Preprints  

Ambient ice-nucleating particle (INP) concentrations were measured in Israel, which experiences air masses from a variety of sources. We found that the INP activity is typically dominated by K-feldspar mineral dust, but that air masses passing over the Fertile Crescent region correlated with high INP concentrations and indicators of biological activity. This suggests that the Fertile Crescent could be a sporadic source of warm-temperature biogenic INPs, and warrants further study of the region.

More than 35'000 particle counters designed for the periodic technical inspection of diesel engine exhaust have been placed on the European market in the past few years. This work shows that the counting efficiency of these instruments depend on the properties of the test aerosols, even if all of them are combustion-based soot of similar mobility diameter. The aim of this study is to promote harmonisation of measurement procedures in the field of emission control.

We present a novel version of a aerosol number size distribution instrument, showcasing its capability to measure particle number concentration and particle number size distribution between 1 and 12 nanometers. Our results show that the instrument agrees well with existing instrumentation and allows both for the accurate measurement of the smallest particles as well as providing overlap with more conventional aerosol number size distribution instruments.

Although spray flame synthesis (SFS) is a promising approach to prepare nano materials with tailored properties, the impurity formation is not fully understood in SFS. To contribute to this topic, maghemite nanoparticles were prepared by SFS, and two complementary experimental approaches were used to investigate the evolution of soot and carbonaceous surface adsorbates. The methodological procedure and the data provided can be used to denote/compare SFS-materials more reliably in the future.

Aircraft are an important source of both soot aerosols and pollutants such as CO₂ and nitrogen oxides (NOx) which also negatively affect human health and the environment. In many cases, strategies to reduce one pollutant may increase another. So, it is vital to have a quantitative understanding of the contribution of each pollutant to negative outcomes so that trade-offs can be made. Here, we review methods to reduce aircraft soot emissions through the use of fuel, engine design and operation.

We analyse the mechanism whereby sunlight and iron catalyse the production of chlorine from chloride in sea spray aerosol. This process occurs naturally over the North Atlantic and is the most important single source of chlorine. We investigate the mechanism using quantum chemistry, laboratory experiment and aqueous chemistry modeling. The process will change depending on competing ions, light distribution, acidity and chloride concentration.

Several papers have reported on electrospray technique and they have shown that uniform thin films with different surface morphologies can be deposited. Nonetheless, the studies do not give a systematic way of designing different surface morphologies and most outcomes are based on a trial-and-error method. Therefore, in this study a systematic way of designing thin films of different surface morphologies using electrospray technique has been developed.

Minuscule airborne carbon particles impact climate and health, but measuring them poses many challenges. We developed FATCAT to fill this gap. FATCAT measures carbon particles continuously and unattended over extended periods of time. We detail FATCAT's performance, demonstrate its agreement with established methods and introduce a novel and unique aspect: fast thermograms. These thermograms are related to particle composition and can potentially be used to identify pollution sources.

The performance of a Partector Pro has been evaluated against a reference in a 70-day measurement campaign at an urban background site in Germany. The Partector Pro delivered reasonably accurate representations of the size distributions for particle sizes below 114 nm, but higher discrepancies for larger sizes. The number concentration was accurately determined by the Partector Pro (slope 0.998, R² = 0.996) and the results for the mean particle size agreed with the reference mostly within ±15 %.

This study illustrates the feasibility of determining the ultraviolet (UV) dose experienced by aerosol droplets without the use of virus-containing aerosols. A model system consisting of non-evaporating droplets loaded with UV-sensitive dyes was developed. Dye-containing aerosol droplets were generated and then exposed to UVC light in a labor-built irradiation chamber. This approach is crucial for a faster and more comprehensive understanding of bioaerosol inactivation using UVC radiation.

Differential mobility analyzers (DMAs) are widely used to measure aerosols size distributions. Here we argue that DMAs operating steadily at unusually high flow rates are not as complex as they appear, and could be used with considerable advantage in many measurements currently carried out in conventional DMAs. We hope that the considerations presented will encourage DMA manufacturers to develop high flow DMAs far more versatile yet comparable in complexity to today’s mainstream instruments.

We introduce a novel method for evaluating days when small particles are formed in the atmosphere. Instead of the traditional binary division between event and non-event days, our method, known as "Nano Ranking Analysis," provides a continuous, non-categorical metric for each day. By utilizing data from Hyytiälä, Finland, we show that our approach effectively quantifies these events. This innovative method paves the way for a deeper understanding of the factors influencing particle formation.