Co-Oxidation

CO oxidation chemistry diagnostics from Seinfeld & Pandis (2006) Ch. 6 §6.3 Eqs. 6.9-6.18, pp. 212-219. CO oxidation is the simplest hydrocarbon-oxidation mechanism and illustrates the catalytic HOx cycling that drives tropospheric ozone production (net: CO + 2O₂ + hν → CO₂ + O₃, with OH regenerated through HO₂ + NO). This observed-only algebraic component implements six diagnostic relations: the OH loss rate L_OH (to CO, NO₂, O₃), the HO₂ loss rate L_HO2 (to NO, the HO₂ self-reaction, and O₃), the HOx radical-termination loss rate L_HOx (OH+NO₂→HNO₃ plus the HO₂ self-reaction), the high-NOx HO₂ steady-state concentration HO2_ss (Eq. 6.18), the net ozone production rate P_O3 (HO₂+NO production minus the OH+O₃ and HO₂+O₃ loss channels), and the HOx chain length (propagation rate over termination rate — the number of OH-HO₂ cycles before radical termination). Observed-only algebraic system (no time derivatives): twelve variables (six inputs CO/OH/HO₂/NO/NO₂/O₃ encoded as parameters, six outputs L_OH/L_HO2/L_HOx/HO2_ss/P_O3/chain_length as state), six rate-constant parameters (k_CO_OH, k_HO2_NO, k_HO2_HO2, k_OH_NO2, k_HO2_O3, k_OH_O3), one dimensionless stoichiometric constant (two), and six algebraic equations. Migrated from GasChem.jl@8c12c048 src/co_oxidation.jl:88 (`COOxidation` @component).

Ozone Production Efficiency (OPE) diagnostic from Seinfeld & Pandis (2006) Ch. 6 §6.3 Eqs. 6.21-6.24, pp. 212-219. OPE = Δ[O₃]/Δ[NOx] is the number of ozone molecules produced per molecule of NOx consumed — a central diagnostic for the NOx-VOC-O₃ regime structure of tropospheric photochemistry. This observed-only algebraic component implements three relations: gross ozone production rate P_O3 = k_HO2_NO·[HO₂]·[NO] + k_RO2_NO·[RO₂]·[NO] (the two peroxy-radical + NO channels — each peroxy+NO reaction makes an NO₂ whose photolysis yields an O₃), NOx loss rate L_NOx = k_OH_NO2·[OH]·[NO₂] (the OH + NO₂ + M → HNO₃ termination, the dominant daytime NOx sink), and OPE = P_O3 / L_NOx. High OPE (low-NOx, NOx-limited regime) means each NOx molecule cycles through many O₃-producing reactions before it is lost as nitric acid; low OPE (high-NOx, VOC-limited regime) means NOx is removed before it can drive much O₃ production. Observed-only algebraic system (no time derivatives): eight variables (five inputs OH/HO₂/RO₂/NO/NO₂ encoded as parameters, three outputs P_O3/L_NOx/OPE as state) plus three rate-constant parameters (k_HO2_NO, k_RO2_NO, k_OH_NO2) and three algebraic equations. Migrated from GasChem.jl@280ee50f src/co_oxidation.jl:183 (`OzoneProductionEfficiency` @component).