels: United Kingdom, Nation, Region, Council, Constituency, Postcode area, Postcode district, Town, Ward, Middle area

## How it is worked out

Each census output area (each Data Zone in Northern Ireland) is placed in the 1 km square of the radon atlas that holds its label point, and its residents are counted there. The share is the residents in squares of class 2 or above (a radon Affected Area) out of all residents placed in a square, added up over the output areas in the area. Residents are the census count (2021, or 2022 in Scotland), and the mid-2024 estimate for Northern Ireland's Data Zones.

## Periods

| Level | First | Latest | Periods |
| --- | --- | --- | --- |
| United Kingdom | 2022 | 2022 | 1 |
| Nation | 2022 | 2022 | 1 |
| Region | 2022 | 2022 | 1 |
| Council | 2022 | 2022 | 1 |
| Constituency | 2022 | 2022 | 1 |
| Postcode area | 2022 | 2022 | 1 |
| Postcode district | 2022 | 2022 | 1 |
| Town | 2022 | 2022 | 1 |
| Ward | 2022 | 2022 | 1 |
| Middle area | 2022 | 2022 | 1 |

## Coverage

| Nation | Areas | With a figure |
| --- | --- | --- |
| England | 6856 | 6856 |
| Wales | 408 | 408 |
| Scotland | 1334 | 1334 |
| Northern Ireland | 850 | 850 |

## Caveats

- This counts people, not homes, and places each census output area at one point. It says how many people live where high radon is more likely, not how many homes have it.
- A radon Affected Area is a 1 km square where 1% or more of homes are estimated to be at or above the Action Level of 200 becquerels per cubic metre. Most homes in an Affected Area are below it.
- Each square takes the highest class found anywhere in it, so the share can be higher than a finer map would give.
- It is shown for wards and larger areas only. A neighbourhood sits in one or two squares, so its share would only repeat their class.

## Example: Hackney

About 2.0% of people in Hackney live in a 1 km square that the radon atlas marks as a radon Affected Area.
Across the UK the figure is 44.0%.
Worked out by Open Index from the UKHSA and BGS radon atlas and census output areas.

https://openindex.co.uk/hackney

## Sources

### Indicative atlas of radon (Great Britain and Northern Ireland)

- Publisher: British Geological Survey and UK Health Security Agency
- Licence: [Open Government Licence 3.0](https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/)
- Edition: Indicative Atlas of Radon: GB v3, NI v1
- Published: 1 December 2022
- Fetched: 19 October 2026
- Updates: irregular
- Credit: Contains British Geological Survey materials © UKRI 2022. Radon Potential classification UK Health Security Agency © Crown copyright 2022. Contains OS data © Crown copyright 2020. Contains public sector information licensed under the Open Government Licence v3.0.
- Publisher's page: https://www.bgs.ac.uk/datasets/radon-data-indicative-atlas-of-radon/

## Use it

- [The map](https://openindex.co.uk/map/radon-affected-areas)
- [Ranking](https://openindex.co.uk/rankings/radon-affected-areas/uk)
- Download (Middle area): https://data.openindex.co.uk/s/2026.10.8/downloads/layers/radon-affected-share/middle_area.csv
- API: https://openindex.co.uk/v1/layers/radon-affected-share

## How to cite

Source: Open Index, openindex.co.uk. Link to this page, https://openindex.co.uk/sources/radon-affected-areas.

Open Index's own text and the figures it works out are licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source data keeps its publishers' licences, named with each figure. Give each figure's period and source with it.

- Contains British Geological Survey materials © UKRI 2022. Radon Potential classification UK Health Security Agency © Crown copyright 2022. Contains OS data © Crown copyright 2020. Contains public sector information licensed under the Open Government Licence v3.0.
- Worked out by Open Index from the UKHSA and BGS radon atlas and census output areas.

Snapshot 2026.10.8, https://doi.org/10.5281/zenodo.23508850. The HTML page: https://openindex.co.uk/sources/radon-affected-areas