Particle Formation and Growth in New Chemical Regimes

Abstract:  Understanding the mechanisms through which aerosol particles form and grow is critical for constraining a planet’s energy budget, however, our knowledge of the key processes governing particle formation and growth in diverse environments remains weak. In the coming decades, our knowledge of particle formation and growth will continue to be challenged as changing climate and anthropogenic emissions alter the chemical regimes of modern-day atmospheric chemistry on Earth and measurements from, for instance, the James Webb Space Telescope and NASA’s Dragonfly mission offer increasingly chemically resolved insights into planetary atmospheres much different from our own.
In this talk I will highlight three of our projects on particle formation and growth in new and/or understudied chemical regimes. In the first part I will discuss our field measurements in an agricultural region, focusing on reactive nitrogen and carbon species that contribute to particle formation and growth. I will briefly touch on how vertical gradients in atmospheric composition and physical properties (e.g., temperature) affect particle formation and growth. Next, I will discuss our laboratory investigations of the atmospheric chemistry of volatile methyl siloxanes. These solely anthropogenic compounds have recently come under scrutiny for their potential toxicity and environmental persistence. Moreover, field measurements suggest that they are present in urban nanoparticles. Our work investigating the kinetics, mechanism, and aerosol yield of volatile methyl siloxane oxidation addresses key gaps in our understanding of their environmental chemistry. Lastly, I will describe our laboratory experiments exploring aerosol formation in anoxic planetary atmospheres. I will primarily focus on how organosulfur formation affects aerosol mass, composition, and optical properties in Archean Eon analog experiments and will discuss the implications for habitability and the understanding of the evolution of Earth’s atmosphere.

Particle Formation and Growth in New Chemical Regimes

Abstract:  Understanding the mechanisms through which aerosol particles form and grow is critical for constraining a planet’s energy budget, however, our knowledge of the key processes governing particle formation and growth in diverse environments remains weak. In the coming decades, our knowledge of particle formation and growth will continue to be challenged as changing climate and anthropogenic emissions alter the chemical regimes of modern-day atmospheric chemistry on Earth and measurements from, for instance, the James Webb Space Telescope and NASA’s Dragonfly mission offer increasingly chemically resolved insights into planetary atmospheres much different from our own.
In this talk I will highlight three of our projects on particle formation and growth in new and/or understudied chemical regimes. In the first part I will discuss our field measurements in an agricultural region, focusing on reactive nitrogen and carbon species that contribute to particle formation and growth. I will briefly touch on how vertical gradients in atmospheric composition and physical properties (e.g., temperature) affect particle formation and growth. Next, I will discuss our laboratory investigations of the atmospheric chemistry of volatile methyl siloxanes. These solely anthropogenic compounds have recently come under scrutiny for their potential toxicity and environmental persistence. Moreover, field measurements suggest that they are present in urban nanoparticles. Our work investigating the kinetics, mechanism, and aerosol yield of volatile methyl siloxane oxidation addresses key gaps in our understanding of their environmental chemistry. Lastly, I will describe our laboratory experiments exploring aerosol formation in anoxic planetary atmospheres. I will primarily focus on how organosulfur formation affects aerosol mass, composition, and optical properties in Archean Eon analog experiments and will discuss the implications for habitability and the understanding of the evolution of Earth’s atmosphere.