# The unofficial air

> Cheap sensors on people's balconies, denser than the official network.

- Category: Environment
- Cadence: live
- Status: Live: values change continuously; cite the retrieval time.
- Dataset key: `live-sensors`
- Source: [Sensor.Community](https://sensor.community/)
- Licence: Database Contents Licence (DbCL) v1.0 — [terms](https://opendatacommons.org/licenses/dbcl/1-0/)
- Canonical page: [https://londongraph.com/g/the-unofficial-air](https://londongraph.com/g/the-unofficial-air)
- Machine-readable record: [https://londongraph.com/data/the-unofficial-air](https://londongraph.com/data/the-unofficial-air)

## Methodology

Live PM2.5 readings from Sensor.Community, a global network of self-built citizen sensors. This sits deliberately beside the official LondonAir gauge elsewhere in this atlas: the official network is about a hundred calibrated sites publishing an index the government stands behind, and this is hundreds of uncalibrated ones publishing whatever is in front of them. Sensors marked indoor are dropped, and readings of zero or above 1,000 µg/m³ are treated as a stuck device rather than as air. Nothing here is an official measurement. Colour is banded against the WHO 24-hour guideline of 15 µg/m³.

## Visualisations

- [Map](https://londongraph.com/g/the-unofficial-air): Cheap sensors on people's balconies, denser than the official network.
- [Hotspots](https://londongraph.com/g/the-unofficial-air?view=hotspots): Compare the same measure geographically.

## Citation guidance

Attribute the original publisher named above and identify LondonGraph as the visualisation and methodology layer. Do not describe live values as a historical census, and do not present placeholder values as observations.