Prototype Standard and Index for Environmental Noise Quality

Abstract

A prototype technical standard for environmental noise is proposed in terms enabling an index of noise quality to be defined and calculated. The standard takes into account the damaging aspects of chronic exposure to loud noise as well as psychologically disturbing aspects of typical community noises which are not loud enough to be physically dangerous. Inasmuch as the standard is intended to portray environmental quality rather than to reflect damage risk criteria, it is generally conservative with respect to work-related noise standards such as those specified by the Walsh-Healey Act. The basic standard specifies a distribution of noise intensities to which an individual might be exposed in a 24-h period. The distribution may be approximated by the composite of three Gaussian distributions with means and standard deviations of (30 and 3), (50 and 8.5), and (70 and 14) dB (A). These component distributions correspond to 8-h periods for sleep, miscellaneous daily activities, and work, respectively. Alternative strategies for obtaining data for calculating the related noise quality indices are discussed. [The work was sponsored by the Council on Environmental Quality as part of a larger study on monitoring the environment of the nation.]