Michela Sega

Metrological traceability for benzo[ a ]pyrene quantification in airborne particulate matter

Airborne particulate matter (PM) represents one of the most important sources of urban pollution due to its physical and chemical properties. There is a great concern for PM dangerous effects on human health because particles can deeply penetrate into the respiratory system, carrying the contaminants adsorbed onto their surface. Polycyclic aromatic hydrocarbons (PAHs) are a class of organic contaminants that can be adsorbed onto PM and can have harmful effects on health, due to their particular chemical structure. The International Agency for Research on Cancer (IARC) classified PAHs as potential carcinogenic agents and benzo[a]pyrene (BaP) as carcinogenic to humans. In this paper, the development of a metrologically traceable procedure for the quantification of BaP in airborne PM, performed at the Italian National Institute of Metrological Research (Istituto Nazionale di Ricerca Metrologica—I.N.Ri.M.), is presented. The identification and quantification of BaP in PM samples were carried out by gas chromatography coupled with mass spectrometry (GC–MS). Metrological traceability was established in all the procedure steps, after performing the method validation. Suitable certified reference materials (CRMs) were used both to validate the analytical method and to calibrate the GC–MS. The measurement uncertainty was evaluated by identifying and taking into account all the relevant sources deriving from the whole procedure steps.

Final report on comparison EURO.QM-S1: Automotive exhaust gas

Automotive gas mixtures of carbon monoxide, carbon dioxide, oxygen and propane in nitrogen are used for the calibration of measurement equipment for automotive exhaust gases. This comparison involved four laboratories. Two have used their own gravimetric primary standards, one of them used standards prepared by an accredited laboratory and the other used their own gravimetric primary standards together with gravimetric primary standards prepared by other national laboratories. CEM operated as the coordinating laboratory in this comparison. The selected primary gas mixtures for this comparison were individually prepared gravimetrically and thoroughly studied for their chemical composition and stability. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EUROMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Traceability in routine chemical measurements: an example of application in the determination of CO2 at atmospheric concentration

In routine chemical measurements traceability can be achieved by using analytical instruments calibrated against primary reference materials. In the present work the calibration of a CO2 nondispersive infrared (NDIR) analyzer with measuring range 0–2000 µmol/mol of CO2 and a resolution of 5 µmol/mol is reported. A procedure with working reference gas mixtures (WRMs) has been adopted, which requires seven calibration points. Primary reference gas mixtures (PRMs) are used to validate WRMs in a narrower range around the average atmospheric CO2 concentration value. In this range the relative uncertainty reached is of the order of some parts in 103 and the corrections are between 1 µmol/mol and 5 µmol/mol.