Advanced Air Quality Index Calculator

Calculation mode

AQI standard

Health group

Pollutant concentrations

Leave unused pollutants blank. The largest valid sub-index becomes the overall AQI.

PM2.5

PM10

Ozone (O₃)

Carbon Monoxide (CO)

Sulfur Dioxide (SO₂)

Nitrogen Dioxide (NO₂)

Ammonia (NH₃)

Current-condition NowCast

Use hourly PM NowCast

NowCast pollutant

Hourly readings, oldest to newest

Reverse AQI lookup

Target AQI

Pollutant

Averaging period

Measurement and conversion settings

Temperature (°C)

Pressure (kPa)

Calibration factor

Measurement date and time

Data quality

Location

Station name

Sensor name

Custom breakpoint editor

Provide a JSON object keyed by pollutant code. Each breakpoint uses: AQI low, AQI high, concentration low, concentration high.

Batch CSV processing

Use headers such as PM25, PM10, O3, CO, SO2, NO2, and NH3. Up to 500 rows are processed.

CSV file

Batch concentration unit

Formula used

Each pollutant concentration is converted into its standard unit. Required precision rules are then applied before interpolation.

I = ((IHigh − ILow) / (BPHigh − BPLow)) × (C − BPLow) + ILow

The highest pollutant sub-index becomes the overall AQI. Results are capped at 500 when inputs exceed configured ranges.

How to use this calculator

Select an AQI standard and calculation direction.
Enter one or more pollutant concentrations.
Choose the correct unit and averaging period.
Set temperature and pressure for gas conversions.
Optionally add hourly PM readings or a CSV file.
Press Calculate AQI and review the dominant pollutant.
Export results as CSV, JSON, print, or PDF.

JSON API endpoint

Send a POST request with Content-Type: application/json to this same PHP file.

{
  "standard": "US_EPA",
  "temperature_c": 25,
  "pressure_kpa": 101.325,
  "values": {"PM25": 21.4, "O3": 0.062},
  "units": {"PM25": "ug_m3", "O3": "ppm"},
  "periods": {"PM25": "24h", "O3": "8h"}
}

Important limitations

Use validated regulatory data for official reporting. Low-cost sensors can require humidity correction, calibration, and quality review.

Health guidance is general information, not medical advice. Follow local authorities during smoke, industrial releases, or emergency conditions.