EPA’s Indoor Air Quality resources help homeowners, facility managers and educators understand pollution sources and practical approaches to healthier indoor environments.
ASHRAE Standards 62.1 and 62.2 are major technical references for ventilation and acceptable indoor air quality in buildings.
WHO’s Global Air Quality Guidelines provide health-based reference levels for major air pollutants and help readers put numerical measurements into context.
The EPA Air Sensor Toolbox is a useful starting point for anyone trying to understand what air sensors can measure, how they perform, and how to interpret the data they produce.
Learn how NDIR COâ‚‚ sensors measure carbon dioxide, the difference between single- and dual-channel designs, and what affects accuracy and calibration.
Basics • 7 min read For decades, air filtration in general ventilation systems relied on classifications like EN779 or ASHRAE 52.2. However, these older frameworks evaluated filter media using single, artificial particle sizes that rarely reflected real-world atmospheric conditions. The transition to ISO 16890 established a global testing regime aligned directly with particulate matter (PM)…
An HVAC system can operate at full capacity, running high-grade filters and delivering conditioned air, yet occupants in certain parts of a room may still experience stuffiness, elevated temperature gradients, or lingering odors. This phenomenon is caused by airflow dead zones—pockets of space where air circulation stalls despite an active ventilation infrastructure. In this guide…
When discussing indoor air pollution, public attention typically focuses on visible dust or larger particulates like PM10 and PM2.5. However, from an air handling, filtration engineering, and HVAC alignment perspective, the most challenging atmospheric contaminant is PM1. In this guide Comparing Particulate Sizes & Physical Dynamics Why Ultra-Fine Particles Behave Differently Indoors The Role of…
Mold is one of the most common and stubborn indoor air quality problems in homes — and in almost every case, the root cause is excess moisture. Mold spores are always present in indoor air, but they only grow when relative humidity stays above 60% or when water damage leaves surfaces damp for more than…