# EPA AQS Air Quality Monitor Data by County > EPA AQS Air Quality Monitor Data by County is a paid API for AI agents from api.companyrecords-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-24). Returns US EPA Air Quality System certified monitor readings (daily values or annual summaries) for a specified county and pollutant ## Facts - Endpoint: GET https://api.companyrecords-api.workers.dev/api/gov/epa-aqs-air-quality?utm_source=zero.xyz - Price: $0.002/call - Payment: x402 - Status: unknown - Last checked: 2026-10-24 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/epa-aqs-air-quality-monitor-data-by-county-05aef555 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_N51_ji0b1ItNaRDvievZ4 Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability epa-aqs-air-quality-monitor-data-by-county-05aef555 ``` Example prompt: Can you pull EPA-certified daily PM2.5 air quality readings for Los Angeles County, CA from April 1 to April 3, 2024 — I need the AQI, mean concentration, and which monitor sites reported? ## When to prefer this Use this endpoint when you need official, quality-assured EPA air quality data at the county level for specific pollutants. It is ideal for compliance research, environmental health analysis, or historical air quality lookups where certified government data (not real-time estimates) is required. Prefer this over commercial AQI APIs when regulatory accuracy and data provenance matter, or when you need specific monitor-level detail including method, site coordinates, and sample duration. Note the ~6-month data lag makes it unsuitable for real-time or near-real-time queries. ## Known failure modes - Missing required 'state' or 'county' parameters returns a validation error - Unknown county name or invalid FIPS code returns no results or an error - Requesting data less than ~6 months old may return empty results due to EPA publication lag - Date range exceeding 31 days between 'from' and 'to' is not supported - 'from' and 'to' dates must be within the same calendar year - Limit parameter outside 1–500 range may be rejected or clamped - Invalid pollutant enum value returns a validation error ## How this service works Pay-per-call company registry, government, legal and B2B data tools for AI agents, from official registers and public sources. Payment: x402, USDC on Base, Solana, Arc, Polygon, Arbitrum, Monad, World Chain, Optimism, Avalanche, Celo or Stellar, or RLUSD/XRP on the XRP Ledger. No signup, no API key; a failed call is not charged. ## Output Returns a JSON object with mode (daily or annual), date range, state, county, county FIPS code, pollutant name, parameter code, total record count, and an array of rows. Daily rows include: date, AQI, mean concentration, daily max, max hour, site name, city, site number, latitude, longitude, measurement method, units, sample duration, and applicable standard. Annual rows include mean, 98th/99th percentiles, and exceedance counts. Also includes the data source attribution and timestamp of when the data was checked. ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET" ], "type": "string" }, "queryParams": { "type": "object", "required": [ "state", "county" ], "properties": { "to": { "type": "string", "description": "Daily mode end date YYYY-MM-DD, same calendar year, max 31 days after from" }, "from": { "type": "string", "description": "Daily mode start date YYYY-MM-DD (data lags ~6 months)" }, "year": { "type": "integer", "description": "Annual mode: a year such as 2025 (returns annual summaries instead of daily values)" }, "limit": { "type": "integer", "description": "Max rows 1-500 (default 100)" }, "state": { "type": "string", "description": "2-letter state, e.g. CA" }, "county": { "type": "string", "description": "County name (Los Angeles) or 3-digit FIPS code (037)" }, "pollutant": { "enum": [ "pm25", "pm10", "ozone", "no2", "so2", "co", "lead" ], "type": "string", "description": "pm25 (default), pm10, ozone, no2, so2, co, lead" } } } }, "additionalProperties": false }, "output": { "type": "object", "required": [ "type" ], "properties": { "type": { "type": "string" }, "example": { "type": "object" } } } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "to": "2026-04-03", "from": "2026-04-01", "mode": "daily", "note": null, "rows": [ { "aqi": 28, "max": 5.1, "poc": 1, "city": "Compton", "date": "2026-04-01", "mean": 5.1, "site": "Compton", "units": "Micrograms/cubic meter (LC)", "method": "R & P Model 2025 PM-2.5 Sequential Air Sampler w/VSCC - Gravimetric", "maxHour": 0, "latitude": 33.901389, "standard": "PM25 24-hour 2006", "longitude": -118.205, "siteNumber": "1302", "sampleDuration": "24 HOUR" }, { "aqi": 28, "max": 5.1, "poc": 1, "city": "Compton", "date": "2026-04-01", "mean": 5.1, "site": "Compton", "units": "Micrograms/cubic meter (LC)", "method": "R & P Model 2025 PM-2.5 Sequential Air Sampler w/VSCC - Gravimetric", "maxHour": 0, "latitude": 33.901389, "standard": "PM25 Annual 2006", "longitude": -118.205, "siteNumber": "1302", "sampleDuration": "24 HOUR" } ], "count": 100, "state": "CA", "total": 158, "county": "Los Angeles", "source": "US EPA Air Quality System (aqs.epa.gov)", "checkedAt": "2026-10-23T09:37:09.303Z", "pollutant": "PM2.5", "countyFips": "06037", "parameterCode": "88101" } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/epa-aqs-air-quality-monitor-data-by-county-05aef555/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from api.companyrecords-api.workers.dev](https://www.zero.xyz/host/api.companyrecords-api.workers.dev/llms.txt)