Table 2.

WHO recommended limits for noise exposure levels and national legal thresholds for average noise exposure (https://www.euro.who.int/__data/assets/pdf_file/0009/383922/noise-guidelines-exec-sum-eng.pdf).^*

Noise source	Lden	Lnight	Quality of evidence	EU / US threshold
Road noise	< 53 dB	< 45 dB	strong	No legally binding limits for ambient noise. Legal limits for LREL,8h of 85–90 dB (US) and LEX of 80–85 dB (EU) for occupational noise sources; peak (impulse) noise limits 135–140 dB.
Railway noise	< 54 dB	< 44 dB	strong
Aircraft noise	< 45 dB	< 40 dB	strong
Wind turbines	< 45 dB	-	limited
Leisure ambient noise	< 70 dB (LAeq,24h)	-	limited

^*dB, decibel; Lden, average sound pressure level over 24h adjusted for day-evening-night with a penalty of 5 dB for the evening time (7–11pm or 6–10pm) and a penalty of 10 dB for the night time (11pm-7am or 10pm-6am); Lnight, average sound pressure level for night time (11pm-7am or 10pm-6am); LAeq, average sound pressure level over 24h (A-weighted means adjusted for the human acoustic range). The recommended limits are related to the most seriously exposed face of the building. Strong quality of evidence requires fast action of policy makers, whereas limited quality of evidence requires substantial discussions among the decision makers, also considering the opinion of scientists, clinicians, and health care system representatives. LREL,8h, recommended exposure level over 8h at workplace by the US CDC-associated National Institute for Occupational Safety and Health (NIOSH). LEX, recommended exposure level over 24h or 7d at workplace by the European agency for occupational safety and health (EU-OSHA)