Airnow

What Airnow MCP server does

Airnow exposes US EPA AirNow air-quality data through MCP. It covers current observed AQI for reporting areas, issued forecasts for today and up to three additional days, and hourly observations from individual monitoring sites. Data is available across US reporting areas and includes pollutant-specific values where AirNow publishes them.

The integration reads AirNow's public file products from files.airnowtech.org, rather than requiring credentials for the retired keyed web service. Responses include the source file URL, the upstream file's Last-Modified value as data_as_of, and a found indicator. Unsuccessful lookups return a structured reason and hint instead of a generic failure.

How it works

A hosted MCP connection uses the Pipeworx gateway endpoint at https://gateway.pipeworx.io/airnow/mcp. The gateway fetches and parses AirNow files when tools are called. A full Pipeworx gateway connection is also supported; the Airnow-scoped endpoint lists the Airnow tools directly and also exposes shared gateway meta-tools.

The npm package, @pipeworx/mcp-airnow, acts as a local stdio bridge. An MCP client starts it with npx, and the bridge forwards calls to the hosted gateway, so it still needs network access and has no offline mode. The gateway caches Airnow results for 10 minutes, while parsed source files use separate retention periods for reporting-area data, the ZIP index, and hourly observations.

Setup and configuration

Add the hosted endpoint to an MCP client:

{
  "mcpServers": {
    "airnow": {
      "url": "https://gateway.pipeworx.io/airnow/mcp"
    }
  }
}

For a local stdio connection, configure npx with the package name:

{
  "mcpServers": {
    "airnow": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-airnow"]
    }
  }
}

Anonymous npm-bridge usage is capped at 50 calls per day. A free Pipeworx account and PIPEWORX_API_KEY raise the limit to 200 calls per day. Set PIPEWORX_META_TOOLS=1 if the local bridge should also list the gateway-wide tools. The hosted HTTP tools can also be called directly through the Pipeworx REST interface.

Tools and capabilities

• current_by_zip finds the latest observed AQI by pollutant for the reporting area nearest a ZIP code. It can include other areas within a requested radius and yesterday's AQI.
• current_by_location performs the equivalent lookup from latitude and longitude.
• forecast_by_zip returns issued pollutant forecasts, Action Day status, and forecaster discussion. Supplying no date returns all available forecast days.
• observations_in_bbox retrieves hourly site observations for a minLon,minLat,maxLon,maxLat bounding box and UTC time range. It supports OZONE, PM25, PM10, NO2, CO, and SO2, with AQI available for the first four pollutants.

Limitations and notes

Hourly observation queries cover at most 24 hours per call, and each requested hour corresponds to a separate upstream file. The current hour may not yet be published; the response identifies those hours rather than treating them as an error. Forecasts several days ahead can contain a category with a null AQI because that is how the source agency may issue the forecast.

ZIP resolution uses the great-circle distance to a reporting area's published centroid, so a ZIP near a metropolitan boundary may resolve to a neighboring region. Use the returned alternative areas when that distinction matters. The npm bridge requires network access. Airnow is an independent, unofficial integration and is not affiliated with or endorsed by the EPA or AirNow.