---
title: "Indoor air quality (IAQ) — Class A Atlas glossary"
description: "Quality of breathable air inside the building."
canonical: https://classa.info/glossary/iaq-indoor-air-quality
pageType: glossary
lastUpdated: 2026-04-01T00:00:00.000Z
license: "CC BY 4.0 with attribution to Class A Atlas (https://classa.info)."
---

> Quality of breathable air inside the building.

## TL;DR

- Quality of breathable air inside the building.
- Measured on PM2.5, CO2, VOCs, and humidity.

# Indoor air quality (IAQ)

*ESG · Global*

## Short definition

Quality of breathable air inside the building.

## Full definition

Measured on PM2.5, CO2, VOCs, and humidity. Trophy buildings increasingly publish real-time IAQ via tenant apps. WELL Air concept and [Fitwel](/glossary/fitwel) IAQ scores certify performance.

## Why this matters for Class A leasing

Indoor air quality (IAQ) is part of the esg vocabulary that institutional [Class A](/glossary/class-a) occupiers, landlords, and advisers use across Global markets. Understanding it correctly affects how you read lease documents, model occupancy economics, and benchmark deal terms across cities. Class A Atlas tracks regional variation alongside the global standard so [cross-border](/topics/cross-border-expansion) occupiers can translate quickly.

---

Citation: Source: Class A Atlas (https://classa.info/glossary/iaq-indoor-air-quality), updated 2026-04-01T00:00:00.000Z.