EPAReal-time and historical ground-level air quality measurements from EPA's nationwide monitoring network. Incorporates PM2.5, ozone, CO, and NO₂ with IMPROVE and CASTNet quality flags.
EPA
EPA Air Quality Index Forecast
Back to Data CatalogEPA
NASA
NOAA
The AirNow Forecast System aggregates next-day Air Quality Index (AQI) forecasts for ozone and PM2.5 issued by over 400 state, local, and tribal air quality agencies across the United States. Forecasts are produced using a combination of photochemical models, statistical methods, and forecaster judgment.
AQI forecasts are published daily for more than 400 cities and are accessible via the AirNow API, interactive maps, and fire and smoke maps. The system serves as the primary public-facing air quality warning product in the US and is used to trigger action days and health advisories.
Learn more
Documentation, algorithm details, and background reading for AQI Forecast.
Download data
Access AQI Forecast through the provider portal or download it directly.
Tutorials
Self-paced tutorials to help you get started with AQI Forecast.
Getting started with AQI Forecast
An introduction to the AQI Forecast dataset — what it measures, how it is produced, and when to use it.
Accessing and downloading AQI Forecast dataFind, subset, and download AQI Forecast data, with tips for common file formats and access tools.
Exploring AQI Forecast in the AIR4US visualization toolLoad AQI Forecast layers in the AIR4US visualization tool and interpret them alongside other air quality data.
Cite this dataset
US EPA / State Agencies. EPA Air Quality Index Forecast. 2000 – Present. Accessed via the AIR4US Portal, https://www.airnow.gov/aqi/aqi-basics.
Related datasets
Other datasets in the catalog you can explore in the AIR4US visualization tool.
EPANASANASA's global atmospheric reanalysis providing consistent long-term records of aerosol composition, PM2.5, and trace gases from 1980 to present at 0.5° × 0.625° resolution.
NOAAHybrid Single-Particle Lagrangian Integrated Trajectory model for computing forward and backward air parcel trajectories to trace pollution transport pathways.