Air Quality Info

Eight counties in the Charlotte region are designated by the U.S. EPA as a nonattainment area for ground-level ozone: Cabarrus, Gaston, Iredell, Lincoln, Mecklenburg, Rowan, Union and York (SC).

This means that on many days each year, air pollution exceeds healthy levels. It also means that the region could face serious penalties if the air quality isn’t improved.

Ground-level ozone is a secondary pollutant, meaning it doesn’t come directly from a source such as smokestacks or tailpipes. Instead, it is created when two primary pollutants – oxides of nitrogen (NOx) and volatile organic compounds (VOCs) are “cooked” by sunlight and high temperatures. This means that we are most likely to see high ozone levels during the hot spring and summer months, May 1 – September 30 each year. It is estimated that more than 55 percent of ozone air pollution in the nonattainment region is caused by emissions from cars and trucks.

Exposure to high ozone levels is particularly hazardous to children, the elderly, and those with respiratory conditions such as asthma — but it can also cause breathing difficulties and reduced lung function in healthy adults.

Another pollutant of concern is particle pollution. While the Charlotte metro area is not currently designated as a nonattainment area for particle pollution, it is still a concern. Particle pollution causes many of the same health effects as groud-level ozone, but has also been linked to cardiovascular diseases and even mortality. Further, while ozone exceedances are most likely to occur during the hot summer months, particle pollution levels can be high at any time of the year.

The U.S. EPA developed the Air Quality Index as a tool for reporting air quality levels to the public. Information about regional air quality and the AQI is available from North Carolina Air Awareness, where residents, employers and other interested organizations can sign up to receive daily Air Quality forecast emails.

For additional information and resources related to air quality, visit the Mecklenburg County Air Quality homepage.

A New, Tougher Air Quality Standard for Ozone: In January 2010, the EPA proposed to strengthen the standard for ground-level ozone. The proposed revision is based on scientific evidence about ozone and its effects on people and the environment. EPA proposes to strengthen the 8-hour “primary” ozone standard, designed to protect public health, to a level within the range of 0.060 – 0.070 parts per million (ppm). The below chart shows our ozone levels relative to the passed and proposed National Ambient Air Quality Standards (NAAQS).

Ozone NAAQS Compliance Values – Mecklenburg County Air Quality

EPA will finalize the new standard at the end of August 2010. What does this mean for the Charlotte region? We were in nonattainment of the 1997 and 2008 standards, and the new standard will be even tougher because of the potential negative health effects. That is why employers’ efforts through Clean Air Works! and other initiatives are so important.

For more information about the new standard, visit EPA’s website.