Fig. 4. Simulated dependence of the concentration ratio C_PROD/C_ISOP on NO_y concentration ${\mathit{C}}_{\mathrm{N}{\mathrm{O}}_{\mathit{y}}}$.

Results are shown for two different values of C_OH,noon, as well as the full model compared to a model that omitted isoprene ozonolysis. At fixed C_OH,noon, ${\mathit{C}}_{\mathrm{N}{\mathrm{O}}_{\mathit{y}}}$ affects C_PROD/C_ISOP via the effects on ${\mathit{y}}_{\mathit{i}}^{*}({\mathit{C}}_{\mathrm{N}{\mathrm{O}}_{\mathit{y}}})$ and ${\mathit{C}}_{{\mathrm{O}}_3}$(C_NOy) (Eq. 5). Solid lines show results for the full model of Eq. 5, and dashed lines show results for a model that omits isoprene ozonolysis (that is, ${\mathit{C}}_{{\mathrm{O}}_3}$ = 0). For all cases, t = 8.5 hours, corresponding to 14:30 (local time).