In this study, we explored how tiny particles in the air, known as aerosols, have changed over time in two mountainous areas in Austria and Switzerland from 2007 to 2023. By using special instruments that measure sunlight, we tracked these changes and found that the amount of aerosols has been decreasing in both locations. This is important because aerosols can affect both our health and the climate. This work is crucial for understanding air quality trends in mountain environments.

Our study presents a novel method for quantifying mass spectrometer responses to molecular species in organic aerosols. Traditional calibrations often fail for complex mixtures like secondary organic aerosol. We combined chromatography with statistical component analysis to improve separation and quantification, achieving promising agreement with direct calibration. Our findings offer a new approach to assess aerosol composition, especially beneficial for complex mixtures.

Differential mobility analyzers (DMAs) are widely used to measure aerosol 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 present a novel version of an aerosol number size distribution instrument, showcasing its capability to measure particle number concentration and particle number size distribution between 1 and 12 nm. Our results show that the instrument agrees well with existing instrumentation and allows for both the accurate measurement of the smallest particles and overlap with more conventional aerosol number size distribution instruments.

The manuscript highlights that the composition dependence of the counting efficiency of condensation particle counters can be immensely reduced by choice of the working fluid. A butanol- and a propylene glycol-based version of the Airmodus A30 was calibrated using a set of four different seed particles. Our study shows that composition-dependent counting efficiencies almost vanish in case of the propylene glycol-based CPC. Simulations of supersaturation profiles were used to explain the results.