INDOOR AIR MONITOR NOTESSource-based notes · UK English
AirMeasure UKA TITLE IS NOT A SENSOR

THE SENSORS NOTES

Sensor notes

A product title is a list of words. A sensor is a named measurement principle.

AirMeasure UKUpdated

What is the difference between a product title and a named sensor?

A product title can list PM2.5, carbon dioxide, TVOC and HCHO without naming a measurement principle. A named sensor states the method: laser scattering for particles, NDIR or photoacoustic detection for carbon dioxide, an electrochemical cell, or a metal-oxide film. These notes use that distinction. They do not treat the four related shop listings as confirmed instruments, and this publication has not published original room series. Adafruit’s SCD-30 page names NDIR; a shop title that only prints CO₂ does not.

NoteThe distinction it keeps
Title versus bodyCatalogue words stay unused until the body names a principle.
True CO₂ versus eCO₂NDIR or photoacoustic detection is not an SGP30-style estimate.
Particles versus gasesA laser spike is not a formaldehyde result.
TVOC and HCHOA relative index or an electrochemical cell is not a traceable concentration.

How do true carbon dioxide, particles and low-cost gas readings differ?

True carbon dioxide on these pages means NDIR or photoacoustic detection, as the Adafruit SCD-30 and SCD-4x tutorials describe, not an eCO₂ estimate from a metal-oxide sensor such as the SGP30. A laser channel counts scattered particles. An electrochemical listing and a metal-oxide TVOC index are different measurements again. AirGradient’s photoacoustic comparison is a manufacturer post and is labelled as such. None of those figures is an AirMeasure UK co-location, and a consumer reading is not a medical result.

Still-life of a dark-screen air monitor, a blank grid sheet, a wooden window and a saucepan lid.
Explanatory still-life of the file ingredients. Not an AirMeasure UK test.
Four blank hang-tags above a single unmarked sensor block.Source-based note

A product title is not a sensor

Four related retail listings name PM2.5, CO₂ or HCHO in the title. Only the body text, and only where it names a principle, can be treated as a clue.

8 MIN READ An unmarked glass sensing tube beside a plain white cylinder and a small circuit board.Source-based note

True carbon dioxide is not eCO₂

NDIR and photoacoustic sensors measure carbon dioxide. SGP30-style eCO₂ estimates it from volatile organics. The two numbers do not answer the same question.

8 MIN READ Fine dust in a shaft of light beside a black optical cube and a small metal cell.Source-based note

Particles and gases are different sensors

A laser counts scattered particles. Infrared, electrochemical and metal-oxide sensors look at gases. A cooking spike is a particle event until a gas sensor of a named type is also in the log.

7 MIN READ A blank dial with no numerals, a small metal sensor and an empty checkbox card.Source-based note

Low-cost TVOC and HCHO stay relative

Metal-oxide TVOC is a relative index with cross-sensitivity and a learning baseline. An electrochemical formaldehyde cell is not a traceable HCHO method.

8 MIN READ