🧪 Formaldehyde in workplace air according to PN-Z-04045-02 — and the twin part of the standard on the same formaldehyde

Environment PN-76/Z-04045/02

Overview

STATUS (state of the PKN card on 23.09.2026). PN-Z-04045-02:1976 — Polish version — is WITHDRAWN. Publication date 04-06-1976, WITHDRAWAL DATE 17-10-2011, number of pages 3, technical body KT 159 (Chemical and Dust Hazards in the Working Environment), ICS 13.040.30. The card states what this standard replaced ("PN-Z-04034:1966 — Polish version"), but HAS NO "Replaced by" row — it was withdrawn without a successor being indicated.

TWO PARTS OF THE SAME SERIES DETERMINE THE SAME FORMALDEHYDE. Part 02 (this one) speaks of a colorimetric method WITH PHENYLHYDRAZINE. Part 04 — PN-Z-04045-04:1976, published on the same day, 04-06-1976, withdrawn earlier, on 23-08-2006, two pages — is entitled "Determination of formaldehyde at workplaces by the colorimetric method WITH CHROMOTROPIC ACID". The same substance, the same workplace, a different colour reagent. Both stand in the accreditation scopes: part 02 in 23 entries, part 04 in 5 entries.

AND FROM THIS FOLLOWS SOMETHING THAT CHANGES THE ARRANGEMENT OF THIS ENTRY. If one searched for laboratories for this entry by the shortened number "PN-76/Z-04045", one would find 24 entries at 22 laboratories — but this number includes five entries citing PART 04, i.e. the method with chromotropic acid. That is why this entry searches by the fuller notation "PN-76/Z-04045/02": it gives 15 entries at 14 laboratories and does not mix the two methods. The price is that it misses eight entries in which part 02 was written with a different separator — "PN-76/Z-04045.02" (2), "PN-76/Z-04045-02" (2), "PN-76-Z-04045.02" (1) and "PN-Z-04045-02:1976" in the new scheme (2). THE FULL SCALE OF CITATIONS OF PART 02 IS 23 ENTRIES AT 21 LABORATORIES; the "Laboratories" tab will show 15 of them at 14.

THE TITLE SAYS "COLORIMETRIC", THE SCOPES SAY "SPECTROPHOTOMETRIC" — just as with chlorine. Eighteen entries declare a spectrophotometric technique. We do not settle whether this is the same activity called by a newer word: we did not have the text of the standard.

MEASURING RANGES. Declared in the scopes: (0.025 – 5.5) mg/m³, (0.035 – 2) mg/m³, (0.037 – 5.30) mg/m³, (0.048 – 5.33) mg/m³, (0.05 – 5.0) mg/m³, (0.13 – 6.6) mg/m³, and as mass in the sample (0.00015 – 0.012) mg and (0.0003 – 0.8) mg. The lower limits differ fivefold.

AGAINST WHAT THESE NUMBERS APPLY. Formaldehyde has in the list of limit values an NDS of 0.37 mg/m³ (0.3 ppm) and an NDSCh of 0.74 mg/m³ (0.6 ppm) — item 260 of Annex No. 1 in the wording given by the regulation of 26 March 2026 (Journal of Laws 2026 item 447, in force since 2 April 2026). The same item carries the "skin" notation and the footnote: "Substancja może mieć działanie uczulające na skórę" [the substance may have a skin-sensitising effect]. THE LIMIT VALUE IS LOW HERE IN RELATION TO THE RANGES: a laboratory with a lower limit of 0.13 mg/m³ measures only one third of the NDS, and a laboratory with a limit of 0.025 mg/m³ — roughly one fifteenth. In exposure assessment this is a decisive difference, and in the "range" column it looks like a trifle.

WHY A WITHDRAWN STANDARD STILL STANDS IN THE SCOPES. § 16 of the regulation of the Minister of Health on tests and measurements of agents harmful to health in the working environment (consolidated text — Journal of Laws 2025 item 949): "Badania i pomiary wykonuje się zgodnie z metodami określonymi w Polskich Normach, a w przypadku braku takich norm, metodami rekomendowanymi i zwalidowanymi przez laboratoria, o których mowa w § 15 ust. 1 i ust. 2 pkt 1" [Tests and measurements are carried out in accordance with the methods specified in Polish Standards, and in the absence of such standards, with methods recommended and validated by the laboratories referred to in § 15(1) and (2)(1)]. Whether the withdrawal of a standard by PKN is an "absence of a Polish Standard" within the meaning of this provision — WE DO NOT SETTLE. In two entries in the scopes, the number of the laboratory's own procedure stands next to the standard ("PB-09 Edycja 7 z dnia 14.07.2023 r." and "EV-IR/54 wydanie 1 z dnia 31.01.2020" [procedure numbers with edition and date]).

