Improvements of the RADM1 gas-phase chemical mechanism

The RADM1 gas-phase chemical mechanism was improved by updating rate consta nts, introducing photodissociation, incorporating the permutation reactions of organic peroxy radicals, and replacing the lumped NO3 + N2O5 reaction r ates expressions with explicit ones. Both the original RADM1 and the revise d RADM1 chemical mechanism were compared with the explicit Master Mechanism of NCAR (National Center for Atmospheric Research, USA) using the trace ga s concentrations observed at the China Regional Background Atmospheric Obse rvatory as model initial conditions. It was shown that the revised RADM1 ch emical mechanism was much better than the original in modeling atmospheric chemistry, especially on ozone, for the China region.