Bromine

Stratospheric bromine catalytic ozone-destruction cycle (BrOx). Three ODEs (Br, BrO, HOBr) and two algebraic family identities (BrOx = Br + BrO; Bry = Br + BrO + HOBr). Reactions: Br + O3 → BrO + O2 (Arrhenius); BrO + O → Br + O2; BrO + ClO → Br + Cl + O2 (constant rate); BrO + HO2 → HOBr + O2; HOBr + hν → OH + Br (photolysis). Unlike chlorine, bromine has no stable HBr reservoir because Br + CH4 is endothermic (Seinfeld & Pandis Page 169). Bromine is approximately 50× more effective than chlorine in destroying ozone on an atom-for-atom basis. Migrated from GasChem.jl@8c12c048 src/StratosphericChemistry.jl:390 (`BrOxCycle` @component). Rate coefficients converted CGS → SI: cm³/molec/s × 1e-6 → m³/s.