Air Quality Forecast
Predictions of future AQI levels issued by state and local agencies, typically covering 1-2 days ahead.
Detailed Explanation
Air quality forecasts are predictions of pollutant concentrations and AQI values for the near future, typically covering the current day and the next one or two days. These forecasts are produced by state and local air quality agencies using a combination of meteorological models, historical patterns, satellite data, and ground-level monitoring data. Forecast accuracy varies by pollutant and season, ozone forecasts tend to be more reliable because ozone formation follows predictable temperature and sunlight patterns, while PM2.5 forecasts are more challenging because wildfire smoke and other events can cause rapid, unpredictable spikes. The EPA's AirNow system (airnow.gov) aggregates forecasts from agencies across the country and provides real-time AQI maps and forecasts to the public. Many cities and states issue Air Quality Action Days when forecasts predict AQI will reach "Unhealthy for Sensitive Groups" or higher, triggering public advisories and sometimes voluntary or mandatory emission reduction measures. AirHistory complements daily forecasts by providing the long-term historical context, knowing your city's 10-year trend, typical seasonal patterns, and dominant pollutant helps you interpret daily forecasts and understand whether a given reading is unusual or part of a chronic pattern. While AirHistory does not provide real-time or forecast data, its historical analysis helps contextualize the daily readings available from AirNow and local agencies.
Related Terms
Air Quality Index (AQI)
A standardized EPA scale from 0 to 500 that communicates daily air quality and associated health risks.
AQI Categories
The six color-coded health concern levels, Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous, used by the EPA to describe air quality.
Unhealthy Air Days
Days when the AQI exceeds 100, meaning air quality may pose health risks for sensitive groups or the general population.
Wildfire Smoke
Airborne particulate matter and gases produced by wildfires, now the leading source of hazardous air quality events in the western United States.
Frequently Asked Questions
Predictions of future AQI levels issued by state and local agencies, typically covering 1-2 days ahead.
Air quality forecasts are predictions of pollutant concentrations and AQI values for the near future, typically covering the current day and the next one or two days. These forecasts are produced by state and local air quality agencies using a combination of meteorological models, historical patterns, satellite data, and ground-level monitoring data. Forecast accuracy varies by pollutant and season, ozone forecasts tend to be more reliable because ozone formation follows predictable temperature and sunlight patterns, while PM2.5 forecasts are more challenging because wildfire smoke and other events can cause rapid, unpredictable spikes.
this entity is one of the U.S. air quality and pollution monitoring concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the the EPA Air Quality System (AQS) data behind every per-entity page on the site.
In the the EPA Air Quality System (AQS) data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.