🌿 Magnesium oxide in workplace air — flame atomic absorption spectrometry (FAAS); lowest determinable concentration according to the standard about 1 mg/m³ (for 360 l of air), MAC (NDS) 10 mg/m³ (inhalable fraction); PN-Z-04470:2015-10

Environment PN-Z-04470

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card, in full (our translation): "This standard gives a method for determining magnesium oxide (CAS no.: 1309-48-4) in workplace air using flame atomic absorption spectrometry. The method is used in checking sanitary and hygienic conditions. The lowest concentration of magnesium oxide that can be determined under the air sampling and determination conditions described in the standard is about 1 mg/m3 (for an air volume of 360 l)" (no full stop at the end on the card). We did not have the text of the standard (8 pages).

ACCORDING TO THE CIOP PROCEDURE (E. Gawęda, "Magnesium oxide – method of determination", Podstawy i Metody Oceny Środowiska Pracy 2010, no. 1(63), pp. 221–226 — read in full; the CIOP index of methods from 2000–2017 gives the year 2007 for this number, the article header — 2010). The procedure "is an amendment of the method given in standard PN-89/Z-04206/02", just as the 2015 standard replaced PN-Z-04206-02:1989; we do not claim that the standard repeats it — they differ at least in the limit of quantification. In the procedure: magnesium oxide is determined, as well as metallic magnesium and other magnesium compounds, expressed as MgO; cellulose ester membrane filter (0.85 µm), up to 720 l of air at a flow rate of up to 2 l/min (personal dosimetry) or up to 20 l/min (static measurement), filters kept in a refrigerator for up to 2 weeks; hot mineralisation with concentrated nitric acid (about 140 °C), solution in 0.1 mol/l nitric acid with lanthanum chloride, 40-fold dilution; FAAS at 285.2 nm, reducing air–acetylene flame; the magnesium result is converted to MgO with the factor 1.658. Limit of quantification 0.46 mg/m³ — in the abstract "for an air volume of 360 l", in point 1 of the procedure "for an air volume of 720 l" (a discrepancy within the article itself). Validation data: limit of quantification 0.06 µg/ml, correlation coefficient 1.0000, overall precision 6.6 %, overall uncertainty 16.5 %. The procedure gives the NDS values of that time: fumes 5 mg/m³, dusts 10 mg/m³.

NDS VALUE (list in the annex to the regulation of 26 March 2026, Journal of Laws 2026 item 447). Item 527: "Magnesium oxide [1309-48-4] – inhalable fraction" — NDS 10 mg/m³, no NDSCh; the inhalable fraction is defined according to PN-EN 481 (footnote 6 of the list). The list has no separate value for fumes. The lowest determinable concentration according to the card, about 1 mg/m³, is about 10 % of the NDS.

STATUS (card as of 04.10.2026). The card of PN-Z-04470:2015-10 (Polish version) has no "Withdrawn" heading and no "Withdrawal date" row: published 02-10-2015, 8 pages, price group D, Health, Environment and Medicine Sector, KT 159 Chemical and Dust Hazards in the Working Environment, ICS 13.040.30, "Replaces PN-Z-04206-02:1989". The PKN search for "PN-Z-04470" (04.10.2026) returns only this standard. The replaced PN-Z-04206-02 is not cited by any laboratory in the database copy or in the current PCA documents.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data load up to 17.09.2026, read on 04.10.2026). The number 04470 appears in 6 records at 6 laboratories; in the current PCA documents (read on 03.10.2026; issues from 08.01.2026 to 28.07.2026) — in 6 rows at the same laboratories; a search of all PCA documents downloaded from the BIP found no laboratories outside the database copy; no item is suspended and no document repeats pages. All entries have the form "PN-Z-04470:2015-10": AB 632 — next to instruction IB-13 edition 7 of 01.10.2023; AB 719 — "PN-Z-04470:2015-10 pkt 7" next to procedure PA-29 edition 18 of 30.01.2026 "excluding pt. 3.6". The "Laboratories" tab (query "PN-Z-04470") shows all 6 laboratories — checked with the tab's query on the production server labcoda.pl on 04.10.2026.

