Reference · built on requestCommons signalAir, water & environment

EPA Air Quality System (AQS) Data API

Quality-assured US ambient air monitoring data from EPA's Air Quality System, as JSON, months after collection.

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About

The Air Quality System is EPA's repository of ambient air quality data, submitted by EPA, state, local, and tribal air pollution control agencies. It holds pollutant measurements, meteorological data, monitor descriptions with location and operator, and quality assurance records. The Data API at aqs.epa.gov/data/api returns this as JSON. AQS is not a real-time source; EPA notes it can take six months or more for collected data to appear.

An operator on Fibric uses it for the settled record: annual and daily summaries by site, county, or CBSA, to benchmark a location or back up a compliance figure.

This is a reference listing. It documents what Fibric would read from EPA Air Quality System (AQS) Data API and what it could propose, based on the publisher's published interfaces. Fibric builds it under a managed deployment when you request it; selecting it here installs nothing.

Inputs

  • Hourly and finer samples through sampleData/bySite, byCounty, byState, byBox, and byCBSA
  • Midnight-to-midnight local summaries through dailyData and calendar summaries through quarterlyData and annualData
  • Monitor and sampling equipment records through the monitors service
  • Valid codes through list/states, list/countiesByState, list/sitesByCounty, list/classes, and list/parametersByClass
  • Quality assurance data: blanks, collocated assessments, flow rate audits, and one-point QC checks
  • Change-date filtering with cbdate and cedate to pick up rows edited since a date

Proposed actions

Read-only. This feed informs operators; it changes nothing.

Proposed actions are target capabilities. Every action runs propose-first and needs a validated deployment and the appropriate permissions.

What you can build

  • Benchmark sites on settled annual data

    Pull annualData for the counties around each site and rank them on PM2.5 and ozone. The operator writes the comparison and cites the parameter codes and year.

    With Site Benchmark

  • Back a compliance figure with the public record

    When a report cites local air quality, attach the AQS daily summary that supports it so a reviewer can fetch the same rows.

    With Compliance Evidence

  • Flag when the record stops updating

    Track the latest available date per site and raise a notice when the lag grows beyond what you expect, so nobody mistakes an old summary for a fresh one.

    With Data Freshness

Requirements

  • A registered email and the key sent from aqsdatamart@epa.gov
  • Five-digit AQS parameter codes, up to five per request, and a geographic filter
  • bdate and edate in YYYYMMDD within the same calendar year
  • Pacing on your side: no more than 10 requests per minute with a 5-second pause between them
Authentication
A free API key issued by email through https://aqs.epa.gov/data/api/signup; every request carries email and key as query parameters.

Limits

  • Data lag collection by six months or more; the API is not for current conditions
  • One calendar year per request for all services except Monitors
  • EPA recommends staying under 1,000,000 rows per query and can suspend accounts that ignore the limits
  • JSON only; no CSV, streaming, or webhook delivery

Access and pricing

Reference listing. Public feed access is separate from Fibric integration. If you request this feed, your quote covers the build, usage, and support.

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Questions and answers

Can you use the AQS API for today's air quality?
No. EPA states that AQS does not contain real-time data and that it can take six months or more from collection until data appears. For current readings, use a near-real-time source and keep AQS for the settled record.
What are the request limits?
Up to five parameter codes per request, begin and end dates in the same year, no more than 10 requests per minute, a 5-second pause between requests, and a recommended ceiling of 1,000,000 rows. EPA may suspend accounts without notice for violations.
How do you get a key?
Send a request to the signup endpoint with your email address. EPA emails a key from aqsdatamart@epa.gov. The same endpoint resets an existing key. The key identifies your account; it is not a password.
Ask about EPA Air Quality System (AQS) Data API

Ask about the capabilities and requirements in this listing.

For project-specific requirements, contact Fibric.

This Commons signal listing is developed, published, and supported by Fibric. It reads public data published by U.S. Environmental Protection Agency (aqs.epa.gov). Upstream agencies and projects are the property of their respective owners, who are not affiliated with Fibric and do not sponsor or endorse this listing. Trademark policy