§ Mr. Oakesasked the Secretary of State for the Environment what noise and number index figure he considers to be environmentally acceptable in an urban area.
§ Mr. Graham PageThe noise and number index is a unit of measurement only. The level of aircraft noise which is environmentally acceptable varies according to location and types of building. The Department of the Environment Circular "Planning and Noise" sets out criteria for assessing levels of acceptability for new development.