EngineeringToolkit

Air Quality Index Formula

Calculates Air Quality Index from pollutant concentration.

Formula

AQI = ((IHi - ILo)/(CHi - CLo)) × (C - CLo) + ILo

Discipline: Environmental Engineering. Result unit: dimensionless.

Variables and units

  • AQI — AQI: Air Quality Index
  • IHi — Index High: Upper AQI breakpoint
  • ILo — Index Low: Lower AQI breakpoint
  • CHi — Concentration High (μg/m³): Upper concentration breakpoint
  • CLo — Concentration Low (μg/m³): Lower concentration breakpoint
  • C — Concentration (μg/m³): Pollutant concentration