Particulate Matter, also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.
The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller (less than 1/4th the size of a single grain of table salt) because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. EPA groups particle pollution into two categories:
- "Inhalable coarse particles," such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.
- "Fine particles," such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller (less than 1/30th) the diameter of a human hair). These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.
The current 24-hour PM2.5 standard is 35 micrograms per cubic meter (µg/m³) and the annual PM2.5 standard is 12.0 µg/m³. The existing national 24-hour PM10 standard is 150 µg/m³. Mecklenburg County is currently in compliance with the NAAQS for PM10 and PM2.5.
What does this mean for my health?
The amount of air pollution that is measured is compared to a health-based National Ambient Air Quality Standard (NAAQS) and converted into an Air Quality Index (AQI) value. This AQI value can range from 0-300 and communicates the amount of air pollution that is measured and how that affects our health. When the AQI value is less than 100, the air quality is considered acceptable by the EPA and is not expected to have widespread health impacts. The AQI value for Particulate Matter is less than 100 and is considered acceptable. Read more about the Air Quality Index and how it relates air pollution to your health.
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
• NCDENR - PM2.5 Non-Attainment Areas
• EPA - Particulate Matter
• EPA - Particulate Matter Emissions Toolbox
• Stationary Sources
• Mobile Sources
• Area Sources
• Health Effects of Air Pollution
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 2/20/14