We evaluated dimethyl sulfoxide as a safe, non-flammable working fluid for condensation particle counters, comparing it with butanol under varied pressures, temperatures, and aerosols. Laboratory, field, and simulation results show reliable particle activation, comparable counting efficiency, reduced fluid use, and stable long-term operation. Mixtures with water extend usability, supporting safe monitoring in remote or harsh environments.

Parasitic direct currents in our alternating-current power grid affect the operation of power transformers. In this work, we present a fiber-optic current sensor system designed for the long-term monitoring of such direct currents, especially those arising from solar activity. The sensor demonstrator allows remote data access and sensor operation and was deployed at an electrical substation. For the first time, we show measurements of such currents on single phases of the power grid.

This study presents a new method to measure ultrafine airborne particle concentrations down to 3 nm at high concentrations. By growing the particles into droplets, subsequently electrically charging them, and detecting the electrical signal, the system enables accurate and compact measurements of the particle number concentration. This approach is useful for onboard monitoring of vehicle emissions where space is limited and high concentrations are measured.

Exhaust emissions from combustion-based vehicles are negatively affecting human health and our environment. In particular, a small share (< 20 %) of poorly maintained or tampered vehicles are responsible for the majority (60 %–90 %) of traffic-related emissions. The emissions from vehicles are currently not properly monitored during their lifetime. We present a roadside measurement technique, called point sampling, which can be used to monitor vehicle emissions throughout their life cycle.

This work describes the design, calibration, and application of a hygrometer and sampling system, which have been developed and used for water content measurement in experimentally simulated atmospheric icing conditions with relevance in fundamental icing research as well as aviation testing and certification. Together with a general description of water content measurement and accompanying uncertainties, the results of a comparison to reference instruments in an icing wind tunnel are presented.