Who Issues the Daily Air Quality Report, and Where Does the Data Come From?

The short answer

The daily report on pollution levels in the United States is the Air Quality Index (AQI), developed by the U.S. Environmental Protection Agency and published to the public through AirNow, a partnership of the EPA, the National Oceanic and Atmospheric Administration, and state, local, and tribal air agencies. AirNow's AQI basics page explains the index itself; this page is about the machinery behind it — who actually produces the number you see each day, and where you can inspect the raw material.

The chain from smokestack to smartphone

A daily AQI report is the last step in a pipeline with several distinct actors:

• Monitoring agencies. State, local, and tribal environmental agencies operate networks of regulatory-grade outdoor monitors, sited and maintained to federal specifications. These instruments measure concentrations of the criteria pollutants — ozone, particle pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide — continuously, not just once a day.
• The EPA. The agency sets the monitoring requirements, defines the AQI methodology (the conversion from concentrations to index values), and aggregates the data nationally. The complete record of measurements, current and historical, is public through the EPA's outdoor air quality data portal.
• AirNow. This is the reporting and forecasting layer: it collects near-real-time data from the participating agencies, computes current AQI values, and hosts the daily forecasts that local forecasters issue for their own areas.
• The National Weather Service. NWS partners with air agencies on air quality forecasting and disseminates air quality alerts alongside its weather products; its air quality safety page explains that role.

So when a weather app, a TV meteorologist, and a newspaper all report the same AQI for your city, they are usually drawing on the same upstream federal-state pipeline, not measuring anything themselves.

Forecasts vs. observations

Each day's reporting actually contains two different products, and it helps to keep them straight:

• The daily AQI forecast is issued by local air agency forecasters — a prediction of the peak index value expected, usually for today and tomorrow, often naming the pollutant expected to drive it.
• The observed AQI is calculated from what the monitors actually recorded. Current conditions use a real-time estimation method; the final daily value uses the full averaging period for each pollutant. Our guide on how the AQI is calculated covers that arithmetic.

A forecast that misses is not a malfunction; it is a forecast. Wind shifts and fire behavior move pollution in ways that are genuinely hard to predict a day ahead.

Looking up past air quality yourself

One underused fact about this system: the underlying data is public. Through the EPA's AirData portal you can pull daily AQI values for a county going back years, see which monitor produced a reading, which pollutant was primary on a given day, and download the raw concentration data. Practical uses include:

• Checking what the air was actually like on a specific past date — for example, during a smoke event — rather than relying on memory.
• Comparing two counties or two years using the same official yardstick.
• Finding out which pollutants are monitored near you, since not every location measures every pollutant, and that shapes what your local AQI can reflect.

What about low-cost sensors and crowdsourced maps?

Consumer air sensors and crowdsourced maps have made neighborhood-level readings ubiquitous, and they can be genuinely informative about local conditions and trends. But they are not part of the regulatory pipeline: the official daily report, and any legal determination about whether an area meets the national standards, rests on the regulatory monitor network. When a consumer sensor and the official reading disagree, you are looking at different instruments, different siting, and different quality-assurance rules — not necessarily an error on either side. For interpreting the official number once you have it, see how to read the AQI.