Air Quality Index Calculator
Compute air quality index using validated scientific equations. See step-by-step derivations, unit analysis, and reference values.
Formula
AQI = max(sub-indices)
Linear interpolation in EPA breakpoints, take maximum.
Worked Examples
Example 1: Moderate
Problem: PM2.5=22,PM10=70,O3=45,NO2=35,SO2=15
Solution: PM2.5=72,PM10=58,O3=42,NO2=33,SO2=21 AQI=72
Result: AQI=72
Example 2: Unhealthy
Problem: PM2.5=90,PM10=200,O3=95,NO2=150,SO2=90
Solution: PM2.5=170,O3=176 AQI=176
Result: AQI=176
Frequently Asked Questions
What is air quality index?
air quality index is a measurement used in environmental science to quantify the impact of specific pollutants or emissions on ecosystems and human health. Air Quality Index Calculator uses established scientific formulas from peer-reviewed research and government agency guidelines to produce accurate estimates. The results are expressed in standardized units that allow comparison across different sources and scenarios. Understanding these values helps organizations and individuals make informed decisions about emission reduction strategies.
How is air quality index calculated?
The calculation uses the formula AQI=max(sub-indices) which is derived from well-established environmental science principles. Each input variable represents a measurable quantity that contributes to the final result. The calculator applies appropriate conversion factors and emission coefficients from IPCC guidelines and EPA databases. Intermediate steps are shown so you can verify each part of the calculation independently.
How is water quality measured?
Key water quality metrics include pH (6.5-8.5 for drinking water), dissolved oxygen (above 5 mg/L for aquatic life), turbidity (below 1 NTU for drinking water), total dissolved solids, biological oxygen demand (BOD), and coliform bacteria count. Each parameter has regulatory limits set by the EPA.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Can I use Air Quality Index Calculator on a mobile device?
Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.
How do I get the most accurate result?
Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.