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<p>Biogenic volatile organic compounds (BVOCs) emitted by plants represent the largest source of non-methane hydrocarbon emissions on Earth. Photochemical oxidation of BVOCs represents a significant pathway in the production of secondary organic aerosol (SOA), affecting Earth's radiative balance. Organic nitrates (RONO<span class="inline-formula">₂</span>), formed from the oxidation of BVOCs in the presence of NO<span class="inline-formula">_<i>x</i></span>, represent important aerosol precursors and affect the oxidative capacity of the atmosphere, in part by sequestering NO<span class="inline-formula">_<i>x</i></span>. In the aerosol phase, RONO<span class="inline-formula">₂</span> hydrolyze to form nitric acid and numerous water-soluble products, thus contributing to an increase in aerosol mass. However, only a small number of studies have investigated the production of RONO<span class="inline-formula">₂</span> from OH oxidation of terpenes, and among those, few have studied their hydrolysis. Here, we report a laboratory study of OH-initiated oxidation of <span class="inline-formula"><i>β</i></span>-ocimene, an acyclic, tri-olefinic monoterpene released during the daytime from vegetation, including forests, agricultural landscapes, and grasslands. We conducted studies of the OH oxidation of <span class="inline-formula"><i>β</i></span>-ocimene in the presence of NO<span class="inline-formula">_<i>x</i></span> using a 5.5 m<span class="inline-formula">³</span> all-Teflon photochemical reaction chamber, during which we quantified the total (gas- and particle-phase) RONO<span class="inline-formula">₂</span> yield and the SOA yields. We sampled the organic nitrates produced and measured their hydrolysis rate constants across a range of atmospherically relevant pH. The total organic nitrate yield was determined to be 38(<span class="inline-formula">±</span>9) %, consistent with the available literature regarding the dependence of organic nitrate production (from RO<span class="inline-formula">₂</span> <span class="inline-formula">+</span> NO) on carbon number. We found the hydrolysis rate constants to be highly pH dependent, with a hydrolysis lifetime of 51(<span class="inline-formula">±</span>13) min at pH <span class="inline-formula">=</span> 4 and 24(<span class="inline-formula">±</span>3) min at pH <span class="inline-formula">=</span> 2.5, a typical pH for deliquesced aerosols. We also employed high-resolution mass spectrometry for preliminary product identification. The results indicate that the ocimene SOA yield (<span class="inline-formula">&lt;</span> 1 %) under relevant aerosol mass loadings in the atmosphere is significantly lower than reported yields from cyclic terpenes, such as <span class="inline-formula"><i>α</i></span>-pinene, likely due to alkoxy radical decomposition and formation of smaller, higher-volatility products. This is also consistent with the observed lower particle-phase organic nitrate yields of <span class="inline-formula"><i>β</i></span>-ocimene – i.e., 1.5(<span class="inline-formula">±</span>0.5) % – under dry conditions. We observed the expected hydroxy nitrates by chemical ionization mass spectrometry (CIMS) and some secondary production of the dihydroxy dinitrates, likely produced by oxidation of the first-generation hydroxy nitrates. Lower RONO<span class="inline-formula">₂</span> yields were observed under high relative humidity (RH) conditions, indicating the importance of aerosol-phase RONO<span class="inline-formula">₂</span> hydrolysis under ambient RH. This study provides insight into the formation and fate of organic nitrates, <span class="inline-formula"><i>β</i></span>-ocimene SOA yields, and NO<span class="inline-formula">_<i>x</i></span> cycling in forested environments from daytime monoterpenes not currently included in atmospheric models.</p>