Cells in a box

GET /v1/cells — every reporting area in a bounding box, for building your own map.

GET/v1/cells

curl -H "Authorization: Bearer $OPENAQI_KEY" \
  "https://openaqi.net/api/v1/cells?bbox=-122.6,37.2,-121.7,37.9&metric=pm2p5"

Parameters

Name	Type	Default	Notes
`bbox`	string	—	`west,south,east,north` in degrees. Required. Max 30° per side.
`metric`	string	`pm2p5`	Which metric to return.
`window`	integer	`60`	Minutes to average over.
`limit`	integer	`1000`	Max 5000.

The response

{
  "data": {
    "metric": "pm2p5",
    "unit": "µg/m³",
    "cells": [
      {
        "cell": "608693243097382911",
        "centre": { "lat": 37.4752, "lon": -121.7375 },
        "value": 12.4,
        "severity": "moderate",
        "sensors": 2,
        "updated_at": "2026-08-02T09:10:00.000Z"
      }
    ]
  }
}

Centres and numbers rather than our polygons, so you can render it your way. Compute the hexagon from the H3 index with any H3 library:

import { cellToBoundary } from "h3-js";
const ring = cellToBoundary(BigInt(cell).toString(16), true); // [lng, lat] pairs

Use severity rather than interpolating over the values you received. Severity is anchored to published thresholds, so an all-green map means the air really is fine — a relative scale would paint the worst cell in a clean city red.

The band colours are in /v1/meta.

Notes

A box crossing the antimeridian is rejected rather than half-answered. Split it into two requests.
Exactly limit cells returned means there may be more; meta.truncated says so.

Parameters

The response

Colouring it

Notes

On this page