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My Health & Environment - Environmental Public Health Tracking

Air Quality

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The Environmental Protection Agency (EPA) is responsible for setting National Ambient Air Quality Standards (NAAQS) for pollutants considered harmful to public health and the environment. Currently there are six principal pollutants for which there are NAAQS and are often referred to as the criteria pollutants.

Of the six criteria pollutants, ground-level ozone and particle pollution pose the most widespread health threats, but they all have the potential to cause damage to human health and the environment. The Department of Health and Environmental Control’s Bureau of Air Quality maintains a monitoring network for all criteria pollutants, and provides this information to the public and the EPHT program.

Ground-level Ozone or Ozone

What is Ozone?

ozone forecast image

Ozone is a gas made up of three oxygen molecules. The good ozone, known as the ozone layer, is up higher in the atmosphere and protects us from the suns harmful rays. Ground-level ozone is a type of air pollution that is near the earths surface and forms on hot sunny days when nitrogen oxides and volatile organic compounds (VOCs) react.

Where does Ground-level Ozone come from?

Nitrogen oxides and VOCs that come from vehicles, smokestacks, and natural sources, react to the sun's heat and form ground-level ozone. In South Carolina, pollution from mobile sources accounts for the majority of air pollution.

How can exposure to Ozone affect me?

Everyone has some sensitivity to ground-level ozone. You can be exposed to ozone by breathing in air that contains ozone. Exposure to ozone can irritate your respiratory system, cause shortness of breath, wheezing, coughing and worsen asthma and bronchitis.

Where can I find information on daily Ground-level Ozone concentrations?

Air pollution levels can vary throughout the day for ground-level ozone. Become familiar with the Ozone Forecast for South Carolina to adjust your day accordingly, reduce your exposure, and reduce your impact on air quality. You can also sign up to receive the daily Ozone Forecast, via EnviroFlash.

Particulate Matter or Particle Pollution

NOTE: Currently, S.C. DHEC does not forecast for Particulate Matter (PM) because South Carolina is in compliance with the annual and 24 hour PM standards. The EPA regulates inhalable particles (fine and coarse). Particles larger than 10 microns (sand and large dust) are not regulated by the EPA.

What is Particulate Matter?

Particulate Matter (PM) is made of solid particles and liquid droplets that are in the air. There are many sources and sizes of particles in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small; they can only be detected using an electron microscope.

Currently there are two standards for Particulate Matter, PM10 and PM2.5. Both have their own annual and 24-hour standards. PM10 refers to particles with a diameter of 10 microns. One thousand particles of this size could fit into a period at the end of this sentence. PM10 also referred to as “coarse particulate” is composed largely of primary particles.

PM2.5 is referred to particles that have a diameter of 2.5 microns or less. In comparison, human hair has a diameter of 70 microns. PM2.5 also referred to as “fine particulate” is composed mostly of secondary particles.

Where does Particulate Matter come from?

Primary particles (PM10) come from a wide variety of stationary, mobile, and natural sources such as construction sites, power production, diesel trucks, smokestacks, and forest fires. These coarse dust particles range in size from 2.5 to 10 microns in diameter.

Secondary particles (PM2.5) come from the same sources as PM10 the chemical composition of particles depends on location, time of year, and weather. Secondary particles make up most of the fine particle pollution in the country.

How can exposure to Particulate Matter affect me?

Particulate Matter can enter the body through inhalation and accumulate in the respiratory system. The size of particles is directly linked to their potential for causing health problems.

Exposure to coarse particles (PM10) is primarily associated with the aggravation of respiratory conditions, such as asthma.

Fine particles (PM2.5) are most closely associated with health effects such as increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory disease and symptoms such as decreased lung function, and even premature death.

Particulate Matter is also the major cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas.


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Air Quality Resources and Materials

What can I do to protect myself from Ground-level Ozone?

  • Know the ground-level ozone forecast
  • During ozone season (April 1st to September 30th), do outside activities in the morning.
  • Dont stay outside too long during the hottest part of the day.
  • Limit exercise exertion and working outside on high ozone days.

