Variation of the outdoor noise level and the sound attenuation of windows with elevation above the ground

In an attempt to cope with the problem of providing suitably quiet dwellings in noisy urban environments, it has sometimes been suggested that the lower floors of high-rise buildings might be used for offices (or other noise-insensitive uses), while the upper, presumably quieter, floors could be used for housing. This paper suggests that the proposal is not practical since, in many urban areas, the upper floors of buildings are exposed to almost as much noise as the floors near street level.