Swiss Made Measurement Techniques for Carbonaceous Aerosols

Abstract

Carbonaceous aerosols (CA) represent a chemically and physically diverse class of airborne particles. Their relevance for climate and health is significant, but poorly understood. Conventional metrics, such as particulate matter (PM₁₀ or PM_2.5), are insufficient to capture their impact. More specific indicators, such as elemental and organic carbon (EC and OC) and equivalent black carbon (eBC), often suffer from methodological artefacts, limited compatibility, and insufficient time resolution. In this work, we present an overview of the techniques and measurement systems developed by members of our group at FHNW for improved in situ quantification and characterization of CA. Photoemission-based sensors provide a real-time signal that serves as a proxy for particle-bound polycyclic aromatic hydrocarbons (PAHs), which include well known carcinogenic substances. Photothermal methods, such as photothermal interferometry (PTI) and photoacoustic spectroscopy (PAS), are used for direct observation of light absorption — an optical property directly linked to climate effects — without artefacts inherent to filter-based measurements. The fast thermal carbon totalizator (FATCAT) provides robust, unattended measurement of total carbon with high time resolution and generates fast-thermograms that reveal volatility and refractivity. Collectively, these methods address key limitations of current CA monitoring and support the long-term goal of integrating relevant metrics into air quality monitoring and climate observation networks.