What does this dataset tell me?

For any UK address, it tells you whether the property is inside a declared Air Quality Management Area and, if so, for which pollutant. It also returns the local authority that declared the zone, its ONS code, the zone name and description, the area in square kilometres, and the boundary polygon.

Where does the data come from?

From a single national source, the DEFRA UK-AIR national AQMA register. DEFRA maintains the register and local authorities declare and revoke the zones. Boundaries are served as polygons in EPSG:4326.

How current is it and how often does it change?

The register is snapshot-versioned as councils declare or revoke zones, roughly quarterly. Every response carries a snapshot id and source dataset version, and you can pin the snapshot id to reproduce a past result.

Which pollutants can trigger a declaration?

Zones in this dataset are declared for NO2, PM10, SO2 or benzene. Each AQMA records which of these triggered it, together with the limit-value type that was breached. A single zone can be declared for more than one pollutant.

How do I access it, and does it cost extra?

AQMA membership is returned as part of any Air Quality API location query, or you can pull the underlying polygon dataset. Regulatory zone membership, including AQMAs, is part of the free tier of the Air Quality API.

The AQMA register is published under the Open Government Licence v3.0, with attribution to DEFRA and the declaring local authorities.

Live

Environmental & Hazards

New

Air Quality Management Areas

Tells you if a UK address sits inside a declared Air Quality Management Area, for which pollutant, and which local authority declared it.

~460

Declared AQMAs

Whole UK

Coverage

Quarterly

Update cadence

Environment Act 1995, Part IV

Statutory basis

Overview

About this dataset

An Air Quality Management Area (AQMA) is a zone a local authority must legally declare where statutory air quality objectives are not being met, and for which it must produce an action plan. The legal basis is Part IV of the Environment Act 1995, the Local Air Quality Management regime. Around 460 AQMAs are currently declared across the UK. This dataset answers, for any address: is the property inside one, and for which pollutant was it declared.

The data comes from a single national source, the DEFRA UK-AIR national AQMA register, with the declaring local authority identified by its ONS code. Each zone carries a title and description, its area in square kilometres, and per-pollutant declaration flags for NO2, PM10, SO2 and benzene, along with the limit-value type that was breached. Boundaries are served as polygons in EPSG:4326.

You can query it two ways. As zone membership on any location query through the Air Quality API, which returns whether the point falls inside an AQMA and the distance to the nearest boundary. Or as the underlying polygon dataset, for spatial joins and map rendering.

The register is snapshot-versioned as councils declare or revoke zones, roughly quarterly, and every response carries a snapshot id you can pin for reproducibility. Custodians are DEFRA, which maintains the register, and the local authorities that declare and revoke the zones. The licence is the Open Government Licence v3.0.

What's included

Everything in the box

Inside-or-outside test on any address

A point query returns a boolean for whether the property falls inside a declared AQMA, plus the distance in metres to the nearest boundary if it does not.

Per-pollutant declaration flags

Each zone records which pollutants triggered the declaration, from NO2, PM10, SO2 and benzene, and the limit-value type that was breached.

Declaring authority with ONS code

Every AQMA carries the name of the local authority that declared it and its ONS code, so you can join to other administrative datasets.

Polygons in EPSG:4326

Boundaries are served as polygons in WGS84, ready for spatial joins, map rendering, or intersection against your own sites.

Two access shapes

Read AQMA membership as part of any Air Quality API location query, or pull the underlying polygon dataset directly.

Snapshot versioning for reproducibility

Councils declare and revoke zones over time. Every response carries a snapshot id you can pin, so a result you record today can be reproduced later.

Data fields

What each record carries

schema11 fields

aqmaRef: string// Register reference for the declared AQMA.

name: string// Title of the AQMA as declared.

localAuthority: string// Local authority that declared the zone.

onsCode: string// ONS code of the declaring local authority.

inside: boolean// Whether the queried point falls inside this AQMA.

distanceM: number// Distance in metres from the queried point to the AQMA boundary. Zero or absent when inside.

declaredPollutants: array// Pollutants the zone was declared for, from no2, pm10, so2 and benzene.

limitValueType: string// The limit-value type that was breached and triggered the declaration.

areaKm2: float// Area of the AQMA in square kilometres.

geometry: object// Boundary polygon in EPSG:4326 (WGS84).

snapshotId: string// Version id of the register snapshot this result came from. Pin it to reproduce the result.

Sample response

Straight from the API

response.jsonapplication/json

{
  "aqmaRef": "0123",
  "name": "City Centre AQMA",
  "localAuthority": "Leeds City Council",
  "onsCode": "E08000035",
  "inside": true,
  "distanceM": 0,
  "declaredPollutants": ["no2"],
  "limitValueType": "annual mean",
  "areaKm2": 2.4,
  "geometry": {
    "type": "Polygon",
    "coordinates": [
      [
        [-1.55, 53.80],
        [-1.54, 53.80],
        [-1.54, 53.81],
        [-1.55, 53.81],
        [-1.55, 53.80]
      ]
    ]
  },
  "snapshotId": "aqma-2026-q2"
}

Use cases

What people build with it

Flag an air quality planning constraint at site appraisal

Check whether a development site sits inside an AQMA before submission. An AQMA declaration signals that the local authority has an action plan and may attach air quality conditions or require mitigation, which affects design and cost.

Developers

Screen a portfolio for regulatory air quality exposure

Run a batch of addresses against the register to identify which properties fall inside declared AQMAs and for which pollutant. Useful for lending and investment due diligence where a zone declaration is a material environmental fact.

Lenders

Record an air quality fact in a property report

Return a clear inside-or-outside answer, the declaring authority and its ONS code, and the pollutant declared, sourced from the DEFRA national register and stamped with a snapshot id for the file.

Surveyors

Cross-reference AQMAs against local plan policy

Intersect AQMA polygons with sites and allocations to see where air quality objectives are not being met, which informs where mitigation or monitoring conditions are likely.

Planners

Embed an air quality zone check in a property app

Add a single API call that tells the user whether an address is inside an AQMA and which pollutant caused it, backed by the national DEFRA register rather than manual council lookups.

PropTech