# AirScout: machine-payable air-quality queries over x402 (HTTP 402). Current US AQI and pollutants worldwide, an EPA-based verdict on outdoor exertion, and the cleanest window ahead for a session of a given length. Free preview at /preview; payment discovery at /.well-known/x402; A2A agent card at /.well-known/agent-card.json; A2A JSON-RPC at /a2a. Modelled data, not medical advice.