Community noise equivalent level
The community noise equivalent level (CNEL) is also used to characterize average sound levels over a 24-hour period, with weighting factors included for evening and nighttime sound levels. Leq values for the evening period (7:00 p.m.–10:00 p.m.) are increased by 5 dB, while Leq values for the nighttime period (10:00 p.m.–7:00 a.m.) are increased by 10 dB. For given set of sound measurements, the CNEL value will usually be about 1 dB higher than the Ldn value. In practice, CNEL and Ldn are often used interchangeably.