Isoprene Forms Secondary Organic Aerosol through Cloud Processing:Model Simulations

摘要

Isoprene accounts for more than half of non-methane volatile organics globally.Despite extensive experimentation,homogeneous formation of secondary organic aerosol (SOA) from isoprene remains unproven.Herein,an in-cloud process is identified in which isoprene produces SOA.Interstitial oxidation of isoprene produces water-soluble aldehydes that react in cloud droplets to form organic acids.Upon cloud evaporation new organic particulate matter is formed.Cloud processing of isoprene contributes at least 1.6 Tg yr~(-1) to a global biogenic SOA production of 8-40 Tg yr~(-1).We conclude that cloud processing of isoprene is an important contributor to SOA production,altering the global distribution of hygroscopic organic aerosol and cloud condensation nuclei.