Airvoice IAQI: Understanding Indoor Air Quality Through One Number
Newsletter #13 | March 9, 2026
How do you know if the air you're breathing right now is healthy? One person feels fine in high humidity. Another calls the same air "stuffy." Some colleagues work all day with windows closed. Others feel uncomfortable within minutes and rush to ventilate.
That's exactly why Indoor Air Quality Indices exist: to translate complex measurements into a simple, actionable number that works for everyone.
The first formalized air quality index appeared in 1966 in response to New York's smog episodes. By 1976, the U.S. Environmental Protection Agency (EPA) established the Pollutant Standards Index — the foundation of today's EPA AQI. These early indices focused exclusively on outdoor air.
Indoor air quality indices came later. Researchers and companies adapted the EPA's methodology for indoor environments, replacing outdoor pollutants with indoor-relevant parameters: PM2.5, CO₂, TVOC, temperature, and humidity.
The Airvoice.Indoor platform lets you choose from multiple established standards: LEED, WELL, RESET, ISHRAE, GO IAQS, and our own Airvoice Indoor Air Quality Index (IAQI). This newsletter explains the Airvoice IAQI: what it measures, how it works, and why it matters for your indoor environment.
What the Airvoice IAQI Measures
The Airvoice IAQI runs on a 10-point scale from 1 (Good) to 10 (Hazardous). Color coding makes it instantly readable. You see at a glance whether air quality is Good, Fair, or Poor.
The index tracks three core parameters:
PM2.5 and PM10 — fine and coarse particulate matter
CO₂ — carbon dioxide
You install sensors. The system calculates. You get one number that tells you whether the air is healthy or needs attention. For deeper analysis, the platform provides detailed parameter-by-parameter data.
The platform also monitors temperature and relative humidity, displayed separately as comfort parameters. Additionally, TVOC (total volatile organic compounds) appears in your dashboard, though it doesn't factor into the IAQI calculation.
Why These Parameters
Each parameter connects directly to health or performance.
Particulate matter increases respiratory and cardiovascular risk over time. The thresholds come from EPA National Ambient Air Quality Standards and WHO guidelines. PM2.5 readings below 9 µg/m³ are Good, 9-35 µg/m³ are Fair, above 35 µg/m³ are Poor. For PM10, readings below 50 µg/m³ are Good, 50–150 µg/m³ are Fair, and above 150 µg/m³ are Poor.
Carbon dioxide affects how you think. Studies show that CO₂ above 600 ppm begins reducing cognitive function. At 900 ppm, decision-making and information processing measurably decline. High CO₂ also signals poor ventilation, meaning airborne pathogens can accumulate and spread more easily.
How IAQI Calculates Your Air Quality
The system scores each parameter separately based on measured concentrations. Your final IAQI is the highest of these three scores.
Why the highest? Because the most critical pollutant determines your air quality risk at that moment. If PM2.5 spikes to Poor while CO₂ remains Good, the index reflects the PM2.5 level. This conservative approach highlights problems when they emerge.
The Science Behind the Numbers
Airvoice IAQI builds on the internationally recognized EPA Air Quality Index. PM thresholds follow EPA NAAQS and WHO global air quality guidelines. CO₂ breakpoints come from controlled studies demonstrating measurable cognitive decline at specific concentrations.
These thresholds are scientifically validated and balance technical precision with practical usability. The underlying research spans decades. Airvoice has adapted these standards to indoor environments, where air quality can be directly managed through ventilation and filtration.
The Airvoice IAQI is a reliable tool for understanding indoor air. You don't need to interpret PM2.5 concentrations or CO₂ levels yourself. The index does that work. You see the result and know whether action is needed.
Learn more about the methodology behind the Airvoice Indoor Air Quality Index at airvoice.global
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Always here to help you breathe cleaner air,
The Airvoice Team
We design software and hardware solutions for monitoring and managing air quality in buildings, industries, and cities, and partner with leading universities worldwide on cutting-edge research.