query epa aqs annual pollutant summary statistics using a parameter class
domain: aqs.epa.gov · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Register for an email+key via GET /data/api/signup?email=... (required on every request)
Discover valid parameter class names: GET /data/api/list/classes?email=...&key=... (e.g. CRITERIA, AQI POLLUTANTS, ALL)
Get the parameter codes in a class: GET /data/api/list/parametersByClass?email=...&key=...&pc=CRITERIA
Request annual summaries: GET /data/api/annualData/byState (or byCounty, bySite, byBox, byCBSA) with email, key, param (up to 5 codes), bdate, edate, and a geography filter
Only the year portion of bdate/edate is used for annualData — full calendar-year stats (mean, maxima, percentiles, observation count) are returned
Known gotchas
The pc (parameter class) value is case-sensitive and must be uppercase, e.g. CRITERIA not criteria
annualData still requires bdate/edate even though only the year is used
The same 5-parameter-code limit and request-rate throttle apply as other AQS services
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