As you are driving down the busy highway, and see an air quality alert displayed on the electronic signboards, have your every stopped to think about what the alert really means and how it affects you? The EPA calculates the Air Quality Index (AQI) for 5 major pollutants:

Ground-Level Ozone – According to the EPA this “bad” ozone “is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight.   Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOC”. Breathing ozone can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma. Ground level ozone can also have harmful effects on sensitive vegetation and ecosystems.

Particle (Matter) Pollution (PM) – is a mixture of solid particle and liquid droplets found in the air. Examples are dust, smoke, fumes, or smog found in air or emissions. Particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream.

Carbon Monoxide (CO) –  is a colorless, odorless, and tasteless gas which is a results from a combustion of fuels. CO is released from automobiles, machinery, kerosene and gas heaters, leaking chimneys and furnaces, and gas stoves. At low concentrations it can cause fatigue in healthy people and chest pain in those with heart disease. In moderate concentrations it can cause angina, impaired vision, and reduced brain function. At higher concentrations it can cause impaired vision and coordination, headaches, dizziness, confusion, nausea, flu-like symptoms, and can be fatal at very high concentrations.

Sulfur Doxide (SO2) – is a colorless pungent toxic gas formed by burning sulfur in the air. SO2 is primarily emitted from the burning of fossil fuels by power plants and industrial facilities. Short-term exposures to SO₂ can harm the human respiratory system and make breathing difficult. Children, the elderly, and those who suffer from asthma are particularly sensitive to effects of SO₂.

Nitrogen Dioxide (NO2) –  is a reddish brown poisonous gas used in the manufacture of nitric acid. It is also an air pollutant, a constituent of untreated automobile exhaust. NO2 can irritate the airways in the human respiratory system. The EPA states “ Longer exposures to elevated concentrations of NO₂ may contribute to the development of asthma and potentially increase susceptibility to respiratory infections”.

Now that you know about  the 5 major pollutants that are monitored by the EPA,  how does  the Air Quality Index work? To help make it easy for the laymen to understand if air pollution is reaching unhealthy levels nearby, the EPA has divided  the AQI  into six categories and has assigned a specific color to each.

EPA Air Quality Index :

GREEN= “Good” AQI is 0 to 50. Air quality is considered satisfactory, and air pollution poses little or no risk.

YELLOW= “Moderate” AQI is 51 to 100. Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people. For example, people who are unusually sensitive to ozone may experience respiratory symptoms.

ORANGE= “Unhealthy for Sensitive Groups” AQI is 101 to 150. Although general public is not likely to be affected at this AQI range, people with lung disease, older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air.

RED= “Unhealthy” AQI is 151 to 200. Everyone may begin to experience some adverse health effects, and members of the sensitive groups may experience more serious effects.

PURPLE= “Very Unhealthy” AQI is 201 to 300. This would trigger a health alert signifying that everyone may experience more serious health effects.

MAROON= “Hazardous” AQI greater than 300. This would trigger a health warnings of emergency conditions. The entire population is more likely to be affected.

Not sure where to check your local air quality? You can check on the internet, subscribe to receive air quality notifications via email , and through local and national television, radio, and newspapers.