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.
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.
EPA’s Enhanced Air Sensor Guidebook is a step-by-step reference for readers designing an air quality sensor project and making sense of the results.
Good sensor data requires a plan for how instruments will be installed, checked, maintained and interpreted—not simply turning devices on.
Correct sensor placement is essential for collecting useful air quality data. EPA’s siting guide explains practical issues that can make a reading unrepresentative.
EPA’s performance targets and testing protocols are designed to help users understand how air sensor measurements compare with reference instruments for defined applications.
ASHRAE Standard 55 is a widely used reference for thermal environmental conditions intended to support acceptable comfort for occupants.
EPA’s CompTox Chemicals Dashboard is a broad technical resource for looking up chemical identities, properties and associated toxicology or exposure information.
OpenAQ helps make publicly available air quality measurements easier to discover and use for analysis, research and public communication.
AirNow explains the U.S. Air Quality Index (AQI), a color-coded way to communicate outdoor air pollution and potential health concern.