COMPUTER-ASSISTED EXPERIMENTAL STUDY OF THE HYDROCARBON OXIDATION REACTION MECHANISMS IN A CONDENSED PHASE: REDOX IN POLYCYCLIC AROMATIC HYDROCARBONS IN THE ATMOSPHERE.

Polycyclic aromatic hydrocarbons (PAHs) are those incomplete products of combustion that are the persistent organic pollutants contributing substantially to the atmospheric redox chemistry. In spite of well understood implications in the human health, climatic forcing, and second aerosol formation, their oxidation behaviour in condensed media is poorly understood. This paper employs a computerised technique of modelling the hydrocarbon oxidation mechanisms of analytical PAHs in condensed-phase atmospheric conditions. The conjunction of quantum chemical and molecular dynamics simulations makes the study be able to define the most significant redox transformations, radical intermediates, and pathways of the products, which influence the degradation of PAH. The findings also show that addition of hydroxyl radicals and electron transfers are the most common contributors to the PAH oxidation in aqueous-organic microenvironment that leads to the formation of oxygenated derivatives of PAH, which can significantly enhance hygroscopicity and toxicity of the particles. Results indicate that computational modelling will be able to give predictive data regarding the kinetics and thermodynamic viability of PAH transformations, which will also match with the recent experimental results. The paper will fill the gap between the molecular-level processes and the atmospheric-level processes to give new insights into environmental risks assessment and policy-making. It is a work that defines a methodological basis of assessment of condensed-phase hydrocarbon oxidation and it highlights the importance of the use of computational chemistry in the study of atmospheric oxidation. [ABSTRACT FROM AUTHOR]