Overall Air Quality
Overall ambient air quality continues to improve. For calendar year 2011, the average annual air Quality index value for Mecklenburg County was 48, which equates to good air quality. From 2002 to 2011 the average annual index has gone from 59 to 48, which equates to an 18.6% improvement in air quality. In 2011 there were 259 good days (71%), 89 moderate days (24.4%), 17 unhealthy days (sensitive and all) (4.6%). The two main pollutants that make up Mecklenburg County's ambient air quality index value are ozone and PM 2.5. See below for an explanation of the air quality index.
Air Quality Index
What is the Air Quality Index (AQI)?
The Air Quality Index (AQI) is a scale of 0-300 that indicates the amount of air pollution that is forecasted or measured and how that affects our health. The higher the AQI value, the greater the amount of air pollution that is present in our outdoor air and the greater the health concern. Colors have been assigned to ranges of AQI values to effectively communicate the health impacts of the air quality. The two pollutants that are commonly represented by this scale in the Charlotte Area are Ground-level Ozone and Particulate Matter (PM).
Annual Air Quality Index (AQI) Designations
What do the colors mean?
When the AQI Color Code is green or yellow, the air quality is considered acceptable and is not expected to have widespread health impacts.
When the AQI value is higher than 100, the air quality has exceeded health-based standards set by the Environmental Protection Agency (EPA). Although the general public may not feel the effects of Code Orange days, sensitive groups may experience negative health impacts. Sensitive groups include people with lung or heart disease, older adults, active people, and children.
When the Color Code is Red or Purple, the general public is likely to experience negative health impacts.
How can I protect my health on bad air quality days?
To protect your respiratory health on Code Orange, Red or Purple days, you should limit prolonged or heavy exertion outdoors, especially in the afternoon hours when air quality is typically worse. Your exposure to air pollution depends on the length of time and level of exertion. Any activity that increases your breathing rate also increases your risk of exposure to air pollution. You don't need to stay indoors, but "take it easy" outdoors to reduce your risk.
How do I get the Air Quality Forecast?
You can get the Air Quality Forecast from the Mecklenburg County Air Quality website. You can also subscribe to email or text notifications at www.enviroflash.info. Check your local TV or newspaper weather report, especially in the summer months.
For more information on this topic, see the links included or go to "Contact Us" on the MCAQ home page.
What you can do to reduce air pollution in Mecklenburg County.
• Mecklenburg County Air Quality Index
• Air Quality Monitoring Sites
• AQI - A Guide to Air Quality and Your Health
• EPA - Air Quality Index
• Stationary Sources
• Mobile Sources
• Area Sources
• Health Effects of Air Pollution
Return to Air Quality Chapter Page
The trends shown in the State of the Environment Report are not all based on tests of statistical significance. Data analysis, anecdotal evidence, and best professional judgment have been compiled to represent these trends. The State of the Environment Report takes a snapshot of important environmental indicators in an effort to educate the public while highlighting challenges, successes and the general direction of change for each indicator. For additional information on these indicators and the determination of trends, please follow the links and feel free to contact the appropriate resources.
Last updated 4/16/12