Air Quality Guidance

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The ozone maps available as air quality forecasting guidance products represent concentrations of forecasted ground-level ozone. The guidance is used by state and local air quality forecasters to assist them in issuing Air Quality Index (AQI) forecasts. The AQI links air quality-- in this case, for ozone concentrations-- to health effects and cautionary language or interpretive guidance for individuals.

When ozone is the only pollutant affecting air quality, the risks to people's health can be described from both short-term exposure to ozone (based on 1-hr averaged concentrations) and longer-term exposure to ozone (based on 8-hr average concentrations). EPA developed the following scale that relates shorter and longer-term exposure to the ambient ozone concentrations, in parts per billion (ppb), to health risk.

Air Quality Index Concentration Chart

Information on local AQI forecasts and current AQI levels can be found at Access to the air quality model guidance in AQI format can be found at

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Element Definitions:
1Hr Ozone Concentration
8Hr Ozone Concentration
1Hr Average Surface Smoke
1HrAverage Vertical Smoke Integration

A Color Blindness Tool can be accessed by clicking here.