where LH-C,Aeq,T is the energy mean of diffuse-field-related A-weighted equivalent-continuous SPLs under headset, in dBA; LB-N,Aeq,T is the energy mean of A-weighted equivalent-continuous SPLs of background noise, in dBA; TH is the declared time of the headset usage per working day, in hours; TB-N is the effective duration of nonheadset work activities, in hours; To is the reference duration, To = 8 h.Similar calculation was made for the nonequipped ear. However, in this case, instead of diffuse-field-related A-weighted equivalent-continuous SPL under headset, the noise level measured outside the aforesaid ear was taken into consideration.