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Sea salt aerosol particles are highly abundant in the atmosphere and play important roles in the global radiative balance. After influence from continental air, they are typically composed of Na+, Cl–, NH4+, and SO42–and organics. Analogous particle systems are often studied in laboratory settings by atomizing and drying particles from a solution. Here, we present evidence that such laboratory studies may be consistently biased in that they neglect losses of solutes to the gas phase. We present experimental evidence from a hygroscopic tandem differential mobility analyzer and an aerosol mass spectrometer, further supported by thermodynamic modeling. We show that, at normally prevailing laboratory aerosol mass concentrations, for mixtures of NaCl and (NH4)2SO4, a significant portion of the Cl–and NH4+ions are lost to the gas phase, in some cases, leaving mainly Na2SO4in the dry particles. Not considering losses of solutes to the gas phase during experimental studies will likely result in misinterpretation of the data. One example of such data is that from particle water uptake experiments. This may bias the explanatory models constructed from the data and introduce errors inte predictions made by air quality or climate models.

This paper highlights the challenges of self-limitation, providing insights into how event sport participants relate to and act within limits. From a cultural degrowth perspective that advocates for the need to practice self-limitation and reduce environmental waste from economic activities, we examine how event participants perceive physical impacts on nature during two types of nature-based events in Jämtland, Sweden. Based on 50 semi-structured interviews, observations and photo-elicitation observations, the findings reveal the difficulties of adhering to limitations. Initially, the informants considered only trash or greenhouse gas emissions as impacts but were stunned to see photos of how impacts such as trail and soil erosion had gone beyond what they imagined. However, responsibility for limiting the effects tended to shift to others, particularly the event organisers. These two events present a paradox in tourism. The convivial idea of visiting nature collides with resource utilisation that heavily impacts the environment.

We sampled ammonium sulfate particles and indoor particles of outdoor origin through a small chamber covered with polyvinyl chloride flooring. We measured the uptake of semivolatile organic compounds (SVOCs) by the airborne particles in real time. The particles acquired SVOC mass fractions up to 10%. The phthalate ester (di(2-ethylhexyl)phthalate) (DEHP), a known endocrine disruptor, contributed by approximately half of the sorbed SVOC mass. The indoor particles acquired a higher DEHP fraction than laboratory-generated ammonium sulfate aerosol. We attribute this increased uptake to absorption by organic matter present in the indoor particles. Using a thermodenuder to remove volatile components, predominantly organics, reduced the SVOC uptake. Positive matrix factorization applied to the organic mass spectra suggests that hydrocarbon-like organic aerosol (typically fresh traffic exhaust) sorbs DEHP more efficiently than aged organic aerosol. The SVOC uptake is one of the processes that modify outdoor pollution particles after they penetrate buildings, where the majority of exposure occurs. Particles from indoor sources, typically dominated by organic matter, will undergo such processes as well. Aerosol mass spectrometry improves the time resolution of experimental investigations into these processes and enables experiments with lower, relevant particle concentrations. Additionally, particle size-resolved results are readily obtained.

Multimetallic nanoparticles possess a variety of beneficial properties with potential relevance for various applications. These metallic nanoparticles can consist of randomly ordered alloys, which retain the properties of the constituting elements, or ordered intermetallics, which possess extended properties. Depending on the desired application, specific alloys or intermetallic compounds are required. However, it remains challenging to achieve particular morphologies, crystal structures, chemical compositions, and particle sizes because of the inherent complexity of nanoparticle synthesis. In this work, Au–Sn nanoparticles were synthesized using a continuous one-step gas-phase synthesis method that offers the possibility to anneal the nanoparticles in flight directly after generation to tune their properties. The bimetallic model system Au–Sn, comprising both alloys and intermetallic compounds, was studied in the temperature range of 300 to 1100 °C. The bimetallic Au/Sn ratio in the nanoparticles can be adjusted with in-flight annealing between 70/30 and 40/60 atomic %. While Au-rich alloys are obtained at lower temperatures, the increase in the annealing temperature leads to the formation of more Sn-rich intermetallic phases. Surface and size effects greatly influence particle morphologies and phase fractions. This research opens new opportunities for the synthesis of customized nanoparticles by temperature adjustment and particle size selection.

Phthalates are ubiquitous in indoor environments, which raises concern about their endocrine-disrupting properties. However, studies of human uptake from airborne exposure are limited. We studied the inhalation uptake and dermal uptake by air-to-skin transfer with clean clothing as a barrier of two deuterium-labeled airborne phthalates: particle-phase D4-DEHP (di(2-ethylhexyl)phthalate) and gas-phase D4-DEP (diethyl phthalate). Sixteen participants, wearing trousers and long-sleeved shirts, were under controlled conditions exposed to airborne phthalates in four exposure scenarios: dermal uptake alone and combined inhalation + dermal uptake of both phthalates. The results showed an average uptake of D4-DEHP by inhalation of 0.0014 ± 0.00088 (μg kg–1bw)/(μg m–3)/h. No dermal uptake of D4-DEHP was observed during the 3 h exposure with clean clothing. The deposited dose of D4-DEHP accounted for 26% of the total inhaled D4-DEHP mass. For D4-DEP, the average uptake by inhalation + dermal was 0.0067 ± 0.0045 and 0.00073 ± 0.00051 (μg kg–1bw)/(μg m–3)/h for dermal uptake. Urinary excretion factors of metabolites after inhalation were estimated to 0.69 for D4-DEHP and 0.50 for D4-DEP. Under the described settings, the main uptake of both phthalates was through inhalation. The results demonstrate the differences in uptake of gas and particles and highlight the importance of considering the deposited dose in particle uptake studies.

Energy decay plays a central role in a wide range of phenomena, such as optical emission, nuclear fission, and dissipation in quantum systems. Energy decay is usually described as a system leaking energy irreversibly into an environmental bath. Here, we report on energy decay measurements in nanomechanical systems based on multilayer graphene that cannot be explained by the paradigm of a system directly coupled to a bath. As the energy of a vibrational mode freely decays, the rate of energy decay changes abruptly to a lower value. This finding can be explained by a model where the measured mode hybridizes with other modes of the resonator at high energy. Below a threshold energy, modes are decoupled, resulting in comparatively low decay rates and giant quality factors exceeding 1 million. Our work opens up new possibilities to manipulate vibrational states, engineer hybrid states with mechanical modes at completely different frequencies, and to study the collective motion of this highly tunable system.