io.github.cyanheads/openaq-mcp-server

Historical measurement series for one pollutant at one station over a date range — for trend analysis and "was last week worse than the monthly average?". Pass a locationId and a parametersId and work in stations — you get the series for that pollutant at that station. Choose aggregation: raw (every reported value), hourly, or daily — daily and hourly add a per-bucket statistical summary (min, median, max, mean, sd). Large ranges produce thousands of rows and spill to a DataCanvas: the response returns a preview plus a canvasId and table name you query with openaq_dataframe_query. Values carry their unit; the server never converts between µg/m³, ppm, and ppb.

Latest measured value for every sensor at a monitoring station — the current-conditions tool. Returns one record per parameter, each with the value, its unit, the UTC and local timestamp, and the sensor id, joined so every value carries its pollutant and unit (the raw latest feed is keyed only by sensor id). Pass a locationId from openaq_find_locations, or pass coordinates to auto-resolve to the nearest station that measures the requested parametersId. Data recency varies by station reporting cadence — read each value's timestamp to know whether "latest" is minutes or hours old. These are measured observations with coverage gaps, not a modeled grid.

Catalog of country-level coverage: id, ISO code, name, the date span of available station data (datetimeFirst/datetimeLast), and which parameters are measured anywhere in that country. The availability check before a regional sweep — answers "which countries have NO2 monitoring?" and tells you whether a country has recent data before you call openaq_find_locations. Coverage is uneven worldwide; this surfaces where measured data exists.

Catalog of every measurable pollutant and its canonical unit: id, code, display name, unit, and a one-line description (pm25, pm10, o3, no2, so2, co, bc, and ~38 more). This is the unit-disambiguation reference — the same pollutant exists under several ids with different units (CO is id 4 in µg/m³, id 8 in ppm, id 102 in ppb), so use this to pick the exact parametersId for openaq_find_locations / openaq_get_readings / openaq_get_measurements and to interpret a reading's unit. A small bounded catalog fetched live from OpenAQ.