Publications by authors named "Lauri R Ahonen"
Highly oxygenated organic molecules (HOMs) are important sources of atmospheric aerosols. Resolving the molecular-level formation mechanisms of these HOMs from freshly emitted hydrocarbons improves the understanding of aerosol properties and their influence on the climate. In this study, we measure the electrical mobility and mass-to-charge ratio of α-pinene oxidation products using a secondary electrospray-differential mobility analyzer-mass spectrometer (SESI-DMA-MS).
View Article and Find Full Text PDFAerosol particles negatively affect human health while also having climatic relevance due to, for example, their ability to act as cloud condensation nuclei. Ultrafine particles (diameter < 100 nm) typically comprise the largest fraction of the total number concentration, however, their chemical characterization is difficult because of their low mass. Using an extractive electrospray time-of-flight mass spectrometer (EESI-TOF), we characterize the molecular composition of freshly nucleated particles from naphthalene and β-caryophyllene oxidation products at the CLOUD chamber at CERN.
View Article and Find Full Text PDFA major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NO ) and sulfur oxides (SO ) from fossil fuel combustion, as well as ammonia (NH) from livestock and fertilizers.
View Article and Find Full Text PDFArticle Synopsis
- Nucleation and growth of aerosol particles from atmospheric vapors are important for forming cloud condensation nuclei (CCN), particularly for particles smaller than 10 nm that face significant losses from coagulation.
- Recent findings indicate that oxidation products from biogenic volatile organic compounds are key to particle formation and initial growth; however, the role of these oxidized organics in particle growth across various temperatures remains uncertain.
- Experiments conducted in the CLOUD chamber at CERN reveal that organic particle growth occurs across a broad temperature range, with growth rates influenced by particle curvature and supported by a gas-phase model of oxidized organic molecules.
Solar eclipses provide unique possibilities to investigate atmospheric processes, such as new particle formation (NPF), important to the global aerosol load and radiative balance. The temporary absence of solar radiation gives particular insight into different oxidation and clustering processes leading to NPF. This is crucial because our mechanistic understanding on how NPF is related to photochemistry is still rather limited.
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