What can I do to help reduce Ground-level Ozone?

Using the latest forecasting tools, high ozone days (or Ozone Action Days), can be predicted.
Receive the ozone forecast (EPA-AirNow) and adjust your schedule accordingly.

  • Drive Less
  • Carpool, vanpool, walk, or ride a bike
  • Shop by phone, mail, or the Internet
  • Combine your errands into one trip, "trip-chain"
  • Telecommute or work flex hours

What can I do to protect myself from Particulate Matter (Particle Pollution)?

  • Avoid dusty areas
  • Dont exercise near busy roads
  • Avoid smoky areas

What can I do to help reduce Particulate Matter?

EPA’s national and regional rules to reduce emissions of pollutants that form particle pollution will help state and local governments meet the Agency’s national air quality standards.

  • Save energy and use clean, renewable resources.
  • Keep car, boat and other engines properly tuned, and avoid engines that smoke.
  • Consider using gas logs instead of wood. Burn only dry, seasoned wood.
  • Mulch or compost leaves and yard waste instead of burning it.
  • Avoid using gas-powered lawn and garden equipment.

Additional Programs

Do your part to help reduce Air Pollution, Ground-level Ozone, and Particulate Matter.

you hold the key image You Hold the Key SC
Reduce your vehicle miles traveled (VMT) and mobile source emissions.
breath better image B2 (Breathe Better)
An anti-idling/clean air campaign to reduce harmful vehicle emissions around school campuses.
Lawn mower exchange image Lawn Mower Exchange
Trade in your gas-powered mower for a cordless electric mower at a discounted price.
open burning image Open Burning
An awareness campaign to encourage citizens to consider alternatives to open burning.
Champions of the Environment Champions of the Environment
Rewards K-12th grade students and teachers for environmental projects.
All Health Team All-Health Team
Rewards youths and their leaders for promoting healthy eating and being active.

Related Resources

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Air Quality Maps

See our new Dynamic Portal to view Air Quality Maps

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Air Quality Data

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For more detailed Air Monitoring Data, see the South Carolina Air Monitoring Network provided by the DHEC Bureau of Air.

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  • NAAQS - National Ambient Air Quality Standards.  These are limits set by the Environmental Protection Agency (EPA) for pollutants that are considered to be hazardous to public health and to the environment.  There are six criteria pollutants for which these limits have been established:  Particulate Matter with diameter of ten (10) microns (PM10) or 2.5 microns (PM2.5), Carbon Monoxide (CO), Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3) and Lead (Pb).
  • Ozone Standard - The ozone National Ambient Air Quality Standard (NAAQS) is comprised of a primary standard to protect health and a secondary standard to protect sensitive plants and animals. The EPA revised both 8-hour ground level ozone standards to a level of 0.075 parts per million (ppm). To meet the ozone standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.075 ppm.
  • PM2.5 Standard - The PM2.5 NAAQS is comprised of a primary standard to protect health and a secondary standard to protect public welfare, including protection against visibility impairment, damage to animals, crops, vegetation and buildings. There are two averaging times for the PM2.5 NAAQS.  The annual standard measures chronic exposures to PM2.5 while the 24-hour standard measures acute (or short-term) exposures.  The EPA has set both PM2.5 standards to a level of 12.0 micrograms per cubic meter (µg/m3) for the annual averaging time and 35 µg/m3 for the 24-hour averaging time. To meet the annual PM2.5standard, the 3-year average of the weighted annual mean PM2.5 concentrations from single or multiple community-oriented monitors must not exceed 12.0 µg/m3.  To meet the 24-hour PM2.5 standard, the 3-year average of the 98th percentile of 24-hour concentrations at each population-oriented monitor within an area must not exceed 35 µg/m3.

Related Resources

DHEC Resources

Other Resources


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For additional information, contact the SC EPHT program:
These web pages are supported by Cooperative Agreement Number 5U38EH000628-02 from The Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.