European Ecodesign regulation underestimates a major part of the total aerosol at the stack during domestic wood combustion because the condensable fraction (CF) is not taken into account. This study presents a new experimental methodology to quantify CF. The condensable fraction accounts for 50 % at minima of the total concentration of particulate emissions. This is an important result that needs to be included in future experimental protocols of the total aerosol.

We developed a regression model to predict particle number concentrations across size ranges using meteorological variables and trace gases at SMEAR stations in Helsinki, Hyytiälä, and Värriö. The model performed well and captured diurnal and seasonal variability. Five scenarios showed that training data selection, recency, and duration influence performance, with limited benefits from older data. These findings guide training data selection and support future forecasting.

Some particles emitted from the Earth’s surface can modify clouds by triggering ice formation, so called ice nucleating particles (INPs). We estimate the flux of biological INPs from the source region of a high-altitude site by applying two new implementations of a method originally developed to determine greenhouse gas fluxes. Initial estimates suggest that transport on fair-weather summer days only makes a relatively small contribution to the annual export of biological INPs above the Alps.

This study investigated fine particulate air pollution across five Greek cities to identify its primary sources. By chemically analyzing over 545 24-hour air filter samples, we mapped seasonal patterns and identified seven major emission sources. Marked differences show that while regional background pollution strongly affects PM_2.5 levels, local activities, particularly winter wood burning for residential heating, remain a primary cause of urban air degradation in Greece.

Vehicle exhaust contains ultrafine soot particles that can harm health and the environment. Particle number measurements are essential because these particles contribute little to particulate mass. PTB developed a calibration facility producing stable soot particles of defined sizes for testing particle counters. Instruments are compared with a reference linked to national standards. The facility improves measurement accuracy and comparability between laboratories and supporting authorities.

In this study, indoor and outdoor pollutant concentrations were measured in a mechanically ventilated building in the immediate vicinity of a busy international airport. The measurement period included a strong long-range transport event. Clear differences in indoor outdoor ratios were observed between different pollutants and between normal and long-range transport periods. This study highlights the significance of a intake filtration system in indoor pollutant concentration management.

We retrieve refractive indices of laboratory-generated soot from measured particle properties using Mie and RDG-FA optical calculations, and quantify uncertainties via Monte Carlo simulations. The inferred refractive indices strongly depend on the theory employed, highlighting the need for consistency between optical theory and refractive index. Mie retrievals are sensitive to coagulation and size growth, while RDG-FA retrievals depend strongly on the uncertainty of assumed particle morphology.

Typical MPSS measurements rely on bipolar diffusion charging, where the steady-state particle charge distribution depends on charger ion properties. By simultaneously measuring ion properties and particle charge fractions, we show that Hoppel&Frick theory accurately describes charging of sub-20 nm particles. By introducing siloxanes via outgassing from conductive silicone tubing, we further show that ion properties, and thus particle charge distributions, are sensitive to trace-gas composition.

Urban street canyon measurements during spring showed that submicron particles (PM₁) dominated light absorption and black carbon from traffic exhaust, while coarse particles (PM_2.5–PM₁₀) became important during dust resuspension events. Size-resolved optical and chemical analyses revealed strong source-dependency, with coarse fractions influencing absorption metrics and source apportionment, especially during street dust events, which highlighted the importance of selected particle size cut-off.

Wood burning is seen as cleaner in modern stoves, but user behaviour can change this when burning dry wood. We burned dry ash wood in a UK modern stove with six common operations and measured the wood smoke. Reloading while hot, using too much or too little wood, or opening the stove door increased small particels and harmful smoke emissions. We found a burning stage that helps explain these emissions. Using big pieces of wood and following guidance can reduce pollution and health risks.

Exhaust from a Euro 6 compressed natural gas taxi was tested under simulated real-world driving, including different driving dynamics and operating conditions. Diluted exhaust was used to expose human lung cells. Although particle mass was low, cell viability was reduced, cell damage was increased, and inflammatory responses were triggered. The findings show that health relevance depends on several emission properties, not particle mass alone.

Combusting hydrogen alongside carbon-based fuels has been proposed to reduce CO₂ emissions. In this work, we investigate how this affects the emitted particles, using a model flame. Increasing hydrogen leads to smaller particles containing a higher of organic material and less of the of the strongly light absorbing elemental carbon. However, the organic material shows considerable light absorption at shorter visible wavelength and in the UV.

The study aimed to mimic the atmospheric behaviour of a semi-volatile organic compound in the presence of fine particles and at various relative humidities. The objective was to determine the influence of organic matter on humid particle growth. These results are essential for improving our understanding of cloud formation.

Atmospheric new particle formation (NPF) is crucial for aerosol number concentration. Recent methodologies propose that “quiet” NPF (QNPF) events, which are not traditionally classified as NPF, can contribute significantly to aerosol number. This study presents three-years of observations of ion and particle size distributions at the Finokalia station in Eastern Mediterranean. It shows that QNPF events are frequent providing fundamentally new understanding of NPF processes in the region.

Organic aerosols influence global climate though uncertainties in the magnitude of this influence remain large. A comprehensive understanding of the molecular composition of aerosols is key to minimizing these uncertainties. We present a new method for analyzing organic aerosols in real time using ion mobility mass spectrometry, enabling the separation of aerosol components with identical mass. Analysis of standards and laboratory-generated aerosols demonstrate the method’s potential.