Atmospheric Chemistry Program Seminar: Prof. Matthieu Riva, University of Helsinki

Molecular-level perspectives on atmospheric chemistry: analytical advances, from urban environments to the Arctic

Dr. Matthieu Riva,
University of Helsinki

Monoterpenes (MT) are among the most important secondary organic aerosol (SOA) precursors, influencing aerosol formation from remote forests to polluted cities. Constraining their contribution to global SOA requires analytical tools that follow their oxidation products in both the gas and particle phases. A chemical ionization Orbitrap mass spectrometer (CI-Orbitrap), combined with a particle evaporator interface (WALL-E), and a dual-inlet configuration, now enables simultaneous gas- and particle-phase measurements and provides new constraints on volatility and gas–particle partitioning. In urban centers, changing emission patterns has revealed a growing influence of MTs, which redefines how we think about SOA formation potentials in these environments. To investigate how changes in emission sources affect SOA formation, laboratory experiments were conducted to study the role of chirality, and field measurements were done to distinguish biogenic versus anthropogenic MT contributions to observed emissions in the Paris metropolitan area (MONALISA). IIn contrast to this, recent laboratory work that investigates how a changing climate may alter volatile organic compound emissions and the potential for SOA formation from permafrost and active layer samples collected in the remote Arctic will be presented. This is in preparation for upcoming field deployments where in situ measurements will be made in Spring-Summer 2027.