Role of nitrogen oxides in the stratosphere: A reevaluation based on laboratory studies

The changes in chemical partitioning and stratospheric O 3 abundance due to the recently measured rate coefficients for the O + NO 2 , OH + HNO 3 , and OH + NO 2 reactions are examined using a two‐dimensional model. The rate constant changes increase NO x abundance (up to 40%) and NO x ‐catalyzed O 3 destruction, and extend down by several kilometers the altitude region where NO x dominates catalytic O 3 destruction. Reductions in the abundance of HO x (10–30%) and ClO x (20‐40–) in the lower stratosphere partially buffer the effect on column O 3 amount. Column O 3 at middle and high latitudes is reduced by 2–10% depending on season for current halogen levels. The model derived long‐term O 3 trend at midlatitudes due to increases in anthropogenic halogens is reduced by approximately 30%.