The South Coast Air Quality Management District (South Coast AQMD) has led the development of a modified version of the Air Quality Index (AQI) that will provide better accessibility for those with color vision deficiencies. The changes were primarily made to the hues, keeping the essential colors associated with each AQI category and health impacts (green, yellow, orange, red, purple, maroon). The original color scale can be difficult to discern for those individuals who have challenges distinguishing certain colors, especially red and green.
“This is an important step to make our air quality measurements and recommendations accessible to even more residents,” said Wayne Nastri, South Coast AQMD’s Executive Officer. “Since the AQI is associated with important health recommendations, it is our goal to make all the information that we provide to the public as accessible and easy to use.”
Colors on the AQI are associated with important recommendations to help the public minimize their exposure to poor air quality. The modified color scale will accommodate individuals with color vision deficiencies, while still being similar enough to the traditional AQI color scale that has been used for decades. The modified scale was tested against eight common types of color impairments using a simulator to ensure the categories would be distinguishable. Another key feature is that the new scale moves from the lightest color (green) to the darkest color (maroon) so that it can be interpreted when converted to grayscale.
The new color scale also works as a continuous gradient, which will improve AQI animations and visualizations from air pollution events such as smoke from a wildfire. Currently the modified AQI is being piloted on several applications including the U.S. Environmental Protection Agency’s (U.S. EPA) Fire and Smoke map at https://fire.airnow.gov/ as well as South Coast AQMD’s real-time air quality map at www.aqmd.gov.