(113) Thus, sulfuric acid is unlikely to be the charge carrier despite its higher gas-phase basicity. CIVP has been applied to determine the MES of a wide range of atmospheric particles and also in elucidating atmospheric reaction mechanisms. The formation of photoactive nitrosyl halides (XNO 2 ) from N 2 O 5 on sea-spray aerosol surfaces, studied by CIVP, was found to include halide insertion into N 2 O 5 leading to XNO 2 or HNO 2 .(114)