# Polkadot already holds an open dataset of the planet's air: 19M+ readings from citizen sensors

**URL:** <https://forum.polkadot.network/t/polkadot-already-holds-an-open-dataset-of-the-planets-air-19m-readings-from-citizen-sensors/19488>\
**Category:** Ecosystem\
**Created:** [November 13, 2026, 6:45pm UTC](https://forum.polkadot.network/t/polkadot-already-holds-an-open-dataset-of-the-planets-air-19m-readings-from-citizen-sensors/19488 "2026-11-13T18:45:12Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ensrationis](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.polkadot.network/ensrationis/32/7927_2.png) [@ensrationis](https://forum.polkadot.network/u/ensrationis)\
**Post date:** [November 13, 2026, 6:45pm UTC](https://forum.polkadot.network/t/polkadot-already-holds-an-open-dataset-of-the-planets-air-19m-readings-from-citizen-sensors/19488/1 "2026-11-13T18:45:12Z")

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People often say that one day data will live on chain. Here is a case where it already does, and where the main result of using a blockchain is not financial.

Since April 2026, home air sensors in Cyprus, on Koh Phangan in Thailand, on Réunion, across Europe and in 20+ countries have been sending their readings through Robonomics. Since 28 September, when Robonomics moved to Polkadot, the record lives on Polkadot.

 ![numbers](https://europe1.discourse-cdn.com/flex005/uploads/polkadot2/original/2X/2/25874deebebaf7e7fde7ffc468aeda45dffbb7d6.png)

**What has piled up** (counted on 13 November, from 1 April, when the current index starts):

- 19M+ readings, 100M+ individual values: fine and coarse dust, temperature, humidity, pressure, street noise, CO₂ indoors
- 100+ sensors in 20+ countries
- almost half a million entries on chain

Earlier readings are on chain too and will be re-indexed, so these numbers are floors.

 ![map](https://europe1.discourse-cdn.com/flex005/uploads/polkadot2/original/2X/c/ca218dcd41c7af9faddf10b601dcb6b49d43229d.png)

**What the data has already shown**

- Koh Phangan: very clean background air, with about 1,200 short, sharp pollution episodes inside it, mostly in the evening and right next to a single sensor. That is daily household trash burning. Local activists now use it as evidence that sits on a public chain. Analysis: [Koh Phangan, one year on: what a network built in two days actually found](https://sensors.social/blog/koh-phangan-one-year-later/)
- Cyprus: 25+ sensors followed a Saharan dust storm hour by hour across the island, from Paphos to Nicosia and Famagusta. One official station shows one dot; two dozen neighbours show the front moving.

 ![episodes](https://europe1.discourse-cdn.com/flex005/uploads/polkadot2/original/2X/f/f3517cba1e05e5ede12520e72beaf00702eb7585.png)

**Why a chain**

Each sensor signs its own readings. Batches go to IPFS, and the fingerprint of every batch is written to Robonomics on Polkadot. Change one number later and it no longer matches. The indexer is open source, so anyone can rebuild the whole archive from the chain without asking us.

**Why it matters for Polkadot**

This is a commons: a city, a university lab and a student get the same data on the same terms, under an open licence (ODbL), and nobody, including us, can close it. Polkadot here is infrastructure for a public good, not only for finance.

- Live map: [https://sensors.social](https://sensors.social)
- Open API: [An open air dataset for the planet — built so it stays open](https://sensors.social/blog/open-air-dataset/)
- Full story: `robonomics.network/blog/open-air-dataset-on-polkadot/`

We would be glad to hear from researchers who want to use the data, and from anyone who wants to add a sensor to the map.