Exploring the Molecular Properties of Atmospheric Freshly Nucleated Particles

Introduction

Aerosol particles are ubiquitous constituents in the ambient atmosphere. Ultrafine particles (< 10 nm) show adverse effects on our public health, as inhalation leads to an elevated risk of lung and cardiovascular diseases.

Climate Influence

Aerosol particles also influence the global climate by scattering sunlight away from Earth's surface and acting as seeds for cloud droplet formation. Combined, these effects lead to an overall cooling of the Earth, directly counteracting the warming effect of greenhouse gases.

Uncertainty in Climate Forecast

According to the IPCC, aerosol particles pose the largest uncertainty in global climate forecasts. This uncertainty is caused by the lack of understanding of the early growth behavior of small (< 3 nm) particles.

Sources of Aerosol Particles

The largest source of aerosol particles (50-90%) is from nucleation of vapors in the air, leading to a burst of freshly nucleated particles (FNPs) of 1-2 nm in size. However, even the basic fundamental properties of these FNPs remain unknown and cannot be studied using currently available experimental techniques.

Proposed Approach

I propose a unique approach to target the properties of FNPs by applying a versatile suite of computational methods, ranging from quantum chemical calculations to the application of conceptually new machine learning models.

Scientific Objectives

The scientific objectives are:

1. To determine the chemical composition and stability of FNPs.
2. To understand how FNPs evolve over time via exchange of vapors with the environment.
3. To investigate how FNPs transform as a consequence of chemical reactions occurring at the surface or inside the particles.

Expected Outcomes

The research will provide unprecedented insight into the molecular level properties of FNPs. This project will directly supply input parameters (chemical composition, thermodynamics, and kinetics) for atmospheric models, which are crucial in order to constrain the large uncertainty in climate predictions caused by small aerosol particles.