Nitrogen Oxide (NOx)
Nitrogen dioxide (NO2
) is one of a group of highly reactive gases known as nitrogen oxides (NO2
). While the Environmental Protection Agency's National Ambient Air Quality Standards (NAAQS)
covers the entire NOx group, NO2
is the component of greatest interest and the indicator for the larger group of nitrogen oxides. NO2
forms quickly from emissions from cars, trucks and buses, fossil fuel-fired power plants and off-road equipment. NO2
is a key precursor to ozone formation.
The NAAQS for NO2
is a primary 1-hour standard of 100 ppb. Mecklenburg County meets the current NO2
Sulfur Dioxide (SO2)
Sulfur dioxide (SO2
) is one of a group of highly reactive gases known as "oxides of sulfur." It is produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores (aluminum, copper, zinc, lead and iron) that contain sulfur.
The NAAQS for SO2
is a 1-hour standards of 75 ppb and a 3-hour standard of 0.5 ppm. Mecklenburg County meets the current SO2
Carbon Monoxide (CO)
Carbon Monoxide (CO) is a colorless, odorless gas that is formed when carbon in fuel is not burned completely. CO is a component of motor vehicle exhaust. Higher levels of CO generally occur in areas with heavy traffic congestion. In Mecklenburg County, the majority of all CO emissions come from motor vehicle exhaust.
The NAAQS for CO consist of a primary 8-hour standard at 9 ppm and a 1-hour primary standard at 35 ppm. Mecklenburg County meets the current CO standards.
Lead is a metal found naturally in the environment as well as in manufactured products. The highest levels of lead concentrations are usually found near lead smelters. Other stationary sources that produce lead emissions are waste incinerators, utilities and lead-acid battery manufacturers. With almost no known lead sources, Mecklenburg County has not routinely conducted lead monitoring. On December 14, 2010, EPA revised the ambient monitoring requirements for lead which resulted in MCAQ implementing a lead monitoring network in 2011 to determine compliance with the revised NAAQS.
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 - Criteria Pollutants
• Stationary Sources
• Mobile Sources
• Area Sources
• Health Effects of Air Pollution
• EPA - NOx Overview
• Health Effects of Nitrogen Oxides
• NCDENR - Sulfur Dioxide
• Health Effects of Sulfur Dioxide
• EPA - Mobile Sources - Carbon Monoxide
• Health Effects of Carbon Monoxide
• EPA - Lead Standards
• Health Effects of Lead in Air
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