Noise Glossary dB: The Decibel (dB) is the unit used to measure the magnitude or intensity of sound. The decibel uses a logarithmic scale to cover the very large range of sound pressures that can be heard by the human ear. Under the decibel unit of measure, a 10 dB increase will be perceived by most people to be a doubling in loudness, i.e., 80 dB seems twice as loud as 70 dB.
dBA: The A-weighted Decibel (dBA) is the most common unit used for measuring
environmental sound levels. It adjusts, or weights, the frequency components of sound to conform with the normal response of the human ear at conversational levels. dBA is an international metric that is used for assessing environmental noise exposure of all noise sources.
DNL: The Day-night Average Sound Level (DNL) is the level of noise expressed (in decibels) as a 24-hour average. Nighttime noise, between the hours of 10:00 pm. and 7:00 a.m. is weighted; that is, given an additional 10 decibels to compensate for sleep interference and other disruptions caused by nighttime noise. An annual average of DNLs is used by the Federal Aviation Administration to describe airport noise exposure.
Areas with noise impacts less than 65 dB DNL are considered "compatible" with residential use; areas at or above 65 dB DNL are designated "incompatible" with residential use. 
If American Standards are used in Singapore
Punggol should be classified as " INCOMPATIBLE FOR RESIDENTIAL USED ".
