Aerosol‐Mediated Partitioning of Stratospheric Cl y and NO y at Temperatures Above 200 K

Rates of aerosol‐mediated reactions involving inorganic halogen species are small but non‐negligible for moderate aerosol abundances at temperatures of 200–210 K. We have used a photochemical model to demonstrate that at these temperatures such reactions provide a significant sink for HCl. Gas‐phase production rates are slower for HCl than for ClNO 3 . The net result is preferential partitioning of Cl y into [ClNO 3 ] to compensate for the accelerated loss of [HCl]. Under such conditions, [HNO 3 ] decreases in response to enhanced partitioning of NO y into [ClNO 3 ]. The results indicate a high sensitivity and synergistic response of HCl, ClNO 3 , and HNO 3 distributions to aerosol content and temperature.