EPANext-day AQI forecasts for ozone and PM2.5 issued by state and local air quality agencies across the United States, published daily through the AirNow forecast system.
EPA
AQS / AirNow Air Quality Monitoring Data
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NASA
The Air Quality System (AQS) is EPA's primary repository of ambient air quality data, collecting measurements from more than 10,000 monitoring stations across the United States, Puerto Rico, and the U.S. Virgin Islands. The network captures PM2.5, ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, and lead concentrations at hourly and sub-hourly intervals.
AirNow delivers real-time Air Quality Index data to the public through interactive maps, mobile apps, and data feeds. Measurements are integrated with IMPROVE (Interagency Monitoring of Protected Visual Environments) and CASTNet (Clean Air Status and Trends Network) to provide comprehensive ground-truth for satellite retrievals and model validation.
Learn more
Documentation, algorithm details, and background reading for AQS / AirNow.
Download data
Access AQS / AirNow through the provider portal or download it directly.
Tutorials
Self-paced tutorials to help you get started with AQS / AirNow.
Getting started with AQS / AirNow
An introduction to the AQS / AirNow dataset — what it measures, how it is produced, and when to use it.
Accessing and downloading AQS / AirNow dataFind, subset, and download AQS / AirNow data, with tips for common file formats and access tools.
Exploring AQS / AirNow in the AIR4US visualization toolLoad AQS / AirNow layers in the AIR4US visualization tool and interpret them alongside other air quality data.
Cite this dataset
US EPA. AQS / AirNow Air Quality Monitoring Data. 1980 – Present. Accessed via the AIR4US Portal, https://www.airnow.gov.
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