Spatial Distribution Characteristics of Low-Frequency Noise in an Area Surrounding a Thermal Power Plant

Background: There is no evaluation or management of environmental low-frequency noise and there are few studies on it, particularly in the area surrounding thermal power plants.Objectives: This study aimed to conduct continuous measurement of low-frequency noise for 24 hours and cross-measurement from the thermal power plant site boundary line in order to understand the spatial distribution characteristics of low-frequency noise and evaluate it based on the low-frequency noise sound pressure level. Methods:The low-frequency noise measurement was checked for excess in each frequency band by time at four sites over three consecutive times for 24 hours.Cross-measurements were made for 30 minutes at each of five sites by separation distance from the site boundary line of the thermal power plant.The measurement method was traced to the frequency exceeding nine octave bands (12.5 Hz to 80 Hz) according to the "Low Frequency Noise Guidelines" proposed by the Ministry of Environment.The Z characteristic (dB(Z)) was applied as well.Results: As a result of the 24-hour continuous measurement, the sound pressure level for each frequency tended to decrease as the separation distance increased.As a result of cross-measurement, in the case of 80 Hz and 63 Hz, all five points exceeded the sound pressure level standard of the Ministry of Environment.In the case of 56 Hz and 40 Hz, the sound pressure level standard was exceeded at the thermal power plant boundary line and thermal power plant boundary line separation distance of 310 m. Conclusions:In the area surrounding a low-frequency noise source, four frequencies (80 Hz, 63 Hz, 50 Hz, and 40 Hz) were found to have affected the residential area adjacent to the power plant.This study suggests a need for continuous monitoring of residential areas near thermal power plants for low-frequency noise and the establishment of environmental guidelines.