Air pollution is made up of many kinds of gases, liquid droplets and particles.
In the city, cars, buses and airplanes, as well as industry and construction cause air pollution. In the country, smoke from wood and crop fires, dust from tractors plowing fields, and dust from traffic on dirt roads cause air pollution.
Ozone: What is it?
Ground-level ozone is the major component of air pollution in many cities. In the city, pollutants that are already in the air from cars and trucks react with sunlight to form ground-level ozone.
Ground-level ozone should not be confused with the “good” ozone that is miles up in Earth’s stratosphere and that protects us from the sun’s harmful radiation.
Ground-level ozone (smog) is formed by a chemical reaction between volatile organic pollutants (VOCs) and oxides of nitrogen (NOx) in the presence of sunlight. Ozone concentrations can reach unhealthy levels when the weather is hot and sunny with little or no wind. Ozone at the ground level causes adverse effects on lung function. It is one of the six “criteria” pollutants for which EPA has adopted National Ambient Air Quality Standards.
Ground-level ozone in the Research Triangle Region
8 counties in the Research Triangle Region, as well as other areas of North Carolina, were designated nonattainment for the ground-level ozone standard in April 2004. Nonattainment means that our air quality monitors have shown that our air has more than the acceptable limit of this pollutant.
These 8 counties* now hold 8-hour ozone maintenance status, meaning ozone measurements averaged over an 8-hour monitoring period are below the ozone limits. By the end of July 2011, EPA will announce strengthened ozone standards, which means maintenance counties could potentially revert to nonattainment status.
*The 8 counties within the Research Triangle Region who are currently designated as maintenance for 8-hour ozone levels are:
- Chatham County (Baldwin, Center, New Hope and Williams Townships)
- Durham County
- Franklin County
- Granville County
- Johnston County
- Orange County
- Person County
- Wake County
Carbon Monoxide
What is it?
A colorless, odorless, poisonous gas, produced by incomplete burning of carbon-based fuels. including gasoline, oil and wood. Carbon monoxide is also produced from incomplete combustion of many natural and synthetic products. For instance, cigarette smoke contains carbon monoxide. When carbon monoxide gets into the body, the carbon monoxide combines with chemicals in the blood and prevents the blood from bringing oxygen to cells, tissues and organs.
Carbon Monoxide in the Triangle
The Triangle has been in attainment of USEPA’s health-based standard for CO since 1995. (Attainment means that our air quality monitors have shown that our air has less than the acceptable limit of this pollutant.)
Find out more …
How carbon monoxide affects the way we live and breathe
Protect you and your family from carbon monoxide
Carbon Monoxide Maintenance areas in NC
Particulate Matter
What are they?
“Particulate matter” is the term used to describe dust, soot, smoke and liquid droplets directly emitted into the air by transportation sources, factories, power plants, construction activity, fires and windblown dust. Secondary Particulate Matter (nitrates and sulfates) are formed from gases by atmospheric processes. PM 10 (coarse) and PM 2.5 (fine) are subgroups referring to the particle diameter size limits in microns. PM 2.5 is considered to be more dangerous than PM10 because finer particles penetrate deeper into the lungs.
Particulate Matter in North Carolina
North Carolina has three counties that are nonattainment for fine Particulate Matter (PM 2.5). The Triangle is not one of these problem areas.
Find out more …
National Emissions Inventory Database
National Particulate Matter Emissions Inventory (Mobile)
How particulate matter affects the way we live & breathe
The nature and sources of particulate matter
Fine Particulate (PM 2.5) Nonattaiment areas in NC
Nitrogen Oxides
What is it?
Nitrogen Oxides are the result of photochemical reactions of nitric oxide in ambient air and major component of urban smog. The primary manmade sources of NOx are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels.
Nitrogen Oxide in the Triangle
Currently, there are no nitrogen oxide nonattainment areas in NC.
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How nitrogen oxide affects the way we live & breathe
Sulfur Dioxide
What is it?
SOx gases are formed when fuel containing sulfur, such as coal and oil, is burned, and when gasoline is extracted from oil, or metals are extracted from ore. SO2 dissolves in water vapor to form acid, and interacts with other gases and particles in the air to form sulfates and other products that can be harmful to people and their environment.
Over 65% of SO2 released to the air, or more than 13 million tons per year, comes from electric utilities, especially those that burn coal.
Sulfur Dioxide in North Carolina
Currently, there are no sulfur dioxide nonattainment areas in North Carolina.
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How SO2 affects the way we live & breathe
Lead
What is it?
Lead is a metal found naturally in the environment as well as in manufactured products. The major sources of lead emissions have historically been motor vehicles (such as cars and trucks) and industrial sources. Due to the phase out of leaded gasoline, metals processing is the major source of lead emissions to the air today. The highest levels of lead in air are generally found near lead smelters. Other stationary sources are waste incinerators, utilities, and lead-acid battery manufacturers.
Lead in the Triangle
The United States has not had problems with lead in the air since about 1977 when USEPA mandated severely reduced levels of lead in gasoline.
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How lead affects the way we live & breathe
USEPA requires low lead gasoline (press release from 1973)
Mercury
Mercury is a naturally occurring element that is found in air, water and soil. It has traditionally been used to make products like thermometers, switches, and some light bulbs. Coal-burning power plants are the largest human-caused source of mercury emissions to the air in the United States, accounting for over 40 percent of all domestic human-caused mercury emissions.
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