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The growing use of nanomaterials requires the development of tools enabling study of the risks to consumer, worker, and environment. This study relates to the risk of suspension of inhalable particles upon production and/or use of powders constituted of nanoobjects, and more specifically to the potential of the vortex shaker as apparatus for determining the dustiness of a powder and as atmosphere generating tool for experimental toxicology. The powder chosen for this study was Graphistrength C100 (ARKEMA), a multiwalled carbon nanotube. Its agitation in a vortex shaker at 1500 rpm leads to an aerosol divided into four families, from isolated fibres to micronic pellets. The study highlights that the speed of agitation and the geometry of the device are influential parameters, to be systematically taken into account. It concludes that while the technique seems mature to conduct C100 dustiness tests, developments are still necessary to use it routinely for toxicology studies.

The adverse health impact of particles and ultrafine particles (UFP) is proven, highlighting the need of measuring the particle number concentration (PNC) dominated by UFP. So far, PNC had never been measured in the Strasbourg urban area (France). The present study on particle size distribution and PNC measurements by an UFP-3031 analyzer was conducted during winter 2019 on a background and a roadside multi-instrumented sites (Black Carbon, chemical speciation, particulate matter 10 μm or less in diameter—PM10 mass). This paper shows significantly higher particle number concentrations of particles below 100 nm at the traffic site compared to the background site. The presence of a road axis thus mainly influences UFP, contrary to larger particles whose levels are more homogeneous over the agglomeration. During the measurement period, the nature of the particles (particle size contribution and chemical composition) was different between periods of high PM10 mass concentrations and periods of high PNC. High PM10 mass concentrations were associated with a high contribution of particles larger than 100 nm but they did not show specific chemical signature. On the other hand, during the periods with high PNC, the chemical composition was modified with an increase of the primary carbonaceous fraction compared to the periods with low PNC, but there was then no clear change in size distribution. Overall, this study illustrates that PM10 mass concentrations were barely representative of UFP and PNC variations, confirming that the monitoring of the latter metrics is necessary to better evaluate the particles toxicity, knowing that this toxicity also depends on the particle’s chemical composition.

Limonene is a widely employed Volatile Organic Compound (VOC) in scented products used in indoor environments such as household cleaners. Besides, ozone concentration, influenced by outdoor concentration and indoor sources, can be quite important to initiate gas phase chemistry and to possibly lead to SOAs formation in indoor environment. This work investigates the formation of SOAs from limonene ozonolysis in indoor conditions. It combines simulation chamber ozonolysis experiments and field studies in an experimental house allowing reproduction of real conditions for household products use situations. To search for limonene oxidation tracers, a new analytical approach is employed. Both gas and particulate phases are simultaneously collected, respectively on sorbent tubes and filters, and molecular composition is investigated using PFBHA and MTBSTFA derivatisation prior to thermal-desorption coupled with gas chromatography and mass spectrometry (TD-GC-MS) analysis. The field campaign was achieved in the experimental house MARIA especially designed for indoor air problematic studies. Experiments were performed following scenario of limonene containing household product use in realistic conditions. Limonene concentrations and particles formation and growth were observed consequently to the use of house cleaning product. Chemical characterization of both gas and particulate phases allowed identification of limonene ozonolysis tracers, such as limononaldehyde, limonaketone or ketolimonic acid. Therefore, the methodology employed allowed for the particle formation attribution to the ozonolysis of the emitted limonene, detected compounds toxicity evaluation. This study provides an insight into particle exposure and sources reduction in real indoor atmosphere.