Air Quality Indicator
- Unhealthy Air Quality Days
Introduction
Although our earth's "ozone layer" (atmospheric ozone located
10-30 miles above the Earth's surface) protects us from the sun's harmful
ultraviolet rays, ozone at ground level is a health hazard. Ground level
ozone is a gas created by volatile organic compounds (VOCs), oxides of
nitrogen (NOx ) and sunlight. Cars, power plants, industrial boilers,
refineries, chemical plants and other sources emit VOC and NOx. Sunlight
"cooks' VOC and NOx, creating ground level ozone. Ground level ozone
can irritate respiratory systems, impair ability to breathe, aggravate
asthma, and inflame and damage the linings of lungs. Scientists are researching
long-term effects and have concerns that developing lungs of children
repeatedly exposed to high levels of ozone may be damaged.
Cars and other vehicles are the largest single source for ozone problems. While Gaston County has little control over vehicle use in other counties in the region, it can manage growth in ways to locate residences closer to and among employment centers, and encourage carpooling and alternate sources of transportation. Public education about how to reduce ground level ozone is encouraged. As the region continues to grow, these efforts will be required on a regional basis to prevent an increase in ozone exceedances. The American Lung Association's 2003 State of the Air Report identified the Charlotte-Gastonia-Rock Hill metropolitan area as the 10th smoggiest metro area in the United States. The Greensboro area (17th) and Raleigh area (22nd) were also identified in the top twenty-five smoggiest metropolitan areas in the United States.
Air Quality Indicator: Unhealthy Air Quality Days
About the Indicator
Ozone is primarily a hot weather problem, with most high readings occurring
in June, July, and August. The NC Division of Air Quality (DAQ) maintains
monitors across the state. The Clean Air Act designates the national air
quality ozone standard as 0.08 parts per million (ppm) over an eight hour
period. This is one standard method of measuring air quality in urban
areas. Since air and the pollutants in it travel with no mind to jurisdictional
boundaries, air quality is measured on a regional basis. Gaston County
falls within the Charlotte local network. The Charlotte local network
includes Mecklenburg, Gaston, Lincoln, Cabarrus, Rowan, Union, York (S.C.)
and the Southern third of Iredell counties.
Unhealthy conditions are reached when any one of the eight monitoring stations in the region exceeds the EPA 8-hour ozone standard. Conditions are also measured by a color code. When standards exceed the EPA ozone standard, a code orange air quality notice is issued by The North Carolina Division of Air Quality. Red and purple codes identify worse air quality conditions.
The color-coded Air Quality Index (AQI) used by the NC DAQ to warn citizens
of unhealthy air quality is illustrated below.
| Air Quality | Air Quality Index | Health Effects |
| Good (green) | 0-50 | None expected |
| Moderate (yellow) | 51-100 | Unusually sensitive people should consider limiting prolonged outdoor exertion |
| Unhealthy for sensitive groups (orange) | 101-105 | Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion |
| Unhealthy (red) | 151-200 | Everyone, especially children, should limit prolonged outdoor exertion |
| Very unhealthy (purple) | 201-300 | Everyone, especially children, should avoid all outdoor exertion |
Over the past six years, the Charlotte-Gastonia-Rock Hill metropolitan area has experienced an average of 35 days per year of unhealthy air. These unhealthy air days include orange, red, or purple coded days.
QNRC's Goals and Recommended Actions
| Indicator | 2008 Goal | Actions to achieve the goal |
| Number of unhealthy air quality days |
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