AQHI to AQI Converter
Adjust the slider to convert
Low Risk Moderate Risk High Risk Very High Risk
Good Moderate Unhealthy for Sensitive Groups Unhealthy Very Unhealthy Hazardous
Based on PM₂.₅ concentration of
The AQHI formula combines health risks from PM₂.₅, ozone (O₃), and nitrogen dioxide (NO₂). Even if PM₂.₅ stays the same, higher O₃ or NO₂ levels raise the AQHI's “baseline” risk. By default O₃ and NO₂ are set to 0, so the AQHI is attributed entirely to PM₂.₅. Adjust the sliders below to see how background pollutants affect the result.
This converter is for educational purposes only. Actual AQHI and AQI values depend on real-time measurements of multiple pollutants. The conversion assumes background O₃ and NO₂ levels and should not be used for health decisions.
Convert AQHI (Canada) to AQI (US EPA) free online using PM2.5 as the common reference. Bidirectional conversion with PM2.5 values shown. Runs in your browser.
How to Convert AQHI to AQI
Input AQHI Value
Enter the AQHI value you want to convert. The AQHI ranges from 1 to 10+.
Click Convert
Click the convert button to transform the Canadian AQHI to the US AQI equivalent.
View Results
Review the converted AQI value and corresponding health risk category.
How It Works
AQHI (Air Quality Health Index)
Canada's AQHI is a health-based index measuring the combined risk of PM2.5, ozone, and nitrogen dioxide on a scale from 1 to 10+. It uses a formula based on the excess mortality risk of each pollutant to indicate health risk.
AQI (Air Quality Index)
The US EPA AQI ranges from 0 to 500 across six color-coded categories. Linear interpolation within breakpoint ranges converts pollutant concentrations to an index value. Higher values mean greater health concern.
PM₂.₅ as the Bridge
PM2.5 (fine particulate matter) serves as the common reference between AQHI and AQI. By default O₃ and NO₂ are set to 0, attributing the AQHI entirely to PM2.5. This provides an approximate equivalent — actual indices use real-time multi-pollutant measurements.
Risk Level Guide
FAQ
Why doesn't this match official readings?
Official AQHI and AQI use real-time multi-pollutant data. This converter uses PM2.5 only and assumes background levels for O₃ and NO₂. For accurate readings, check your local air quality monitoring agency.
What are the limitations?
The converter uses the 24-hour PM2.5 AQI breakpoints, and the background O₃/NO₂ fields default to 0 — so out of the box the AQHI side reflects PM2.5 alone. Real AQHI readings use real-time measurements of several pollutants, so local conditions can differ noticeably.
How does adjusting O₃ and NO₂ affect the results?
The AQHI formula includes health risks from PM₂.₅, O₃, and NO₂ together. When you increase O₃ or NO₂, the AQHI's "baseline risk" goes up — even if PM₂.₅ hasn't changed, the AQHI will be higher. Try this: keep the PM₂.₅ value fixed and drag the O₃ slider to watch the AQHI change in real time.
If I set O₃ and NO₂ to 0, is that more accurate?
Setting O₃ and NO₂ to 0 makes the AQHI reflect only PM₂.₅'s contribution, but that does not mean real air contains none of them. Urban air always carries trace amounts — try 30 ppb O₃ and 20 ppb NO₂ as a typical city background and watch how much the AQHI rises. The 0 setting is for what-if analysis: it isolates how much PM₂.₅ alone contributes.
What's the difference between AQHI and AQI?
AQHI (Canada's Air Quality Health Index) is a 1–10+ health risk index that tells you how air quality affects your health. AQI (the US Air Quality Index) is a 0–500 scale that focuses more on pollution level. They use different formulas: AQHI is exponential (more pollutants = each additional unit has a bigger health impact), while AQI is piecewise linear. This is why the same PM₂.₅ concentration may produce different trends in the two indices.
Can I use this tool for health decisions?
No. This tool is for learning how AQHI and AQI relate to each other and how O₃/NO₂ affect the conversion. Real air quality assessment requires real-time monitoring data. Please check official sources like AirNow (US) or Environment Canada AQHI for accurate information.
Guides
Longer write-ups on the things these tools deal with: file formats, size limits, and the algorithms behind them.