Some commonly used acoustical terms have been employed throughout this report. The following definitions are intended to provide the readers with a general appreciation of the meaning of the more frequently used technical terms.

A-Weighting Decibel, dB(A) - An A-weighted noise level has been filtered in such a way as to represent the way in which the human ear perceives sound. This weighting reflects the fact that the human ear is not as sensitive to lower frequencies as it is to higher frequencies.

Percentile Noise Level, L90 - It is a noise level which is exceeded for 90 per cent of the measurement period.

Equivalent Noise Level, Leq 30min - It is an equivalent continuous sound pressure level measured over 30 minutes. It is defined as the constant sound pressure level, which would result in the same amount of sound energy as that due to the actual noise, if operated over the same measurement period.

Acceptable Noise Level, ANL - The appropriate ANL, as promulgated under the relevant Technical Memorandum of the Noise Control Ordinance, for a particular Noise Sensitive Receiver (NSR) is dependent upon the character of the area within which the NSR is located, and the time of day under consideration.