The project nanoGRAVUR (BMBF, 2015–2018) developed a framework for grouping of nanomaterials. Different groups may result for each of the three distinct perspectives of occupational, consumer and environmental safety. The properties, methods and descriptors are harmonised between the three perspectives and are based on: Tier 1 intrinsic physico-chemical properties (what they are) or GHS classification of the non-nano-form (human tox, ecotox, physical hazards); Tier 2 extrinsic physico-chemical properties, release from nano-enabled products, in vitro assays with cells (where they go; what they do); Tier 3 case-specific tests, potentially in vivo studies to substantiate the similarity within groups or application-specific exposure testing. Amongst all properties, dissolution and transformation are least modulated by different nanoforms within one substance, whereas dustiness, dispersion stability, abiotic and especially in vitro surface reactivity vary more often between different nanoforms. The methods developed or selected by nanoGRAVUR fill several gaps highlighted in the ProSafe reviews, and are useful to implement (i) the concept of nanoforms of the European Chemicals Agency (ECHA) and (ii) the concept of discrete forms of the United States Environmental Protection Agency (EPA). One cannot assess the significance of a dissimilarity, if the dynamic range of that property is unknown. Benchmark materials span dynamic ranges that enable us to establish bands, often with order-of-magnitude ranges. In 34 case studies we observed high biological similarity within each substance when we compared different (nano)forms of SiO₂, BaSO₄, kaolin, CeO₂, ZnO, organic pigments, especially when we compared forms that are all untreated on the surface. In contrast, different Fe₂O₃ or TiO₂ (nano)forms differ more significantly. The same nanoforms were also integrated in nano-enabled products (NEPs) for automotive coatings, clinker-reduced cements, cosmetic sunscreen, and lightweight polymers.

Existing aerosol particle mass classifiers (PMCs) can classify particles having masses down to ca. half an attogram (i.e., 10⁻¹⁸ g), which corresponds to a diameter of ca. 10 nm for spherical particles with standard density (1 g/cm³). Here, we describe an improved design of such a classifier, namely, the nano-PMC, which can classify particles with masses down to 20 zeptograms (10⁻²¹ g). The response of the classifier was characterized with spherical polystyrene-latex and ammonium sulfate particles, produced by atomization and mobility classification. Measured responses were compared with predictions by a numerical trajectory-based model that considers particle diffusivity. Measurements and predictions of the mean mass of the particles penetrating the classifier agreed within experimental uncertainty (<6%). Differences in the spectrum width could be attributed to recirculation flows occurring in the classification channel. To demonstrate the capabilities of a nano-PMC, we used it in a tandem configuration with a differential mobility analyzer to determine (1) the size-dependent shape factor of cubic sodium chloride particles having diameters from 15 to 120 nm, and (2) the apparent density and mass–mobility coefficient of coalesced and aggregated silver particles generated by spark ablation. Measurements of the shape factor of the cubic sodium chloride particles show good agreement with previous observations. Coalesced silver particles exhibited an apparent density that was lower compared with that of bulk silver, suggesting a slightly non-spherical particle shape. The mass–mobility scaling exponent of aggregated silver particles determined by the measurements was 2.3 ± 0.1. Copyright 2015 American Association for Aerosol Research

Optical aerosol spectrometers have become popular for time-resolved determination of ex-posure to respirable dust in workplaces and more recently also for indoor aerosol measurements, e.g. in the context of the COVID-19 pandemic. These instruments measure the light scattered by aerosol particles as a measure of their size. Thus, in order to determine the mass concentration of respirable dust from the instrument output, assumptions are required regarding particle properties, particularly the refractive index and density. For the determination of corona-relevant aerosols, liquid aerosol particles are of particular importance. During the investigations presented here, aerosol spectrometers from various manufacturers were challenged with different monodisperse and polydisperse, as well as solid and liquid test aerosols in the laboratory and in round robin tests. The measured values were compared with the results of reference methods. It was found that the aerosol spectrometers are generally suitable for the purposes mentioned. However, in order to obtain accurate results, it may be necessary to calibrate the instrument individually for the respective application. Optische Aerosolspektrometer werden bei der zeitaufgelösten Bestimmung der Exposition gegenüber alveolengängigem Staub (A-Staub) an Arbeitsplätzen, aber auch bei Aerosolmessungen in Innenräumen, z. B. im Zusammenhang mit der COVID-19-Pandemie, zunehmend eingesetzt. Diese Geräte messen das von Aerosolpartikeln gestreute Licht als Maß für deren Größe. Um aus den Messergebnissen z.B. die A-Staub-Massenkonzentration bestimmen zu können, sind somit Annahmen hinsichtlich der Partikeleigenschaften, insbesondere des Brechungsindizes und der Dichte, erforderlich. Für die Bestimmung coronarelevanter Aerosole sind vor allem