Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change

Abstract

In spite of impressive advances in recent years, our present understanding of or-ganic aerosol (OA) composition, physical and chemical properties, sources and trans-formation characteristics is still rather limited, and their environmental effects remainhighly uncertain. Therefore, the three atmosphere-related projects of the International Geosphere Biosphere Programme (IGBP) – IGAC (International Global AtmosphericChemistry Project), iLEAPS (Integrated Land Ecosystem Atmosphere Process Study)and SOLAS (Surface Ocean-Lower Atmosphere Study) – organised a workshop withthe specific goal of discussing and prioritizing issues related to organic aerosol andtheir effects on atmospheric processes and climate, providing a basis for future collaborative activities at the international level. Four main topical areas were addressed:(a) sources of OA; (b) formation and transformation of OA; (c) physical and chemicalstate of OA; (d) atmospheric modelling of OA. Key questions and research priorities re-garding these four areas have been synthesized in this paper, and outstanding issuesfor future research are presented for each topical area. In addition, an effort is made to formulate a basic set of consistent and universally applicable terms and definitionsfor coherent description of atmospheric OA across different scientific scales and disci-plines. In fact, the terminologies used in the past and present scientific literature arenot always consistent, and this may lead to misunderstandings and confusion in thecommunication between specialists from different disciplines and potentially inhibit or retard scientific progress.