Can population density be used to determine ambient noise levels

In 1974, the U.S. Environmental Protection Agency (USEPA) published a report endorsing the day–night average sound level (DNL) for nationwide use. Included in this report was an equation predicting DNL from the number of people per square mile. The equation was based on monitoring from 100 sites throughout the U.S. To determine whether the 1974 equation still provided a realistic estimate 25 years later, monitoring was conducted at 50 sites in Baltimore County, Maryland. Population density ranged from 600 to 13 000 people per square mile. To explore seasonal differences and test–retest reliability, the monitoring was conducted for 24 h in the summer and 24 h in the winter. The results are compared to those of the USEPA.