Atmospheric Mass Spectrometry

We focus on developing and deploying state-of-the-art mass spectrometric techniques for gas and aerosol particle analysis. Research interests span volatile (mainly organic) emissions, atmospheric oxidants and oxidation products, small molecular clusters, as well as larger aerosol particles.

Core research areas currently include

  • - Volatile organic compounds (VOCs): Understanding the biosphere-atmosphere exchange of VOCs and their atmospheric behavior, especially in the boreal regions.
  • - Atmospheric oxidants: The relative importance of the hydroxyl radical (OH) and stabilized Criegee intermediates for the oxidative capacity of the atmosphere.
  • - Organic oxidation products: Semi-, low- and extremely low-volatility organic compounds (SVOC, LVOC, ELVOC) contribute to secondary organic aerosol (SOA), which forms a major fraction of atmospheric aerosol particle mass. The relative roles of these species in SOA formation and growth of newly formed particles governs the final amount of particles available to act as cloud condensation nuclei (CCN), thereby affecting Earth's climate
  • - Aerosol particle precursors vapors and clusters: In addition to ELVOC, sulfuric acid, ammonia, amines and iodide oxides are examples of vapors that we have measured in direct relation to cluster formation and new particle formation in laboratory and field observations.
  • - Aerosol particle composition: The composition of particles larger than about 50 nm is influenced by both local sources as well as long-range transport in the atmosphere. The concentration and composition of these particles governs the amount of directly available CCN, but also strongly influences how new particles are able to form.

The figure above, adapted from Ehn et al. (2014), Nature, provides an overview of our current understanding of emissions, their reactions with different oxidants, and the pathways through which they contribute to aerosol formation and growth, ultimately producing particle large enough to be able to affect the climate. Many findings leading to this understanding is based on mass spectrometer data from our group.

Group website