AQI Calculator
Air Quality Index from pollutant concentrations (PM2.5, PM10, O3, CO, SO2, NO2) using EPA breakpoint tables.
Inputs
Results
AQI Value
78
Category (1–6)2
Concentration Used25
How to Use This Calculator
- Enter Pollutant and Concentration.
- Review the AQI Value result.
- Use Category (1–6) and Concentration Used to inform your decision.
How the result changes with Concentration
| Concentration | AQI Value |
|---|---|
| 100 | 174 |
| 350 | 400 |
| 650 | 500 |
| 900 | 500 |
What each input means
- Pollutant
- 1 = PM2.5 (μg/m³), 2 = PM10 (μg/m³), 3 = O3 (ppm), 4 = CO (ppm), 5 = SO2 (ppb), 6 = NO2 (ppb).
- Concentration
- Measured pollutant concentration in the unit appropriate for the selected pollutant.
What each result means
- AQI Value
- EPA Air Quality Index (0–500). Higher values indicate worse air quality.
- Category (1–6)
- 1 = Good, 2 = Moderate, 3 = Unhealthy for Sensitive Groups, 4 = Unhealthy, 5 = Very Unhealthy, 6 = Hazardous.
- Concentration Used
- The input concentration value used for the AQI calculation.
How this is calculated
Worked example, using the default values
- Identify Input ParametersPollutant = 1, Concentration = 25 = 2 input(s) provided
- Calculate AQI ValueAQI Value = computeAqi(concentration, breakpoints)78 = 78
- Calculate CategoryCategory2 = 2
- Calculate Concentration Used25 = 25
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Air Quality
Indoor Air Quality Score Calculator
IAQ assessment from CO2, VOC, humidity, and particulates.
EcologyWater Quality Index (WQI) Calculator
Calculate a composite Water Quality Index (0-100) from dissolved oxygen, pH, BOD, nitrate, phosphate, turbidity, and temperature change.
Air QualityDust Particle Settling Calculator
Calculate particle settling velocity and time using Stokes' law with Cunningham slip correction.
Air QualityVehicle Emissions Calculator
Annual emissions from vehicle type, age, and mileage.
More in Environment, Weather & Climate.