Air Quality Index Calculator
PM2.5 (Fine Particles)
Calculate AQI from PM2.5 concentration
PM10 (Coarse Particles)
Calculate AQI from PM10 concentration
Ozone (O3)
Calculate AQI from ozone concentration
Formula
AQI = ((IHi - ILo) / (BPHi - BPLo)) × (Cp - BPLo) + ILo | where Cp = concentration, BP = breakpoint, I = AQI index value
Frequently Asked Questions
What is AQI and how is it calculated?
The Air Quality Index (AQI) is a standardized scale from 0-500 that translates pollutant concentrations into health risk categories. The EPA uses a piecewise linear function to convert raw concentrations of pollutants (PM2.5, PM10, ozone, CO, SO2, NO2) into a unified 0-500 index.
What AQI level is safe?
AQI 0-50 (Good/Green) is considered safe for everyone. AQI 51-100 (Moderate/Yellow) is acceptable but may affect unusually sensitive people. Above 100, sensitive groups should reduce outdoor activity. Above 150, everyone should limit exposure.
What causes bad air quality?
Major causes include: vehicle emissions, industrial pollution, wildfires, dust storms, power plant emissions, and chemical reactions forming ground-level ozone. PM2.5 from wildfires is a growing concern in many US regions.
You may also need
A
Humidity Calculator
Free relative humidity calculator. Calculate relative humidity from temperature and dew point, plus comfort level assessment.
ScienceA
Wind Chill Calculator
Free wind chill calculator. Calculate the wind chill temperature index from air temperature and wind speed.
ScienceH
UV Index Calculator
Free UV index calculator. Understand UV risk levels, recommended SPF, and safe sun exposure times for different skin types.
Health