Loudness doesn't add — it multiplies. Every three decibels doubles the sound energy hitting your ear, which means the time you can safely take it is cut in half. That single exponent explains why a lawn mower is a chore, a concert is a countdown, and 1.5 billion people are already living with hearing they will never get back.
1.5 billion
People alive today — roughly one in five — have some degree of hearing loss. By 2050 the World Health Organization projects nearly 2.5 billion. Hearing loss is the third-largest cause of years lived with disability on Earth.
01 / The Scale
A decibel is not a unit of loudness. It's a ratio.
The decibel scale is logarithmic: 10 dB more is ten times the sound energy. So the gap between a whisper and a jet engine isn't 100 units of anything — it's a factor of ten billion. Damage begins around 85 dBA, barely past a lawn mower.
30
Whisper
60
Normal conversation
85
Lawn mower damage begins
95
Motorcycle
110
Rock concert
120
Siren
140
Fireworks at close range
Spectrum: 20–140 dBA. Red line marks the NIOSH damage threshold of 85 dBA. Sound levels from NIOSH / CDC noise guidance; values vary with distance. Above ~120 dBA, injury can be immediate rather than cumulative.
02 / The Rule
Every three decibels halves your day.
NIOSH sets its recommended exposure limit at 85 dBA for eight hours, with a 3-decibel exchange rate — because +3 dB is exactly double the energy. Plotted on a logarithmic time axis, the safe-exposure staircase falls in a perfectly straight line. Ten decibels of extra volume costs you 94% of your time.
85 dBA
8 hours
88 dBA
4 hours
91 dBA
2 hours
94 dBA
1 hour
97 dBA
30 minutes
100 dBA
15 minutes
103 dBA
7 min 30 s
106 dBA
3 min 45 s
109 dBA
1 min 52 s
112 dBA
56 seconds
115 dBA
28 seconds
Bar length is proportional to log₁₀(seconds of safe exposure). Durations derive from the NIOSH recommended exposure limit — 85 dBA for 8 hours with a 3-dB exchange rate (NIOSH Criteria for a Recommended Standard: Occupational Noise Exposure, 1998). Note: OSHA's legally enforceable limit is more permissive — 90 dBA for 8 hours on a 5-dB exchange rate.
03 / The Curve
The quiet epidemic is compounding.
The Global Burden of Disease study counted 1.57 billion people with hearing loss in 2019 and projects 2.45 billion by 2050 — a 56% rise, driven mostly by ageing and population growth rather than by noise alone. The number who need rehabilitation grows too: 430 million today, more than 700 million by mid-century.
Endpoints are measured/published estimates: 1.57B (2019) and 2.45B (2050) from GBD 2019 Hearing Loss Collaborators, The Lancet, 2021; 430M and >700M from WHO. Illustrative: the straight paths between endpoints are simple interpolations for shape, not year-by-year data.
04 / The Volunteers
A billion young people are choosing the dose.
Most industrial noise is imposed. Personal audio is not. A 2022 systematic review of 33 studies covering more than 19,000 people aged 12–34 measured how many listen at levels and durations known to be unsafe — and then scaled it to the world's 2.8 billion young people.
Young people using headphones at unsafe levels24%
Exposed to unsafe levels at clubs, concerts & venues48%
Share of 12–34-year-olds at risk worldwide (range)24–48%
0.67–1.35B
Young people worldwide potentially at risk of hearing loss from unsafe listening.
BMJ Global Health, 2022
95.1M
Children aged 5–19 already living with hearing loss.
WHO
>25%
Of people over 60 have disabling hearing loss (>35 dB in the better ear).
WHO
Dillard et al., “Prevalence and global estimates of unsafe listening practices in adolescents and young adults,” BMJ Global Health, 2022 — meta-analysis of 33 studies, n>19,000, ages 12–34.
05 / The Ambient Dose
Traffic noise is a cardiovascular problem.
Chronic noise doesn't just wear out the ear. It keeps the stress response switched on — raising blood pressure, disturbing sleep, and, over decades, killing people. The European Environment Agency's 2025 assessment is the largest audit of that effect anywhere.
110M
Europeans — more than 20% — exposed to transport noise above 55 dB (day-evening-night). Using WHO guideline levels instead, it's about 150 million.
EEA, 2025
66,000
Premature deaths a year attributed to long-term transport noise exposure.
EEA, 2025
50,000
New cardiovascular disease cases a year linked to noise.
EEA, 2025
22,000
New type 2 diabetes cases a year linked to noise.
EEA, 2025
560,000
Children a year with noise-linked reading-comprehension impairment.
