Health tech · ESG · PropTech · Public sector
Actual pollution values per postcode, not just a city average.
DEFRA Modelled Background Pollution data provides annual mean NO2 and PM2.5 concentrations at 1km grid resolution — but joining it to postcodes requires spatial infrastructure most teams do not have. Zyfy does the join and returns the µg/m³ values directly, alongside green space proximity in metres and a national air quality percentile rank, on every postcode query.
Relevant signals
These fields are returned on every response and are ready to wire into your application logic.
| Signal | Relevance | What it tells you |
|---|---|---|
| signals.environment.no2UgM3 | Critical | Annual mean nitrogen dioxide concentration in µg/m³ for this postcode's 1km grid square. WHO guideline is 10 µg/m³. UK legal limit is 40 µg/m³. An EC1A postcode at 34 is well above the guideline but below the legal limit — the exact value, not just a colour code. |
| signals.environment.pm25UgM3 | Critical | Annual mean fine particulate matter in µg/m³. PM2.5 is the pollutant most strongly associated with long-term cardiovascular and respiratory harm. WHO guideline is 5 µg/m³. Return this to users who care about health impact, not just regulatory compliance. |
| signals.environment.greenSpaceProximityMetres | High | Distance in metres to the nearest public green space access point, computed from OS Open Greenspace. A direct, concrete signal — 520m to the nearest park is more useful than a "good access" band. |
| percentiles.airQuality | High | National air quality percentile (0–100; 100 = cleanest). p21 means this postcode has worse air than 79% of UK postcodes — a comparison that is immediately actionable in a health context. |
| signals.environment.airQualityBand | Medium | DEFRA DAQI-derived band: very_low, low, moderate, or high. Use for display or simple thresholds when the raw µg/m³ value is more precision than you need. |
Live example
A real-world request and the response it returns.
Request
curl https://zyfy.uk/v1/postcode/EC1A1BB \
-H "X-Api-Key: your_api_key"Response
{
"postcode": "EC1A 1BB",
"adminDistrict": "Islington",
"region": "London",
"signals": {
"environment": {
"airQualityBand": "moderate",
"no2UgM3": 34,
"pm25UgM3": 10,
"greenSpaceProximityMetres": 520,
"isNationalPark": false,
"isAonb": false
}
},
"percentiles": {
"airQuality": 21
}
}Example data is illustrative only. Responses shown include a subset of signals for clarity — the full response contains additional fields. See the signal reference for the complete list.
What you get
- ✓ Real values, not just categories — signals.environment.no2UgM3 = 34 tells you something specific. "moderate" tells you a category. For health applications, property disclosure, and ESG scoring, the number matters.
- ✓ WHO and UK limits built in context — The WHO guideline for NO2 is 10 µg/m³. The UK legal limit is 40. Both are documented in the signal reference — you have the benchmark alongside the value.
- ✓ Green space proximity as a health signal — Access to green space correlates with physical and mental health outcomes. OS Open Greenspace data is pre-joined to every postcode — no spatial query needed.
- ✓ Pairs naturally with liveability and EPC — scores.liveabilityScore already incorporates air quality and green space. Surface the composite for end users, and the raw µg/m³ values for technical or regulatory use cases.
Add environmental intelligence to your postcode lookups.
Free tier includes 100 requests per month. No credit card, no sales call.