flüssige Aerosolpartikel von Bedeutung. Im Rahmen der hier vorgestellten Untersuchungen wurden Aerosolspektrometer verschiedener Hersteller im Labor sowie in Ringversuchen mit unterschiedlichen monodispersen und polydispersen sowie festen und flüssigen Prüfaerosolen beaufschlagt und die Messwerte den Ergebnissen von Referenzverfahren gegenübergestellt. Es zeigte sich, dass die Aerosolspektrometer generell für die genannten Einsatzzwecke geeignet sind. Um möglichst genaue Ergebnisse zu erzielen, ist aber ggf. eine individuelle Gerätekalibrierung für den jeweiligen Einsatzzweck erforderlich. Optical aerosol spectrometers have become popular for time-resolved determination of ex-posure to respirable dust in workplaces and more recently also for indoor aerosol measurements, e.g. in the context of the COVID-19 pandemic. These instruments measure the light scattered by aerosol particles as a measure of their size. Thus, in order to determine the mass concentration of respirable dust from the instrument output, assumptions are required regarding particle properties, particularly the refractive index and density. For the determination of corona-relevant aerosols, liquid aerosol particles are of particular importance. During the investigations presented here, aerosol spectrometers from various manufacturers were challenged with different monodisperse and polydisperse, as well as solid and liquid test aerosols in the laboratory and in round robin tests. The measured values were compared with the results of reference methods. It was found that the aerosol spectrometers are generally suitable for the purposes mentioned. However, in order to obtain accurate results, it may be necessary to calibrate the instrument individually for the respective application. Optische Aerosolspektrometer werden bei der zeitaufgelösten Bestimmung der Exposition gegenüber alveolengängigem Staub (A-Staub) an Arbeitsplätzen, aber auch bei Aerosolmessungen in Innenräumen, z. B. im Zusammenhang mit der COVID-19-Pandemie, zunehmend eingesetzt. Diese Geräte messen das von Aerosolpartikeln gestreute Licht als Maß für deren Größe. Um aus den Messergebnissen z.B. die A-Staub-Massenkonzentration bestimmen zu können, sind somit Annahmen hinsichtlich der Partikeleigenschaften, insbesondere des Brechungsindizes und der Dichte, erforderlich. Für die Bestimmung coronarelevanter Aerosole sind vor allem flüssige Aerosolpartikel von Bedeutung. Im Rahmen der hier vorgestellten Untersuchungen wurden Aerosolspektrometer verschiedener Hersteller im Labor sowie in Ringversuchen mit unterschiedlichen monodispersen und polydispersen sowie festen und flüssigen Prüfaerosolen beaufschlagt und die Messwerte den Ergebnissen von Referenzverfahren gegenübergestellt. Es zeigte sich, dass die Aerosolspektrometer generell für die genannten Einsatzzwecke geeignet sind. Um möglichst genaue Ergebnisse zu erzielen, ist aber ggf. eine individuelle Gerätekalibrierung für den jeweiligen Einsatzzweck erforderlich. Die Gefahrstoffe ist die führende Fachzeitschrift für Luftreinhaltung, Emissionsschutz und -messung, sowie Messverfahren. Sie leistet seit Jahren Pionierarbeit und stellt daher eine Diskussionsplattform für Wirtschaft, Wissenschaft und Gesellschaft dar. Alle Beiträge vermitteln auf höchstem journalistischem Niveau Themen wie Emissionsgrenzwerte am Arbeitsplatz, Umweltmeteorologie, Innenraumluft, Biomonitoring und sicherer Umgang mit Gefahrstoffen. Sie liefert darüber hinaus Informationen zum aktuellen Regelwerk und dessen Umsetzung in die Praxis. Die Zeitschrift berichtet in fundierten Fachbeiträgen interdisziplinär über Schadstoffentstehung, -ausbreitung, -erfassung und -abscheidung, Probenahme und Messverfahren. 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Airborne micro- and nanoplastic particles (MNPs) are increasingly recognized as a potential occupational exposure hazard, yet substance-specific workplace data remain limited. This study quantified airborne MNP concentrations during polyester microfiber production using a correlative SEM–Raman approach that enabled chemical identification and size-resolved particle characterization. The aerosol mixture at the workplace was dominated by sub-micrometer particles, with PET—handled onsite—representing the main process-related MNP type, and black tire rubber (BTR) forming a substantial background contribution. Across both sampling periods, total MNP particle number concentrations ranged between 6.2 × 10⁵ and 1.2 × 10⁶ particles/m³, indicating consistently high particle counts. In contrast, estimated MNP-related mass concentrations were much lower, with PM₁₀ levels of 12–15 µg/m³ and PM_2.5 levels of 1.3–1.6 µg/m³, remaining well below applicable occupational exposure limits and near or below 8 h-equivalent WHO guideline values. Comparison with earlier workplace and indoor studies suggests that previously reported concentrations were likely underestimated due to sampling strategies with low efficiency for small particles. Moreover, real-time optical measurements substantially underestimated particle number and mass in this study, reflecting their limited suitability for aerosols dominated by small or dark particles. Overall, the data show that workplace MNP exposure at the investigated site is driven primarily by very small particles present in high numbers but low mass. The findings underscore the need for substance-specific, size-resolved analytical approaches to adequately assess airborne MNP exposure and to support future development of MNP-relevant occupational health guidelines.