In this title the following words have the meanings indicated. “Environmental noise standard” means a goal for the limitation of noise, from all sources, that exists in a defined area under specified conditions. “Noise” means the intensity, frequency, duration, and character of sound. “Noise” includes sound and vibration of subaudible frequencies. “Political subdivision” means a county or municipal corporation of this State. “Sound level limit” means the maximum allowable noise emission from a noise source in a defined area under specified conditions. “Source” means any person or property from which sound originates.