EEA, 2025
€95.6B
Minimum annual economic cost in Europe — about 0.6% of regional GDP.
EEA, 2025
European Environment Agency, Environmental Noise in Europe 2025 (published 24 June 2025). Between 2017 and 2022 the number of Europeans highly annoyed by transport noise fell by only about 3% — against a target of 30% by 2030.
06 / The Bill
A trillion dollars a year, and the cheapest fix on the shelf.
Unaddressed hearing loss costs the world close to a trillion dollars annually in health care, lost productivity and educational support. The intervention is unusually cheap — and unusually unavailable.
$1T
Estimated annual global cost of unaddressed hearing loss.
WHO
$1.40
Additional investment per person per year needed to scale up ear and hearing care globally.
WHO
$16
Returned for every $1 invested, over a ten-year horizon.
WHO
<10%
Share of global hearing-aid need met by current production — and under 3% in many low-income countries.
WHO World Report on Hearing, 2021
Hearing loss is also, uniquely, preventable at the source: the damage caused by noise is entirely avoidable, and the ear gives no pain signal when it is being destroyed.
Why it matters
Hair cells do not grow back.
The ~16,000 sensory hair cells in each human cochlea are all you are issued. Noise kills them silently and permanently, and the loss is cumulative across a lifetime — every loud night is deposited in the same account. The good news is that the whole of noise-induced hearing loss, unlike the age-related kind, is optional.
60 / 60 Play personal audio at no more than 60% of maximum volume, for no more than 60 minutes at a stretch. If someone an arm's length away has to shout, it's too loud.
Carry plugs Musician's earplugs cut 15–20 dB fairly flatly across frequencies — turning a 110 dB concert into roughly a 92 dB one without muffling the music.
Measure it Free sound-level meter apps (NIOSH publishes one) are accurate enough to tell you when a room has crossed 85 dBA. Most gyms, bars and blenders do.
Get tested Hearing loss creeps in from the high frequencies down, so it is usually invisible until speech-in-noise gets hard. A baseline audiogram in your twenties is worth having.
Sources & notes
World Health Organization — “Deafness and hearing loss” fact sheet (updated March 2026): 1.5 billion with some degree of hearing loss; nearly 2.5 billion projected by 2050; 430 million requiring rehabilitation now and >700 million by 2050; 95.1 million children 5–19; >25% of over-60s with disabling loss; >1 billion young adults at risk; ~US$1 trillion annual cost; US$1.40 per person investment returning ~US$16 per dollar over 10 years.
GBD 2019 Hearing Loss Collaborators — “Hearing loss prevalence and years lived with disability, 1990–2019,” The Lancet, 2021: 1.57 billion in 2019 (≈1 in 5 people); 2.45 billion projected for 2050, a 56.1% increase.
NIOSH — Criteria for a Recommended Standard: Occupational Noise Exposure, Revised Criteria 1998: recommended exposure limit of 85 dBA as an 8-hour time-weighted average with a 3-dB exchange rate. The exposure-time staircase in section 02 is computed from that rule.
OSHA — Occupational Noise Exposure standard: permissible exposure limit of 90 dBA over 8 hours using a 5-dB exchange rate, for comparison.
NIOSH / CDC — noise-level guidance for common sounds used in the spectrum strip (whisper ≈30 dB, conversation ≈60 dB, lawn mower ≈85 dB, motorcycle ≈95 dB, concert ≈110 dB, siren ≈120 dB, fireworks at close range ≈140 dB). Levels vary with distance and source; treat as representative rather than exact.
Dillard L. K. et al. — “Prevalence and global estimates of unsafe listening practices in adolescents and young adults: a systematic review and meta-analysis,” BMJ Global Health, 2022: 24% unsafe headphone listening, 48% unsafe exposure at entertainment venues; 0.67–1.35 billion young people potentially at risk.
European Environment Agency — Environmental Noise in Europe 2025 (24 June 2025): 110 million Europeans (>20%) above 55 dB Lden and ~150 million above WHO guideline levels; 66,000 premature deaths, 50,000 cardiovascular cases, 22,000 type 2 diabetes cases and 560,000 cases of childhood reading impairment per year; ≥€95.6 billion annual cost, ~0.6% of GDP; ~3% reduction in high annoyance 2017–2022 against a 30% target for 2030.
WHO — World Report on Hearing, 2021: current hearing-aid production meets less than 10% of global need, and under 3% of need in many low-income countries.
Note on figures: all numbers above are published estimates from the named institutions. The only illustrative element in this edition is the straight-line shape between the 2019 and 2050 endpoints in the section 03 chart; the endpoints themselves are published values.