No quiet at home:
The reality of living with Singapore’s traffic noise

In one of the world’s densest cities, peace and quiet are hard to find. As a global hub, Singapore’s skies are always busy, while an extensive web of roads and a well-connected MRT network keep residents constantly on the move. But these conveniences come at a noisy price – the traffic never stops, and for those living nearby, the constant sound is often impossible to escape.

“Singapore’s land scarcity forces housing, schools and workplaces to be built immediately adjacent to expressways, arterial roads, viaducts and busy vehicle corridors,” explained Professor Gan Woon-Seng, who teaches audio engineering at National Technological University (NTU). Additionally, “most residential buildings are high-rise, creating multiple reflection canyons where noise bounces between buildings”.

Moreover, in the city’s hot climate, many residents prefer open-window living, allowing more noise into houses.

To understand how this never-ending noise invades homes, we collaborated with Prof Gan and senior research engineer Santi Peksi from NTU’s Smart Nation Translation Lab. With their help, we recorded sound levels inside 25 residences across the city. All the participants live near a source of steady traffic, such as an airport, a major road or the MRT .

The recordings captured the noise landscape in each home. To make sense of what we found, we first need to talk about decibels.

Decibels are used to measure the intensity of sound. Louder noises correspond to higher decibels. A quiet library is roughly 40dB, while drilling at a construction site is about 76dB. Hear for yourself.

The following clips won’t play at their actual decibel levels; that depends on your device and volume settings. What matters is the relative difference: Listen to how much louder one environment is compared to another.

The tricky thing about decibels is that they increase not linearly, but on a logarithmic scale. That means when noise jumps from 20dB to 40dB, the sound is not twice as loud, but 4 times as loud. Because of this, little changes in decibels make a big impact.

According to the WHO, excessive noise can cause an array of unwanted health problems – from sleep disturbance and depression to hypertension and adverse birth outcomes – so the organisation has established safe levels of average exposure. For traffic noise, it recommends a daily average of less than 53dB, and less than 45dB for aircraft noise.

Singapore, too, has determined safe levels of noise. The National Environment Agency (NEA) suggests average indoor noise levels should be below 57dB.

“These benchmarks were established by referencing international standards,” said an NEA spokesperson.

The slightly lower WHO level can be tough to achieve in Singapore. “The WHO road traffic noise thresholds are derived largely from European exposure datasets,” Prof Gan explained. “When applied to dense Asian cities, structural, climatic and land-use realities make these thresholds systematically more difficult to achieve, even with strong governance and high-quality infrastructure.”

With the help of Ms Santi, ST analysed up to six hours of recorded noise in each of the 25 homes we visited. A true comparison with WHO and NEA standards would require a full day of recording. Nonetheless, during the hours we visited, the noise in many homes reached levels that, if sustained throughout the day, would exceed both the WHO and NEA safe noise thresholds.

These numbers tell one story. But to really understand what living with excessive noise means, you need to hear it for yourself.

The noise from road traffic and a waterfall can be the same volume, but one sounds peaceful, while the other is intrusive. The difference isn’t in the loudness, but in how our brains interpret the sound.

“Although noise metrics such as decibels provide standardised physical quantification of sound energy, human response to noise is fundamentally subjective,” explained Prof Gan. “Two sounds with identical sound pressure levels can evoke very different perceptions.”

Psychoacoustic researchers have identified several metrics, beyond just volume, that contribute to what makes a noise annoying. Two important ones are sharpness and roughness.

Roughness describes how grating or buzzing a sound feels. It is caused by rapid fluctuations that make a sound harsh or unpleasant. Sharpness, meanwhile, measures how piercing or shrill a sound is.

Excessive noise isn’t just annoying, it’s a serious health concern. According to WHO, noise from road traffic is the second-most harmful environmental stressor, behind air pollution.

