Air Quality Index (AQI)
How Does the AQI Work?
Think of the AQI as a yardstick that runs from 0 to 500, the higher the AQI value, the greater the level of air pollution and the greater the health concern, for example, an AQI value of 50 represents good air quality with little potential to affect public health, while an AQI value over 300 represents hazardous air quality. An AQI value of 100 generally corresponds to the national air quality standard for the pollutant, which is the level EPA, has set to protect public health. AQI values below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is considered to be unhealthy-at first for certain sensitive groups of people, then for everyone as AQI values get higher.
Understanding the AQI
To make it easier to understand, the AQI is divided into six categories:
|Air Quality Index
|Levels of Health Concern||Colors|
|When the AQI is in this range:||..air quality conditions are:||...as symbolized by this color:|
|101-150||Unhealthy for Sensitive Groups||Orange|
|151 to 200||Unhealthy||Red|
|201 to 300||Very Unhealthy||Purple|
|301 to 500||Hazardous||Maroon|
Each category corresponds to a different level of health concern. The six levels of health concern and what they mean are:
"Good" AQI is 0 - 50. Air quality is considered satisfactory, and air pollution poses little or no risk.
"Moderate" AQI is 51 - 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.
"Unhealthy for Sensitive Groups" AQI is 101 - 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.
"Unhealthy" AQI is 151 - 200. Everyone may begin to experience some adverse health effects, and members of the sensitive groups may experience more serious effects.
"Very Unhealthy" AQI is 201 - 300. This would trigger a health alert signifying that everyone may experience more serious health effects.
"Hazardous" AQI greater than 300. This would trigger a health warnings of emergency conditions. The entire population is more likely to be affected.
EPA has assigned a specific color to each AQI category to make it easier for people to understand quickly whether air pollution is reaching unhealthy levels in their communities. For example, the color orange means that conditions are "unhealthy for sensitive groups," while red means that conditions may be "unhealthy for everyone," and so on.
|Air Quality Index Levels of Health Concern||Numerical Value||Meaning|
|Good||0 to 50||Air quality is considered satisfactory, and air pollution poses little or no risk|
|Moderate||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 who are unusually sensitive to air pollution.|
|Unhealthy for Sensitive Groups||101 to 150||Members of sensitive groups may experience health effects. The general public is not likely to be affected.|
|Unhealthy||151 to 200||Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.|
|Very Unhealthy||201 to 300||Health warnings of emergency conditions. The entire population is more likely to be affected.|
|Hazardous||301 to 500||Health alert: everyone may experience more serious health effects|
Air Quality Index (AQI)
NNEPA AQCP uses the AQI EPA web link to assist with converting the monthly average concentrations to the AQI values. The purpose of the AQI is to help you understand what local air quality means to your health. Therefore, a table is provided with the air monitoring concentration converted to the AQI values below:
|Fort Defiance PM2.5||Shiprock PM10||Crownpoint PM10||Tuba City PM10||Nazlini PM 2.5||Nazlini PM 2.5|