Member States shall allow the putting into service and use of radio equipment if it complies with this Directive when it is properly installed, maintained and used for its intended purpose. Without prejudice to their obligations under Decision No 676/2002/EC and to the conditions attached to authorisations for the use of frequencies in conformity with Union law, in particular under Article 9(3) and (4) of Directive 2002/21/EC, Member States may only introduce additional requirements for the putting into service and/or use of radio equipment for reasons related to the effective and efficient use of the radio spectrum, to the avoidance of harmful interference, to the avoidance of electromagnetic disturbances or to public health.