Abstract: It has been shown though numerous field studies, laboratory measurements, and the occasional modeling study that NO3 radical oxidation of monoterpenes is a significant, though often overlooked, source of secondary organic aerosol (SOA). However, this generalization is complicated by the fact that while most abundantly emitted monoterpenes (e.g. β-pinene, ∆-carene, and limonene) have moderate-to-high SOA yields with NO3 radical, the most abundantly emitted monoterpene (α-pinene) has a negligible SOA yield with NO3.