Through various international agreements, Norway has committed to reducing its emissions to air of certain hazardous substances from the 1990 level. Different protocols under the Convention on Long-Range Transboundary Air Pollution (CLRTAP) set out the targets for emissions with regional effects. One of these protocols, the Aarhus Protocol, stipulates the commitments for the reduction of PAHs and dioxins, lead, cadmium and mercury. For copper, chromium and arsenic, there are no commitments, but there are requirements for reporting emissions.