Air Pollution Index Calculator
Our environmental chemistry calculator computes air pollution index accurately. Enter measurements for results with formulas and error analysis.
Reviewed by Manoj Kumar, Mathematics Educator
Formula
AQI = max(I_PM2.5, I_PM10, I_NO2, I_SO2, I_CO)
The AQI is determined by calculating sub-indices for each pollutant using piecewise linear interpolation between EPA concentration breakpoints, then taking the maximum sub-index as the overall AQI value.
Worked Examples
Example 1: Moderate Air Quality Day
Problem:PM2.5 = 20 ug/m3, PM10 = 80 ug/m3, NO2 = 40 ppb, SO2 = 20 ppb, CO = 3 ppm
Solution:Sub-index PM2.5: I = 51 + ((20 - 12.1)/(35.4 - 12.1)) * (100 - 51) = 67.7\nSub-index PM10: I = 51 + ((80 - 55)/(154 - 55)) * (100 - 51) = 63.4\nSub-index NO2: 37.7, Sub-index SO2: 28.6, Sub-index CO: 34.1\nAQI = max(67.7, 63.4, 37.7, 28.6, 34.1) = 67.7
Result:AQI = 68 (Moderate)
Example 2: Unhealthy Air Quality
Problem:PM2.5 = 80 ug/m3, PM10 = 200 ug/m3, NO2 = 120 ppb, SO2 = 100 ppb, CO = 10 ppm
Solution:Sub-index PM2.5: 163.7, Sub-index PM10: 124.7\nSub-index NO2: 102.0, Sub-index SO2: 112.3\nSub-index CO: 108.6\nAQI = max(163.7, 124.7, 102.0, 112.3, 108.6) = 163.7
Result:AQI = 164 (Unhealthy)
Frequently Asked Questions
What is the Air Quality Index (AQI)?
The Air Quality Index is a standardized numerical scale used by government agencies worldwide to communicate the level of air pollution to the public. The AQI ranges from 0 to 500, where values below 50 indicate good air quality and values above 300 represent hazardous conditions. It is calculated by measuring concentrations of major pollutants including PM2.5, PM10, nitrogen dioxide, sulfur dioxide, and carbon monoxide, then converting each to a sub-index using EPA breakpoint tables.
References
Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy