Equivalent effective stratospheric chlorine Equivalent effective stratospheric chlorine Equivalent effective stratospheric chlorine (EESC) provides an estimate of the total effective amount of halogens (chlorine and bromine) in the stratosphere. It is calculated from emission of chlorofluorocarbon and related halogenated compounds into the troposphere (lower atmosphere) and their efficiency in contributing to stratospheric ozone depletion (ozone depletion potential, ODP), and by making assumptions on transport times into the upper atmosphere (stratosphere). This parameter is used to quantify man-made ozone depletion and its changes with time. As a consequence of the Montreal Protocol and its amendments phasing out ozone-depleting substances (ODS), the EESC reached maximum in
Bromine weaker reducing agent than iodide, but a stronger one than chloride. These similarities led to chlorine, bromine, and iodine together being classified as one of the original triads of Johann Wolfgang Döbereiner, whose work foreshadowed the periodic law for chemical elements. It is intermediate in atomic radius between chlorine and iodine, and this leads to many of its atomic properties being similarly intermediate in value between chlorine and iodine, such as first ionisation energy, electron affinity, enthalpy of dissociation of the X molecule (X = Cl, Br, I), ionic radius, and X–X bond length. The volatility of bromine accentuates its