3. Stratospheric ozone depletors

Evidence suggests that stratospheric ozone depletion is being caused by anthropogenic emissions of chlorine and bromine-containing substances (halocarbons) such as CFCs and halons, and HCFCs, which are similar to CFCs but have a lower potential for depleting ozone and in some cases are being used as transitional replacements. Emissions of methyl chloroform, carbon tetrachloride and methyl bromide also contribute to the effect.

International agreement to limit the production and consumption of ozone depleting substances and phase out use of these substances was reached in 1987 through the Montreal Protocol on Substances that Deplete the Ozone Layer, and have subsequently been strengthened by a number of Amendments. In addition, the EU introduced EC Regulation 3093/94 which in some cases adopted a faster timescale for the reductions. Overall this has led to substantial reductions in the production and consumption of these substances over the last 10 years.

The NAEI does not contain inventories for the emissions of these substances although they are included within the emissions for non-methane volatile organic compounds. In addition, the NAEI does now contain separate inventories for hydrofluorocarbons and perfluorocarbons which are being used as substitutes for CFCs and HCFCs in many domestic, commercial and industrial applications. Both are greenhouse gases and are discussed in detail in Chapter 3.