WHAT WE DO NOT GIVE. We did not have the text of the standard. We DO NOT GIVE the way of sampling, the volume of air, the composition of the absorption solution with phenylhydrazine, the measurement wavelength or the calculation of the result.

TWO NAMES FOR THE SAME SUBSTANCE (23.09.2026). In accreditation scopes formaldehyde is sometimes also called "aldehyd mrówkowy" [formic aldehyde]. Measurement on the copy of the scopes, test name or parameter, with inflection by case: "formaldehyd" 92 laboratories / 243 entries, "aldehyd mrówkowy" 8 / 11 — in 6 of these 11 entries the test object is water or waste water. When searching for laboratories, it is worth entering both names.

Method principle

Formaldehyde from the air is retained in an absorption solution and forms with phenylhydrazine a coloured product whose colour intensity is a measure of the content — this is what the title of the standard says, calling the method colorimetric. In their scopes, laboratories declare a spectrophotometric measurement. The concentration in air is calculated by dividing the mass of formaldehyde in the sample by the volume of air sampled, so the lower limit of the range depends on the volume sampled. WE DO NOT DESCRIBE THE DETAILS OF EXECUTION: we did not have the text of the standard.

Applications

• Measurement of the concentration of formaldehyde in workplace air
• Assessment of occupational exposure against the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³
• Reading an accreditation scope in which a standard withdrawn in 2011 stands next to formaldehyde
• Distinguishing two parts of the same series: the method with phenylhydrazine (part 02) and with chromotropic acid (part 04)

Key parameters

Standard

Standard number

PN-Z-04045-02:1976 (wersja polska)

Title (PL)

Ochrona czystości powietrza — Badania zawartości aldehydów — Oznaczanie formaldehydu na stanowiskach pracy metodą kolorymetryczną z fenylohydrazyną

Step-by-step procedure

1. Checking WHICH part of the series stands in the scope

   Distinguish part 02 (phenylhydrazine, withdrawn 17-10-2011) from part 04 (chromotropic acid, withdrawn 23-08-2006). Both concern formaldehyde at workplaces and both appear in accreditation scopes.

2. Establishing the basis for carrying out the measurement

   If the description of the method comes from the laboratory's own procedure, its number and edition should stand in the reference documents next to the standard. § 16 of the regulation on tests and measurements permits validated methods in the absence of a Polish Standard.

3. Taking the air sample

   Draw the air through the absorption solution under the conditions established in the procedure and record the volume of air — without it the mass of formaldehyde cannot be converted into a concentration.

4. Developing and measuring the colouration

   After the reaction with the colour reagent, measure the colour intensity against a calibration curve. The scopes declare a spectrophotometric technique; the title of the standard speaks of colorimetry with phenylhydrazine.

5. Converting to the concentration in air

   Divide the mass of formaldehyde in the sample by the volume of air sampled. This is where the difference in lower limits between laboratories arises — with the same determinable mass, a larger volume of air gives a lower limit.

6. Relating to the limit values

   Compare with the NDS of 0.37 mg/m³ and the NDSCh of 0.74 mg/m³ (item 260 of Annex No. 1, wording of Journal of Laws 2026 item 447). At the same time check whether the lower limit of the range makes it possible at all to establish the fraction of the limit value required in exposure assessment.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Formaldehyde has the "skin" notation in the list and a footnote on a possible skin-sensitising effect — when sampling, skin protection applies, not only respiratory protection
• Two parts of the same series concern the same formaldehyde and differ in the reagent — a citation of "PN-76/Z-04045" without the part number does not say which method the laboratory performs
• Searching for laboratories by the shortened series number mixes both methods: the result will include laboratories performing the determination with chromotropic acid
• The standard has been withdrawn since 17-10-2011 and has no successor on the card — citing it without indicating the laboratory's own procedure does not say where today's description of the method comes from
• A measuring range with a lower limit of 0.13 mg/m³ against an NDS of 0.37 mg/m³ does not make it possible to establish low fractions of the limit value — a result "below the limit of quantification" then means less than it appears

Frequently asked questions