In 2025 the average resident of Dacorum lived with background NO₂ of 10.6 µg/m³, Very High for England and Wales and 1.1 times the WHO guideline of 10. PM2.5 was 8.4 µg/m³, Very High for England and Wales and 1.7 times the WHO guideline of 5. The typical area in England and Wales has NO₂ of 7.2 and PM2.5 of 7.4 µg/m³.
Modelled background levels averaged over where residents live (Census 2021), not roadside levels. Contains public sector information licensed under the Open Government Licence v3.0. Source: Defra modelled background pollution, 2025. How we calculate this
All house prices in DacorumBackground NO₂ in Dacorum is 10.6 µg/m³, 1.1 times the WHO guideline of 10, and higher than the typical area (7.2). That puts it in the Very High band. Background PM2.5 in Dacorum is 8.4 µg/m³, 1.7 times the WHO guideline of 5, and higher than the typical area (7.4). That puts it in the Very High band. Most of England and Wales is above the WHO guideline for PM2.5, so the bands compare places with each other rather than giving a pass or fail.
NO₂ level is Very High, on a scale from Very Low to Very High.
Very High means the highest fifth of areas in England and Wales for NO₂.
| Very Low | up to 4.7 |
|---|---|
| Low | 4.7 to 6.5 |
| Typical | 6.5 to 7.7 |
| High | 7.7 to 9.2 |
| Very High | over 9.2 |
WHO guideline: 10 µg/m³ (in the Very High band). UK legal limit: 40 µg/m³.
PM2.5 level is Very High, on a scale from Very Low to Very High.
Very High means the highest fifth of areas in England and Wales for PM2.5.
| Very Low | up to 6.0 |
|---|---|
| Low | 6.0 to 7.2 |
| Typical | 7.2 to 7.7 |
| High | 7.7 to 8.2 |
| Very High | over 8.2 |
WHO guideline: 5 µg/m³ (in the Very Low band). UK legal limit: 20 µg/m³, with a target of 10 µg/m³ in England by 2040.
The bands split every area we cover into fifths by its level, from Very Low to Very High. The map uses the same colours.
Little Gaddesden has the lowest background NO₂ of the 16 areas of Dacorum, at 7.8 µg/m³. Kings Langley has the highest, at 12.1 µg/m³. Average house prices are shown alongside, so you can weigh air quality against cost.
| Area | NO₂ | PM2.5 | NO₂ band | Average price |
|---|---|---|---|---|
| Little GaddesdenHigh | 7.8 | 7.9 | High | £2,314,500 |
| AldburyHigh | 7.9 | 7.9 | High | £672,750 |
| WiggintonHigh | 8.1 | 7.9 | High | £698,725 |
| Tring RuralHigh | 8.2 | 8.1 | High | £680,554 |
| TringHigh | 8.3 | 8.0 | High | £558,321 |
| Great GaddesdenHigh | 8.7 | 8.1 | High | £729,285 |
| NorthchurchHigh | 8.8 | 8.0 | High | £561,000 |
| Nettleden with Potten EndHigh | 8.9 | 8.1 | High | £877,400 |
| BovingdonVery High | 9.3 | 8.4 | Very High | £627,441 |
| BerkhamstedVery High | 9.4 | 8.1 | Very High | £800,034 |
| FlaundenVery High | 9.5 | 8.4 | Very High | £977,500 |
| MarkyateVery High | 9.9 | 8.3 | Very High | £407,900 |
| ChipperfieldVery High | 10.2 | 8.5 | Very High | £873,863 |
| FlamsteadVery High | 10.4 | 8.4 | Very High | £690,833 |
| Nash MillsVery High | 11.6 | 8.7 | Very High | £456,361 |
| Kings LangleyVery High | 12.1 | 8.8 | Very High | £641,041 |
Levels in µg/m³, 2025 annual average.
Background NO₂ in Dacorum compared with the 6 nearest other areas in Hertfordshire.
Open comparison
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No. These are background levels: yearly averages over 1 km squares, away from the immediate influence of roads. Right beside a busy road in Dacorum, NO₂ can be much higher. Councils publish roadside monitoring in their annual air quality reports.
More quick answers on house prices, sales, areas, green space, crime, air quality and listed buildings in Dacorum.
Price information is from HM Land Registry, location boundaries are from OpenStreetMap, and households and population are from Nomis Census 2021 postcode estimates (21 March 2021). Parks and green space are from OS Open Greenspace. Contains OS data © Crown copyright and database right 2026. Crime is from police.uk street-level data. Contains public sector information licensed under the Open Government Licence v3.0. Source: police.uk. Listed buildings and scheduled monuments are from Historic England and Cadw, and conservation areas from planning.data.gov.uk. © Historic England 2026. Contains Ordnance Survey data © Crown copyright and database right 2026. Source: planning.data.gov.uk, Open Government Licence v3.0. Air quality is from Defra modelled background pollution maps. Contains public sector information licensed under the Open Government Licence v3.0. Source: Defra modelled background pollution, 2025.
Last updated 11 November 2026 at 01:27 with the latest Land Registry data (September 2026). The Dacorum dataset covers 6,233 postcodes.
Contains HM Land Registry data © Crown copyright and database right 2026. This data is licensed under the Open Government Licence v3.0.
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