Why Humidity Can Make PM2.5 Sensors Report Misleading Readings
A sudden PM2.5 increase during fog, mist or a humid evening does not always mean the same mass of dry particles entered your room. Optical sensor behavior matters.
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Why Your CO₂ Sensor May Be Reading Too Low: Automatic Baseline Calibration Explained
A CO₂ sensor can be precise yet wrong if its automatic baseline correction assumes the room regularly reaches outdoor-air levels. Here is how to investigate without blindly recalibrating it.
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What Is Air Velocity? Understanding Airspeed, Airflow, and Ventilation
Air velocity describes how fast air moves at a point. Airflow describes how much air passes through an area over time. Both matter in HVAC commissioning, duct measurements, ventilation diagnostics and room air distribution.
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What Is Differential Pressure? Understanding Pressure Differences in HVAC Systems
Differential pressure is the difference in static pressure between two locations. In HVAC engineering, it helps explain how air moves through filters, ducts, rooms, and equipment—not simply whether a fan is running.
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How Do NDIR CO₂ Sensors Work? Principles, Accuracy, and Limitations
Learn how NDIR CO₂ sensors measure carbon dioxide, the difference between single- and dual-channel designs, and what affects accuracy and calibration.
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Understanding ISO 16890: The Modern Standard for Air Filtration
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)…
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Airflow Dead Zones: How Poor Ventilation Alignment Creates Stagnant Air
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…
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PM1 Filtration & Air Alignment: Controlling Sub-Micron Contaminants Indoors
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…
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What Is Carbon Monoxide?
Carbon monoxide is often called the “silent killer” — it’s a colorless, odorless, tasteless gas produced whenever fuel is burned incompletely. Unlike CO₂, which is a natural byproduct of occupancy, carbon monoxide indicates that something in your home is not burning or venting properly. At high concentrations, CO can be fatal within minutes, making detectors…
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What Does “PM10” Mean?
PM10 is the “bigger sibling” of PM2.5. These particles are still far too small to see individually, but they are large enough to behave differently in the air and in the body — and they come from a somewhat different set of sources. In this guide What Does “PM10” Mean? PM10 vs. PM2.5: What’s the…