“When something stresses you, it affects the immune system,” said Dr Omar Hahad, researcher at Germany’s University Medical Center of Mainz. “And when this is disturbed, literally every organ’s system is affected.”

Noise pollution can cause hearing damage, poor sleep, depression and anxiety. It can also contribute to heart disease, dementia, diabetes, increased infection rates and Alzheimer’s.

“We see that even one night of traffic noise increases vascular dysfunction, increases heart rate and blood pressure, and increases stress hormone release,” said Dr Hahad. These consequences are found in both healthy and unhealthy patients alike, but are worse in older populations and those with existing risk factors.

Because of these widespread health effects, some researchers have started referring to noise pollution as the “new second-hand smoke”.

“Second-hand means that, even if you’re not smoking, you’re affected by it,” said Dr Hahad. “Like (with noise) when there are night flights and a lot of traffic – you’re not responsible for that, but you’ll get affected by it.”

And it gets more complicated. Dr Hahad said noise pollution affects not just individuals’ health, but also their health behaviour. “When you’re exposed to noise, you’re less physically active, you tend to take alcohol and cigarettes because people are looking for easy coping pathways.” These behaviours, in turn, also increase health risks.

Many of those we surveyed said they actively take measures to combat the noise. The most common was simply closing the window. But it’s hard for individuals to tackle the root problem.

“We, as healthcare providers, cannot reduce the noise levels of our patients, so we need political energy to reduce this,” said Dr Hahad. “You could say ‘have a better diet’ and ‘be more physically active’, but you cannot tell a patient to lower their noise because they cannot move (homes). This needs collaborative action between healthcare providers and lawmakers.”

Singapore has a handful of military air bases and two commercial airports, including Changi – the world’s 15th largest by passenger numbers – which makes managing aircraft noise a big job.

Ms Jean Yee, director of air navigation services policy at the Civil Aviation Authority of Singapore, said: “Singapore adopts the International Civil Aviation Organization’s balanced approach to aircraft noise management.” This means departing planes at Changi use special routes that avoid flying over noise-sensitive areas during take-off. Between midnight and 6am, arriving aircraft must use quieter engine settings, unless necessary, and the runway closest to residential areas is closed entirely.

Roads occupy 12 per cent of Singapore’s total land area. To reduce noise from this extensive network, Singapore’s Land Transport Authority (LTA) installs barriers along expressways and flyovers, and uses special low-noise pavement on some expressways.

“When implementing traffic noise mitigation measures, our key considerations include road noise levels in relation to proximity of residential developments and noise-sensitive developments,” said an LTA spokesperson. “Mitigation measures are prioritised in areas where noise levels exceed acceptable thresholds, particularly near homes, schools and healthcare facilities.”

LTA also manages noise mitigation measures for the MRT. Noise barriers are installed along parts of the MRT located near homes, and also where sound levels exceed NEA guidelines. LTA also works with manufacturers to fit trains with noise-dampening wheels and modify elevated tracks to better absorb vibration and noise.

For new residential developments, NEA has implemented noise impact guidelines and assessments, which ensure new buildings keep out as much traffic clamour as possible.

The agency also suggests measures that individuals can take: “To further reduce noise levels, residents may consider additional measures such as closing their windows, installing noise curtains or using laminated or double-glazed windows.”

Despite the many noise mitigation measures implemented by the city, there is more that can be done. “Agencies can use noise mapping, predictive modelling and real-time sensor networks to guide interventions,” Prof Gan suggested. This kind of monitoring system could identify shifting noise hot spots.

He also said Singapore could establish urban design guidelines that don’t just aim to reduce decibels, but also consider psychoacoustic metrics like the variety and pleasantness of the soundscape.

For now, many Singaporeans will have to accept that dense urban living comes with a soundtrack. But, as the city and researchers have shown, solutions exist. With continued collaboration between health experts, urban planners and policymakers, Singapore can ensure that its residents don’t have to choose between city living and a good night’s sleep.