The 18-year-old went camping in a forest in Ningbo, Zhejiang province, China, in early July. By midday, the cicadas in the dense trees had reached full volume. He stayed for four hours without ear protection.
By evening, his ears felt full and swollen, and he could no longer make out high-pitched sounds. Birdsong was gone. So were the alert tones on his phone. The student, identified by the surname Yang, was diagnosed with temporary hearing impairment from noise exposure. His hearing returned to normal after medical treatment and 14 days away from noise, according to reporting by the South China Morning Post, citing local outlet Shandian News. The story drew 4.5 million views on Chinese social media.
Here is the part that makes this more than a curiosity. American federal noise scientists have already gone on record saying cicadas are not the hearing hazard the headlines suggest, and their explanation is more useful than the anecdote.
What Actually Happened Inside His Ears
Sound waves reaching the inner ear travel through fluid in the cochlea, where sensory hair cells convert vibrations into electrical signals. A loud sound mechanically over-drives those cells. According to the National Institute on Deafness and Other Communication Disorders, most noise-induced hearing loss results from damage and eventual death of these hair cells, and unlike birds and amphibians, humans do not regrow them.
The reversible version is called a temporary threshold shift. As hearing thresholds rise, high frequencies fade first, tinnitus may appear, and the ears may feel blocked or full. NIDCD notes that a temporary threshold shift usually disappears within 16 to 48 hours after exposure ends. Yang's recovery took considerably longer. NIDCD also cautions that recent research suggests residual long-term damage can remain even when hearing appears to return.
The high-frequency pattern is the clinical fingerprint. Birdsong and phone alerts sit in exactly the range that noise damage takes first, which is why people often notice consonants and chirping disappearing before they notice volume dropping.
Why Federal Scientists Pushed Back on Cicada Panic
During the 2021 Brood X emergence, journalists with sound meters reported cicada readings of 90 to 100 decibels, and headlines followed. The NIOSH Noise and Bio-Acoustics Team published a rebuttal that directly addressed the misinformation, including a widely circulated claim attributed to the CDC that 15 minutes of cicada buzzing at 100 decibels was enough to cause hearing loss. NIOSH listed that statement among the false ones.
Their correction rests on the exchange rate. As explained in the NIOSH science bulletin, safe exposure time is halved with each 3-decibel increase: 8 hours at 85 dBA, 4 hours at 88, 2 hours at 91, 1 hour at 94, 30 minutes at 97, and 15 minutes at 100. Those limits, set out in the agency's recommended standard, assume repeated exposure across 8-hour workdays, 40-hour weeks, and a 40-year working lifetime. NIOSH wrote that exposure at 85 dBA and higher is "not necessarily immediately hazardous to hearing."
Distance matters just as much. Sound level drops roughly 6 decibels with each doubling of distance from the source. NIOSH gives the following worked example: cicada noise measured 3 feet from a heavily infested tree may approach 100 dBA, but falls to about 94 dBA at 6 feet, 88 dBA at 12 feet, and 82 dBA at 24 feet. Standing under the tree and standing across the clearing are entirely different exposures.
A single loud exposure, even one exceeding the safe duration, will not necessarily damage hearing. Most noise-induced hearing loss comes from repeated exposure over time.
Why This Case Still Happened
None of that makes Yang's injury implausible. He was inside a dense forest, meaning close to many simultaneous sources, for four continuous hours with nothing between the sound and his ears. Chinese specialists have put a single cicada at roughly 70 decibels at close range, harmless on its own, while a full chorus at the peak of summer heat climbs well past 80.
NIOSH is also explicit that susceptibility varies between individuals, and that there is no way to know whether someone is highly vulnerable until after the damage is done. That is precisely why the agency recommends protective action whenever noise exceeds 85 dBA regardless of duration: not because the sound is instantly dangerous, but because nobody knows how long it will last, what else will accumulate that day, or how their own cochlea will respond.
The Environmental Protection Agency set a separate 70 dBA limit intended to prevent hearing loss across 24-hour exposure over a 70-year lifetime, a reminder that environmental and occupational thresholds answer different questions.
This story carries real limits. It is a single case reported through local media rather than a peer-reviewed case report, with no published audiogram, no measured decibel level at his location, and no independent verification of the clinical details. China Daily has reported similar accounts involving a gardener and a resident of a heavily wooded apartment complex, also via local news. One anecdote cannot establish how often this occurs or who is at risk.
The transferable lesson is not about insects. Move away from sustained loud sound, put distance between yourself and the source, and treat ear fullness, muffled hearing or new ringing as a signal to leave and, if symptoms persist, to see a clinician. Temporary threshold shifts often recover. Repeated ones can stop recovering.
Key Questions Answered
What happened to the teenager?
An 18-year-old in Ningbo, China, spent four hours in a cicada-filled forest without ear protection, developed ear fullness and loss of high-frequency hearing, and recovered after 14 days with medical treatment and noise avoidance.
Are cicadas actually dangerous to hearing?
NIOSH has publicly debunked claims that cicada noise routinely causes hearing damage, noting that risk depends on duration, repetition, and distance from the source, not on peak decibel readings alone.
What is a temporary threshold shift?
A reversible rise in hearing thresholds after noise exposure. NIDCD states it usually disappears within 16 to 48 hours once exposure stops, though some residual damage may remain.
Why do high-pitched sounds disappear first?
Noise damage typically affects high-frequency hearing earliest, which is why birdsong and phone alerts fade before overall volume seems to drop.
How does distance change the risk?
Sound level falls by roughly 6 decibels each time the distance from the source doubles, so moving away substantially reduces exposure.
When is noise-related hearing loss permanent?
When hair cells die rather than merely being stressed. Human hair cells do not regenerate, and repeated temporary shifts can progress to permanent loss.
What should someone do after a loud exposure?
Leave the noisy environment, limit further loud sound, and seek medical evaluation if ear fullness, muffled hearing, or ringing persists rather than resolving within a day or two.
