Role of Iodine-Assisted Aerosol Particle Formation in Antarctica

• Published in: Environmental science & technology Vol. 58; no. 17; pp. 7314 - 7324
• Main Authors: Xavier, Carlton, de jonge, Robin Wollesen, Jokinen, Tuija, Beck, Lisa, Sipilä, Mikko, Olenius, Tinja, Roldin, Pontus
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 30.04.2024
• Subjects: Aerosols; Air masses; Air Pollutants; Ammonia; Antarctic Regions; Cloud condensation nuclei; Cloud condensation nuclei concentrations; Cloud formation; Clustering; Coastal zone; Condensation; Condensation nuclei; Earth and Related Environmental Sciences; Energy and Climate; Geovetenskap och miljövetenskap; iodic acid; Iodine; Iodine - chemistry; Meteorologi och atmosfärforskning; Meteorological conditions; Meteorology and Atmospheric Sciences; modeling; Natural Sciences; Naturvetenskap; new particle formation; Nucleation; Oceans; Particle formation; Particle Size; Particle size distribution; Particulate Matter; secondary aerosols; Size distribution; Southern Ocean; Sulfuric acid; Thermochemistry; Antarctic Regions; Antarctica; new particle formation; secondary aerosols; iodic acid; modeling; Southern Ocean; New particle formation; Iodic acid; Modeling
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/acs.est.3c09103

New particle formation via the ion-mediated sulfuric acid and ammonia molecular clustering mechanism remains the most widely observed and experimentally verified pathway. Recent laboratory and molecular level observations indicate iodine-driven nucleation as a potentially important source of new particles, especially in coastal areas. In this study, we assess the role of iodine species in particle formation using the best available molecular thermochemistry data and coupled to a detailed 1-d column model which is run along air mass trajectories over the Southern Ocean and the coast of Antarctica. In the air masses traversing the open ocean, ion-mediated SA-NH3 clustering appears insufficient to explain the observed particle size distribution, wherein the simulated Aitken mode is lacking. Including the iodine-assisted particle formation improves the modeled Aitken mode representation with an increase in the number of freshly formed particles. This implies that more particles survive and grow to Aitken mode sizes via condensation of gaseous precursors and heterogeneous reactions. Under certain meteorological conditions, iodine-assisted particle formation can increase cloud condensation nuclei concentrations by 20%–100%.