Section 01 · The Field E-01

The limit decides what ‘clean’ means

A result below the detection limit is not zero — it is “not seen by this method for this long”. Change the sampler or the duration and the same air produces a different sentence.

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A gloved finger presses a button on a dental micromotor control unit's display panel — FIG. 01“Not detected” is a sentence about the method, not about the air.Photo: kaboompics.com / Pexels

EACH ENTRY STATES THE METHOD, THE DURATION AND THE LIMIT IT REPORTS TO.
A RESULT WITHOUT THOSE THREE IS NOT A RESULT.

THE METHOD REGISTERfive ways air is collected, and what each one can honestly report

No.	Method	Typical run	Reports as
M-01	Diffusive badge	7–28 days	µg/m³, time-averaged
M-02	Pumped sorbent tube	10 min – 8 h	µg/m³
M-03	DNPH cartridge	1–24 h	µg/m³
M-04	Evacuated canister	seconds to 24 h	µg/m³
M-05	Emission chamber	3–28 days	µg/(m²·h)

A concentration describes air at a place and time; an emission rate describes a surface. The register keeps them apart on purpose.

FROM THE REGISTERan edit, not the index — the full roster lives on the section pages

Section 02 · The Chamber E-07

Gloved hands work at a lab bench surrounded by monitors, cables and a sealed testing chamber

Emission in a sealed box

A specimen in a chamber with controlled temperature, humidity and air exchange, sampled at intervals to give a rate rather than a level.

E-12

From tube to number

Thermal desorption, separation, detection, integration. Four steps, each with its own way of being wrong.

THE BENCH

E-17

The paper chain

Registration, evaluation and authorisation: the sequence a substance moves through before anything may be said about it in commerce.

THE DOSSIER

E-02

The diffusive badge

No pump, no power: molecules arrive by diffusion at a rate the geometry fixes. Left for two weeks, it reports an average.

THE FIELD

E-15

Integration

Where the operator decides a peak starts and stops.

THE BENCH

The full register — all 21 entries →

Capped glass sorbent tubes in a rack — FIG. 02Capped, numbered, racked: a sorbent tube becomes a record the moment it is sealed. Every method in the register ends in one.

THE SECTIONSfour links in the chain between a volume of air and a line on a report

The Field

Two weeks on a wall, or eight hours on a pump.

6 ENTRIES
ENTER →

The Chamber

Emission measured in a sealed box.

5 ENTRIES
ENTER →

The Bench

Turning a tube into a number.

5 ENTRIES
ENTER →

The Dossier

The paper chain a substance moves through.

5 ENTRIES
ENTER →

THE PAPER CHAINwhat a sample must generate before its number may be cited

The sampling plan

What, where, for how long and by which method — decided in writing before anything is opened.

Custody

The sample never travels unaccompanied. Every handover is signed and timed on one form.

Analysis

An accredited method, run with blanks and duplicates in every batch, on a calibrated instrument.

Validation

Recoveries, control charts and proficiency rounds — the laboratory proving itself against others.

The report

The number, its uncertainty and its limits printed together. Only this page may be quoted.

The regulatory version of this chain — E-17, The paper chain →

A passive diffusive sampler badge on a plain wall, hard side light — PLATE I — THE FIELDA diffusive sampler at work, which is to say: motionless. The geometry of the opening fixes the sampling rate; the fieldworker’s only instruments are a clock and a pen.

THIS PUBLICATION DESCRIBES INSTRUMENTS, METHOD AND PROCEDURE.
IT CARRIES NO HEALTH INFORMATION OF ANY KIND.