Tracking Air Quality

Air quality refers to the degree to which the ambient or outdoor air in our surrounding environment is pollution- free. It is typically measured near ground level, away from direct sources of pollution.

The National Ambient Air Quality Standards (NAAQS) has established standards or limits for six air pollutants, known as the criteria air pollutants:

  • Carbon Monoxide (CO)
  • Lead (Pb)
  • Nitrogen Dioxide (NO2)
  • Ozone (O3)
  • Particulate Matter (PM)
  • Sulfur Dioxide (SO2)

Monitoring Air Quality

Federal, state, local, and tribal air agencies operate and maintain a wide variety of outdoor air monitoring systems across the United States. Many of these systems serve several environmental objectives. At a basic level, they let us know how clean or polluted the air is, help us track progress in reducing air pollution, and inform the public about air quality in their communities through the Air Quality Index (AQI). The AQI is a tool to help you quickly learn when air pollution is likely to reach unhealthy levels.

There are 14 air quality monitoring stations located throughout New Hampshire. View list of air quality monitoring stations.

Health Impacts of Poor Air Quality 


Ozone is created indirectly when nitrogen oxides and volatile organic compounds mix in the presence of heat and sunlight. Your exposure to ozone depends mainly on where you live and work and how much time you spend outside. Everyone can have health problems associated with ozone. Symptoms might be very mild or more serious. People with lung disease, children, older adults, and people who are active outdoors are at the highest risk of having problems when ozone levels are elevated.

Many scientific studies have linked ground-level ozone exposure to varied health problems, such as:

  • Aggravation of asthma, bronchitis, and emphysema;
  • Coughing and pain when taking a deep breath;
  • Higher chance of getting respiratory illness such as pneumonia or bronchitis;
  • Lung and throat irritation; and
  • Wheezing and breathing difficulties during exercise or outdoor activities.

Particulate Matter

Particle pollution, or particulate matter, consists of particles that are in the air, including dust, dirt, soot and smoke, and little drops of liquid. Fine particulates occur from being directly emitted (e.g., from a smokestack or tailpipe) or from secondary reactions in the air (e.g., when water vapor condenses on sulfate ions, which is also a secondary product of combustion). Some particles, such as soot or smoke, are large or dark enough to be seen. Other particles are so small that they cannot be seen by the naked eye. Small particles are the most concerning because they are most likely to cause health problems. Due to their small size these particles can get deep into the lungs.

Being exposed to any kind of particulate matter may cause:

  • Adverse birth outcomes, such as low birth weight;
  • Asthma symptoms to get worse;
  • Breathing problems;
  • Decreased lung growth in children;
  • Early deaths;
  • Increased emergency department visits and hospital stays for breathing and heart problems; and
  • Lung cancer.

Sensitive people, including older adults, people with diseases such as asthma or congestive heart disease, and children, are more likely to be affected by exposure to PM2.5.

Reducing Risk

EPA's Air Quality Index, or AQI, is a tool to help you quickly learn when air pollution is likely to reach unhealthy levels. Local TV stations, radio programs, and newspapers carry these air quality forecasts to tell you when particle levels are likely to be unhealthy.

When particle pollution levels are high, you can:

  • Do easier outdoor activities, such as walking instead of running or using a riding lawn mower instead of a push mower;
  • Exercise away from roads and highways because particle pollution is usually worse in these areas; and
  • Reduce the amount of time you spend outside.