Understand Air Quality Index colors

-A A +A

From staff reports

Almost every day this time of year, a local meteorologist will emphasize the Air Quality Index (AQI) as part of the upcoming weather forecast, but few know what it means.

The Air Quality Index is the system used to warn the public when air pollution reaches dangerous levels. It tracks ozone (smog) and particle pollution (tiny particles from ash, vehicle exhaust, soil dust, pollen and other air pollutants).

The S.C. Department of Health and Environmental Control warned Midlands residents (Kershaw, Lexington and Richland counties) Wednesday to limit time outside due to high ground-level ozone concentrations.   

Keeping track of air quality information can help you take steps to protect yourself, children, and others from unhealthy air pollution levels. This includes people with asthma and other lung diseases, anyone over age 65, those who exercise and work outside or has diabetes or cardiovascular diseases such as high blood pressure, or has suffered a heart attack or stroke.

How the AQI works

Each day, air pollution levels are measure in 900 counties across the nation. They are then ranked on a scale from “0” for perfect air to “500” for air pollution levels that pose an immediate public danger.

The Air Quality Index then breaks air pollution levels into six categories,  each of which has a name, a color and advice to go with each color.

– 0 to 50 (green) is good and no advisory in needed.

– 51 to 100 (yellow) is moderate. On moderate days, unusually sensitive individuals should consider limiting prolonged outdoor exertion.

– 101 to 150 (orange) is unhealthy for sensitive groups. Children, active adults and people with respiratory conditions such as asthma should limit prolonged outdoor activities.

– 151 to 200 (red) is unhealthy. Children, active adults and people with respiratory conditions should avoid prolonged outdoor activities and should limit outdoor exertion.

– 201 to 300 (purple) is very unhealthy. On purple AQI days, children, active adults and people with respiratory conditions should avoid outdoor activities; everyone else should limit outdoor exertion.

– 301 to 500 (maroon) is hazardous. All physical outdoor activities should be avoided on these days.

On day’s Air Quality Index level is orange or worse, the American Lung Association urges you to adjust outdoor plans to avoid vigorous prolonged activities. The adverse health effects of pollution increase with extended periods of exposure and by deep, rapid breathing that accompanies exercise. When possible, stay away from high traffic areas.

While most local weather forecasts include the AQI each day, it is also available through the SCDHEC website, www.scdhec.gov. Click on the “Environment” prompt and look for  “Today’s Ozone Forecast” on the right side of the page. Lancaster County is part of the Catawba District, which also includes Chester and York counties.