WHAT THE LABORATORIES TEST (database copy). Object: working environment — air, samples collected on filters. Quantity: concentration (content) of magnesium oxide, inhalable fraction — at all 6 laboratories (at AB 418 within the group item "content and concentration of metals and their compounds"). Ranges in mg/m³: 0.004–20 (AB 481), 0.0057–11.5 (AB 418), 0.0480–23.70 (AB 1144), 0.46–19.3 (AB 632), 0.47–22.7 (AB 1642); AB 719 — 0.00010–10.0 mg per sample. Technique: flame atomic absorption spectrometry (FAAS) — 5 laboratories; AB 719 — inductively coupled plasma atomic emission spectrometry (ICP-OES).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — limit of quantification: according to the card the lowest concentration determinable by this method is about 1 mg/m³ for 360 l of air; all laboratories with a range in mg/m³ state a lower bottom limit (from 0.004 to 0.47 mg/m³) — the bottom limits of AB 632 (0.46) and AB 1642 (0.47) are close to the limit of quantification of the CIOP procedure; a lower limit requires conditions different from those in the standard, and the report should name them. Second — what is counted as magnesium oxide: according to the CIOP procedure magnesium is determined and converted to MgO, including that from metallic magnesium and other magnesium compounds; whether the standard provides the same, WE DO NOT GIVE. Third — fraction: the NDS concerns the inhalable fraction, and a result without a defined fraction is not comparable with it. Fourth — technique: AB 719 determines magnesium by ICP-OES and cites only point 7 of the standard.

WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the volume or flow rate of air sampling, the type of filter and sampler, the mineralisation method, the wavelength, measurement conditions or calculations according to the standard; data from the CIOP procedure are given as data of the procedure.

Method principle

Magnesium oxide in workplace air is determined by flame atomic absorption spectrometry; the result in mg/m³ is compared with the NDS of 10 mg/m³ for the inhalable fraction. Lowest determinable concentration according to the card — about 1 mg/m³ for 360 l of air. WE DO NOT GIVE details of the standard — we did not have its text; the CIOP procedure of 2010 (membrane filter, nitric acid mineralisation, FAAS as magnesium) is described separately.

Applications

• Workplace air — magnesium oxide, inhalable fraction — in the current scopes of 6 laboratories
• Assessment of occupational exposure against the NDS of 10 mg/m³ for the inhalable fraction (Journal of Laws 2026 item 447, item 527 of the list)

Key parameters

Standard

Standard number

PN-Z-04470:2015-10

Title (PL)

Ochrona czystości powietrza — Oznaczanie tlenku magnezu na stanowiskach pracy metodą płomieniowej absorpcyjnej spektrometrii atomowej

Title (EN)

Air purity protection — Determination of magnesium oxide at workplaces by flame atomic absorption spectrometry

Step-by-step procedure

1. Sampling

   Air through a filter; WE DO NOT GIVE the parameters of the standard (in the CIOP procedure up to 720 l).

2. Mineralisation

   In the CIOP procedure — hot, with concentrated nitric acid; solution in 0.1 mol/l nitric acid with lanthanum chloride.

3. Measurement

   Flame atomic absorption spectrometry (PKN card); in the CIOP procedure magnesium at 285.2 nm.

4. Result and assessment

   MgO concentration in mg/m³; comparison with the NDS of 10 mg/m³ for the inhalable fraction (Journal of Laws 2026 item 447); lowest determinable concentration about 1 mg/m³ for 360 l.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Concentrated nitric acid and acetylene flame — according to the CIOP procedure, work with concentrated acids is done in protective clothing and in a fume hood
• TECHNICAL NOTE: the NDS concerns the inhalable fraction; a bottom limit below about 1 mg/m³ requires conditions different from those in the standard

Frequently asked questions