Learning Center

Plain-language explanations of the measurements, sensors and numbers behind environmental monitoring.

Decibels filtered to match human hearing. It is the unit almost every noise limit uses.

A microphone, a weighting filter and a decibel display, built to a standard so readings can be compared.

Vanes for grilles and wind; hot-wires for low speeds and small holes. Each has a blind spot.

Air speed, and from it airflow: the number behind vents, fans, fume hoods and weather.

Same physics, different corrections, references and housings. The gap is usually explainable.

Calibration finds out how wrong an instrument is. Adjustment changes it. They are separate steps.

The smallest step the display can show. Counts, digits and why 6000 is better than 2000 but not more accurate.

Measure the same thing twice and get the same answer. Repeatability is how close the two are.

The honest range around a reading. Every measurement has one, whether or not the display admits it.

A sensor has mass. It has to reach the temperature of the air before it can report it.

A sensor measures the air touching it. Where that air came from decides what the number means.

Fast enough to catch the event you care about, slow enough to last. Usually 1 to 15 minutes.