Figure 4.

Ambient noise is increased due to human activity. The lines represent 24-h noise measurements taken from a rodent-holding room and are depicted as time-weighted, energy-equivalent noise levels (L_eq). Statistical distribution descriptors were used, L₁, L₁₀, and L₉₀, where the numerical subscript represents the measurement duration in minutes. L_max and L_min depict noise of the highest and the lowest intensities recorded during the measurement time period. Noise is increased during normal working hours, primarily because of human activity.