New particles form in the atmosphere and can influence the climate. We studied Arctic new particle formation (NPF) from 2022 to 2024 at the Zeppelin Observatory, on Svalbard. NPF occurs from April to November, peaking in late spring as sunlight increases. Some particles measured on-site grow large enough to seed clouds. Sunlight and existing aerosol particles strongly impact the likelihood of NPF, which mainly originates from marine regions, particularly the Greenland Sea.

Aerosols, a large uncertainty in climate modeling, can be formed when gas vapors and particles begin sticking together. Traditionally, these particles are assumed to behave like hard spheres that only stick together upon head on collisions. In reality, particles can attract each other over distances, leading to more frequent sticking events. We found that traditional models significantly undercount these events, with real sticking rates being up to 2.4 times higher.

This study evaluates the performance of energy-dispersive X-ray fluorescence (ED-XRF) on particulate matter (PM₁₀) samples collected on quartz and Teflon filters through an inter-laboratory comparison. Detection limits were higher on quartz, but measurement repeatability was similar. Strong elemental correlations suggest that, with proper corrections, quartz filters can provide reliable results. These findings support their feasibility for ED-XRF analysis.

The concept of mean free path is fundamentally important to aerosol studies. Recent studies suggested that the mean free path of air (λ_air) could have been significantly overestimated by a factor of ~2. Here we show that this potential overestimation does not directly affect collisions-induced aerosol dynamics in atmospheric conditions without a high excess latent heat, because the collision rate is determined by the effective mean free path for vapor and particle collisions rather than λ_air.

Aerodyne aerosol mass spectrometer (AMS) is widely used to quantitatively measure the chemical compositions of aerosols in the atmosphere. This work presents a comprehensive analysis of the newly developed aircraft inlet system for AMS and tools for aerosol beam diagnostics to minimize particle losses. When the particle beam is properly monitored and aligned, the new inlet system can be operated at higher altitudes while sampling a wider size range of particles than previous versions.

New particle formation (NPF) is a process of forming new aerosol particles in the atmosphere. It was widely studied in boreal forest areas in Finland and Estonia; but its features and precursors in Siberian boreal forest remained unclear. We did a comprehensive analysis using data from state-of-art instruments and implement both traditional and new methods of data analysis. Understanding these processes helps us grasp how Siberia’s atmosphere evolves and contributes to global climate dynamics.

Particle formation rate is one of the key factors to study the physical properties of aerosols, because it is still not entirely clear how particles form under different environmental conditions. By developing powerful and simple particle formation rate models, we can predict how many atmospheric particles are produced, and compare it with the real-time measurement to help with the scientists on discovering more hidden particle formation mechanisms.

Metal nanoparticles (Au, Pt, Cu and Ni) were generated in the aerosol phase using spark ablation and analysed for size, shape and number concentration. Particles as small as 1 nm and up to > 60 nm show shapes from fully spherical to fractal-like as characterized by electron microscopy. Furthermore, the metal particles were mixed with TiO₂ nanoparticles and the number and size of metal particles coating the TiO₂ were determined.

We present continuous ice-nucleating particle data that were measured in the Alaskan Arctic from Oct. 2021 to Dec. 2023. We found a greater efficiency in the arctic immersion freezing during autumn compared to those found previously at two mid-latitude sites, as well as profound freezing efficiencies in spring, presumably due to arctic haze events. Our study will be useful to improve atmospheric models to simulate cloud feedback and determine their impact on the global radiative energy budget.

This study examines the deliquescence behavior of NaCl particles in a turbulent humidity field using the wind tunnel LACIS-T. The results show turbulent relative humidity (RH) fluctuations affect the number of deliquesced particles, depending on mean RH, strength of humidity fluctuations, and particle residence time. It turns out that, in addition to the mean RH, it is essential to consider humidity fluctuations and particle history when determining the phase state of the deliquescent particles.

Acyl peroxy radicals can act as atmospheric oxidants of unsaturated hydrocarbons if their 1) unimolecular reactions are slow and 2) bimolecular accretion reactions are fast. Using theoretical tools, we show which acyl peroxy radicals should be considered as oxidants in the atmosphere.

We investigated the sources of ultrafine particles (UFPs) in Payerne, Switzerland, highlighting the significant role of secondary processes in elevating UFP concentrations to levels comparable to urban areas. As the first study in rural midland Switzerland to analyze new particle formation events and secondary contributions, it offers key insights for air quality regulation in Switzerland and central Europe.

Quantification of autoxidation chemistry is a complex task, essential to our understanding of atmospheric secondary aerosol formation and its impact on climate. In this work, we introduce the autoCONSTRAINT module, a semi-empirical method to deduce reaction rate coefficients for lumped autoxidation chemistry schemes based on experimental data. The theoretical approach is analytical and provides mathematically correct, though non-unique, solutions with low computational cost.