EXpected secondary Aerosol ContenT - Molecular Level Secondary Aerosol Formation | EXACT | Proyecto | Ficha informativa | HORIZON | CORDIS

Objetivo

Secondary aerosols (SecA) are crucial components of the Earth-Atmosphere system. They dominate the submicron airborne
particulate matter distribution, are crucial components of air pollution and the main origin of clouds, and thus, climate. SecA forms by
gas-to-particle conversion and condensation of very low volatile compounds sourced by oxidation of gas-phase constituents.
Recently we showed in a paradigm shift observation how direct aerosol sources form extremely rapidly after only a single reaction
with an oxidant molecule, in stark contrast to previous view of long processing timescales necessitated by the requirement of several
consecutive reactions with scarce oxidant compounds.

Aerosol processes persistently remain as the largest uncertainty in climate predictions. Especially the early meters of particulate
matter evolution, the formation and survival of fresh molecular cluster and tiny particles at the critical one to few nanometres scale,
keeps eluding researchers. Most of these particle pre-stages either evaporate or get scavenged by larger droplets and surfaces. To
survive, the tiny particle embryos must grow fast enough to overcome the repulsing forces acting against, and eventually form a new
aerosol particle. Only the lowest volatile vapours can grow the smallest of these nano seeds. Strangely, we have recently shown how
the lowest volatile vapours form extremely rapidly and pose the question if they are the reason SecA can form in the ambient air.

In EXACT we use a combined state-of-the-science experimental-computational-modelling approach to resolve how the very-low
volatile chemicals form extremely rapidly and contribute to nano seed particle growth at the crucial 2 to 10 nanometres range. The
project utilizes multi-ion, multi pressure chemical ionization combined with detail quantum chemical computations, automated
reaction discovery methods and molecular level SecA modelling to resolve the importance of this newly found fast chemistry.