Tracers for Biogenic Secondary Organic Aerosol from α-Pinene and Related Monoterpenes: An Overview

In this review, we first address the terpenoid composition of ambient fine rural aerosol to give a report on the current state of knowledge in regard to the molecular characterisation of biogenic secondary organic aerosol tracers. The major known, recently elucidated, and still unknown tracers, which can be detected at a significant relative abundance, are listed and briefly discussed. In a second part, we provide a historic account on the discovery of 3-methyl-1,2,3-butanetricarboxylic acid, which involved a long search with several failures and a final success, and propose a revised formation pathway. Finally, we present some brief conclusions and perspectives.