Publications by authors named "Michael Boy"
Article Synopsis
- Modelling atmospheric chemistry is complicated and involves intensive computations; however, the proposed ChemNNE uses Deep Neural Networks to quickly simulate chemical concentrations by treating them as time-dependent equations.
- This emulator employs an attention-based mechanism, sinusoidal time embedding for capturing periodic patterns, and a Fourier neural operator to improve efficiency and handle complex behaviors in the chemical processes.
- The model is trained with three physics-informed loss functions to adhere to conservation laws and reaction rates, and it is validated using a large-scale dataset that sets a benchmark for accuracy and speed in future research.
Article Synopsis
- Limonene, often found in personal care and cleaning products, is becoming a significant indoor air pollutant linked to increased reactive chlorine species during disinfecting processes.
- The study explores how chlorinated limonene peroxy radicals (Cl-lim-RO•) react, shedding light on their transformation products and the potential for forming hazardous secondary organic aerosols.
- Findings reveal that these transformation products are more toxic than limonene itself, raising health concerns for people exposed to both cleaning agents and disinfectants.
In the last few decades, atmospheric formation of secondary organic aerosols (SOA) has gained increasing attention due to their impact on air quality and climate. However, methods to predict their abundance are mainly empirical and may fail under real atmospheric conditions. In this work, a close-to-mechanistic approach allowing SOA quantification is presented, with a focus on a chain-like chemical reaction called "autoxidation".
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- - Understanding the formation of secondary organic aerosols (SOA) at a molecular level is challenging due to unclear mechanisms and inadequate analytical methods, particularly in developing countries where haze impacts climate and health significantly.
- - This study includes simultaneous measurements of volatile organic compounds (VOCs), oxygenated organic molecules (OOMs), and SOA particles in Beijing, revealing that OOMs are responsible for 26-39% of organic aerosol mass growth.
- - The findings indicate that the contribution of OOMs to SOA increases during severe haze episodes, establishing a clear link from emissions to the formation of haze through condensable organic oxidation products.
Major atmospheric oxidants (OH, O and NO) dominate the atmospheric oxidation capacity, while HSO is considered as a main driver for new particle formation. Although numerous studies have investigated the long-term trend of ozone in Europe, the trends of OH, NO and HSO at specific sites are to a large extent unknown. The one-dimensional model SOSAA has been applied in several studies at the SMEAR II station and has been validated by measurements in several projects.
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- Over Boreal regions, monoterpenes are key for producing secondary organic aerosols and enhancing cloud condensation nuclei, which are important for climate.
- A new model has been created that accurately describes and predicts new particle formation and Highly Oxygenated Organic Molecules (HOM) in the atmosphere.
- The findings show that while HOM SOA formation can cool the climate by increasing CCN concentration, new particle formation can have the opposite effect, contributing to climate warming.
COSMO-RS (conductor-like screening model for real solvents) and three different group-contribution methods were used to compute saturation (subcooled) liquid vapor pressures for 16 possible products of ozone-initiated α-pinene autoxidation, with elemental compositions C10H16O4-10 and C20H30O10-12. The saturation vapor pressures predicted by the different methods varied widely. COSMO-RS predicted relatively high saturation vapor pressures values in the range of 10(-6) to 10(-10) bar for the C10H16O4-10 "monomers", and 10(-11) to 10(-16) bar for the C20H30O10-12 "dimers".
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