WHO Night Noise Limits
WHO gives two figures for night noise, one inside and one outside:
- Inside the bedroom: under 30 dBA during the night, for sleep of good quality.
- Outside the bedroom: an annual night average (Lnight) under 40 dB, to prevent harm to health from night noise.
The 40 dB outdoor target comes from WHO's Night Noise Guidelines for Europe (2009). Where a country can't reach it soon, WHO recommends 55 dB as an interim target. The guidelines aim to protect the most vulnerable groups, such as children, the chronically ill, and the elderly.
Lnight is an average over the night hours across a whole year, measured outside. It is a planning figure for roads and airports, so a single night in your room won't match it. The 30 dBA bedroom figure is the one to compare with your own readings.
Night Limits for Traffic, Rail, and Aircraft
WHO's Environmental Noise Guidelines for the European Region set night limits by noise source:
- Road traffic: under 45 dB Lnight
- Railways: under 44 dB Lnight
- Aircraft: under 40 dB Lnight
WHO lists sleep disturbance among the health effects of noise, along with cardiovascular effects and poorer work and school performance. It also notes that noise at night can lead to more medical visits and more spending on sleeping pills.
How to Measure Your Bedroom
- Open the neighbor noise meter. It leads with the average level (Leq), which is the number to compare with 30 dBA.
- Put the phone near your pillow, with the windows and doors as they are when you sleep.
- Measure at night, when the noise bothers you, for at least a few minutes. Note the average and the maximum.
The decibel meter shows the same readings with a level graph. For how loud everyday sounds are, see the noise levels chart.
Quiet rooms are where phone mics struggle most. A cheap mic hears its own hiss, so in a quiet bedroom the meter may show the lowest level the mic can measure. See how accurate a phone decibel meter is before you trust a reading near 30 dB.
If Your Bedroom Is Too Loud
WHO groups noise fixes from the source to the listener. First come quieter sources or limits on when they run. Then come changes to the path, such as insulating the home.
- Find the source first. A reading log with dates and times helps if it is a neighbor, a landlord issue, or a local noise rule.
- Block the path: close windows on the noisy side, and sleep in the quietest room if you can.
- Protect your own ears: our guide to earplugs for sleeping compares foam and reusable plugs, including for side sleepers.
If you still sleep badly in a quiet room, noise may not be the cause. Talk to a doctor.