This map combines several open datasets to give a constituency-level picture of likely childhood lead-exposure risk in the UK. Each indicator is sourced and caveated below. Where coverage is partial (Scotland and Northern Ireland in particular), the limitation is documented alongside what was used as a fallback.
Geography
Parliamentary constituency boundaries (2024)
Westminster Parliamentary Constituencies July 2024 (UK BGC), from the ONS Open Geography Portal. 650 features, post-Boundary-Review names (PCON24NM, e.g. "Aberafan Maesteg" not pre-2024 "Aberavon"). Geometry simplified to ~2 MB at 0.002° tolerance using Shapely topology-preserving simplification — visually identical at country zoom.
Indicators
Blood lead ≥ 5 µg/dL (BLL)
Source: IHME Global Burden of Disease 2021 — Lead Exposure Estimates. Mean and 95% uncertainty interval for the proportion of the population with blood lead ≥ 5 µg/dL, by age group.
IHME publishes this at county / unitary-authority resolution in the UK, not at parliamentary-constituency level. The constituency map shows the value of the parent county / UA for each constituency (centroid-in-polygon match). Where no local data exists, falls back to nation-level (England, Scotland, Wales, NI) shown with reduced opacity.
Modelled children with BLL ≥ 5
A constituency-level allocation of the IHME national total for children 0–19
(~352,000 in the UK), produced in lead_exposure_model_FINAL.py
in this project. Risk weights:
- Pre-1950 housing share — odds ratio 1.92 (US CDC literature)
- IMD decile — odds ratio 1.44 for high deprivation
Each constituency's relative risk × child population gives a risk-weighted population; the IHME national total is allocated proportionally. This is illustrative; not a clinical estimate.
Housing built pre-1900 / pre-1945 / pre-1972 / pre-1992
The map exposes four cutoffs because UK lead-exposure pathways span different eras:
| Cutoff | Pathway |
|---|---|
| Pre-1900 | Lead service pipes + lead-pigment paint at peak |
| Pre-1945 | Lead-pigment paint dominant (US "pre-1950" CDC threshold) |
| Pre-1972 | Lead service pipes era (copper-with-lead-solder until 1987) |
| Pre-1992 | Any lead-paint exposure — UK consumer ban June 1992 (EU Dir. 89/677/EEC) |
Three sources are stitched together by nation:
England & Wales — VOA CTSOP 4.0 (2023)
Valuation Office Agency Council Tax Stock of Properties, table CTSOP4.0 (build period × council-tax band). LAD-level dwelling counts across detailed bands: pre-1900, 1900–1918, 1919–1929, 1930–1939, 1945–1954, 1955–1964, 1965–1972, 1973–1982, 1983–1992, etc. Aggregated to constituency via the ONS ward → constituency → LAD lookup, weighted by ward count.
Approximation: split-LAD constituencies (most of London, big metros) inherit each parent LAD's overall age profile in proportion to ward count. LSOA-level VOA data (CTSOP4.1) would give a sharper split-constituency result.
Scotland — SHCS 2017–2019
Scottish House Condition Survey: Local Authority Analysis 2017-2019, Stock Profile sheet. Sample-based estimates at LA level. Only the pre-1945 vs post-1945 split is published at LA level — the other cutoffs (pre-1900, pre-1972, pre-1992) are not available for Scotland and show as "no data" on those layers.
SHCS uses sample-based 3-year rolling estimates with confidence intervals. The 2017-2019 release is the most recent LA-level publication: 2020 had no survey, 2021 had non-comparable data, and the next LA release (2022-2024) won't appear until 2025.
Northern Ireland — NIHCS 2023 (NI-wide)
NI House Condition Survey 2023 Preliminary Report, Table 4. Bands: pre-1919, 1919-1944, 1945-1964, 1965-1980, 1981-1990, 1991-2002, 2003-2023. Only NI-wide values are published (the 2011 district-level report covers other measures, not age). The same NI-wide values are applied to all 18 NI constituencies.
Non-decent homes (Decent Homes Standard)
England: English Housing Survey: Local Authority Stock Modelling 2023, LA-level model based on EHS sample data combined with administrative records. A home fails the standard if any of the four criteria fail: HHSRS Category 1 hazard (which includes lead), disrepair of key components, lacks modern facilities, or inadequate thermal comfort.
Historic metal mines
The map combines two open inventories, deduplicated by ~500 m proximity:
- Macklin et al. (2023). WAPHA Global Metal Mines Database — supplementary data for the Science paper "Impacts of metal mining on river systems: a global assessment". UK subset: 137 sites.
- EA Inventory of Closed Mining Waste Facilities (2014) — Environment Agency / NRW open data under the Mining Waste Directive (2006/21/EC). 150 sites in E&W, 132 metalliferous, 146 flagged for water pollution. Open Government Licence v3.0.
Combined: 211 unique sites in 51 constituencies, mapped via point-in-polygon onto the 2024 boundaries. Lead-relevant commodities flagged (Pb, Zn, Cu, Ag, Ba/witherite — Pb often co-occurs in polymetallic veins).
Coverage gap: BGS BRITPITS holds >260,000 records including all historic UK workings (the comprehensive inventory) but is licensed by NERC and not openly downloadable. Cornwall is under-represented here as a result — the Camborne–Redruth historic tin/copper fields had thousands of small workings that aren't priority-polluting closures.
Constituency context
MP — name, party, email
Pulled from the UK Parliament Members API (January 2026 snapshot). Constituency names match the post-July-2024 boundaries.
Children aged 0–19
ONS mid-year population estimates aggregated to 2024 parliamentary constituencies.
IMD decile and deprivation score
Both come from the mySociety Composite UK IMD, which produces UK-wide comparable Index of Multiple Deprivation rankings (the nation-specific IMDs use different methodologies, so a composite is needed for cross-UK comparisons).
- IMD decile: 1 = most deprived 10% of UK constituencies, 10 = least deprived.
- Deprivation score: 0–100, higher = more deprived. Population-weighted percentile rank of LSOAs within UK.
Methodology notes & known limitations
- BLL is a county-level proxy. IHME doesn't publish constituency-level BLL; the value shown is the parent county / UA.
- Modelled children with BLL ≥ 5 is illustrative. It's a rough scaling of the IHME national total using housing-age and IMD risk weights from US CDC literature. Actual UK exposure rates and risk gradients may differ.
- Housing data is uneven across UK nations. England & Wales have rich VOA data with all four cutoffs; Scotland has only pre-1945 from SHCS LA tables; NI has all four cutoffs but applied uniformly NI-wide (no sub-NI data exists).
- Mines layer is not exhaustive. Only Macklin + EA closed waste — actual UK historic-mine inventory (BRITPITS) is much larger but licensed.
- Ward-weighting is an approximation. Constituencies that span multiple LADs are aggregated by ward count rather than dwelling count — fine for stable areas, less reliable in complex London/metro splits.
Data files in this repository
| File | What it contains |
|---|---|
uk_constituencies.json | 650 simplified 2024 constituency polygons |
IHME_GBD_2021_LEAD_RISK_*.CSV | BLL values by area and age group |
constituency_prewar_housing.csv | Housing-age cutoffs per constituency (E&W: VOA, Scot: SHCS, NI: NIHCS) |
constituency_uk_mines.csv | Mine counts (Macklin + EA IoCMWF, deduplicated) |
constituency_profile.csv | Single merged file all of the above plus MP, IMD, child population, model estimate |
Author: Lee Crawfurd, Center for Global Development. Source code: github.com/lcrawfurd/lead-map.