The M1 rating indicates that building materials meet the most stringent emissions classifications for indoor air quality.
Leadership in Energy and Environmental Design is an American certification programme for green properties that aims to reduce the environmental impact of construction and building use.
The mark indicates that a product has been approved for use in Nordic Swan Ecolabelled buildings. Such products are listed in the Nordic Ecolabel Building Materials Database. In the case of detached houses, apartment buildings and daycare centres, the requirements cover the construction phase, materials and energy consumption. The Nordic Swan Ecolabel’s requirements also apply to the energy efficiency of buildings, good indoor air and the building materials used in a building.