Deepak Dubey moves cases of bottled water onto a trolley at the back of the SuperValu on Ballymun Road.
He lives down the street, near the Garda station, and is working on a master’s in cloud computing at DCU. He likes to study at home.
“In the afternoon time, they come up with their motorbikes and they make a lot of noise. It’s difficult for us to study in that time also … Sometimes the noise is too loud actually,” Dubey says.
“When you close the window you can’t hear the noise of the buses, but you can hear the noise of the bikes, still.”
Ballymun is a noisy spot in the city, according to figures released by Dublin City Council’s Ambient Sound Monitoring Network (ASMN). Average ambient sound levels around the city have been on the rise since 2012, both during the day and at night.
This isn’t surprising to Christine McLoughlin, working behind the till at the front of the shop. She’s lived in Ballymun all her life and says she’s so used to the traffic noise, she tunes it out.
“I’d be used to the sirens and stuff, and the helicopters, and the planes from the airport … Somebody else who didn’t live in Ballymun would duck, the planes fly so low. I’m used to it.”
Ambient Sound
Just down the road from SuperValu, outside Ballymun Library, is one of the 14 monitors the ASMN uses to measured sound all day, every day.
There’s a steady flow of traffic going up and down Ballymun Road, even though it’s 7:30pm and rush hour is over. Dublin Buses chug by – the 17a and the 13.
Cars sail in and out of the row of parking in front of the library, full of children bound for the Setanta GAA Club next door. Voices float out of the apartments across the road.
The type of sound the monitors track isn’t “nuisance” noise – a neighbour’s dog barking or a loud rock concert – it’s “the on-going, ambient mix of sound right throughout the city”, said Brian McManus, at a council meeting last week.
Sound monitors are spread throughout the city to get a representative mix of different sounds, said McManus, who was head of the council’s Traffic, Noise, and Air Quality Unit that day, but has since retired.
There’s one on Bull Island, because it’s a designated quiet area under the Environmental Noise Regulations, meant to preserve and protect sound levels. There’s another one on Ballymun Road, “one of the busier roads within the city”.
Sound vs Noise
In 2018, both Bull Island and Ballymun recorded sound levels of 59 decibels at night, two of the highest night-time averages in the city.
But high sound levels from wind, the tides, and wildlife on Bull Island aren’t the same as high noise levels from road or air traffic.
“Noise” can be defined as unwanted sound, McManus said. “All sound is not noise, and all sound from different sources can have different impacts.”
Aircraft noise is more annoying than road noise, which is more annoying than rail noise. “You have to see where it’s coming from … It all has an impact on how people react to sound.”
The monitors picked up some unsurprising patterns: sound levels increase during peak commuting hours on weekdays, and are higher at night during the weekend.
Getting Louder
The average ambient sound levels across the city’s whole sound-monitoring network increased four decibels between 2012 and 2018.
Daytime levels have gone from an average of 57 decibels to an average of 61 decibels during that time, and night-time levels have increased from 52 to 56 decibels.
“Our feeling is that increase is partly due to different weather conditions,” McManus said. When you strip that out, most sites have been reasonably consistent over the last five years, he said.
Twenty-two percent of people in the city are being exposed to undesirable sound levels, especially at night, and traffic noise is the main culprit, according to the council’s Noise Action Plan 2018–2023.
Still, an average night-time decibel level of 56 isn’t exceptionally high, says Richard Neitzel, associate professor in the School of Public Health at the University of Michigan.
Neitzel researches the role noise plays in public health. His frame of reference is cities in the United States, but he says a four-decibel increase over a six year period “doesn’t seem exceptional”.
“But it does suggest that, as the city continues to grow over time, as it almost certainly will, are you going to see a four decibel increase every six years?” Neitzel says.
“Meaning that 20 years from now, it’s going to be noticeably noisier? That’s what we want to avoid, of course,” he says.
What’s Causing the Increase?
“The dominant sound emissions within the city are from traffic,” said McManus, of Dublin City Council.
That’s typical of cities, says Neitzel, of the University of Michigan, who researches the role noise plays in public health.
Transportation comprises the primary sources of ambient noise in most cities, he says, including road, air and rail traffic. Ambient noise could also include things like construction, industrial noise from factories, and public venues for entertainment and sporting events.
“On the decibel scale, like we’re dealing with here, a three-decibel increase would be equivalent to basically a doubling of the intensity of the sound,” he says of the four-decibel increase in Dublin.
“So you could think of that as basically twice as much sound intensity in 2018, actually a little bit more than twice, than there was in 2012. So that can sound like a pretty impressive change.”
But the human ear doesn’t work on a decibel scale, he says. Ears don’t perceive something to be twice as loud until it’s about a 10-decibel difference.
“From an individual perspective … it would be an almost imperceptible change. But from the perspective of, ‘How much sound are we putting out into the environment?’ it’s actually a pretty considerable change,” he says.
It’s a trend related to the “global phenomenon of urbanisation”, Neitzel says. Population density in cities is on the rise.
“While that has a lot of health benefits from a sustainability perspective, it almost always results in increased noise levels. You simply have more going on in the same amount of space,” he says.
Public health
The average levels in Ballymun for 2018 – 66 decibels during the day and 59 at night – are reasonably high, Neitzel says.
“[I]f I was a student in a classroom right next to that Ballymun monitoring station, those noise levels are almost certainly high enough that they would start interfering with my ability to learn in school,” Neitzel says.
There are a number of studies that link noise to an array of health impacts, Neitzel says, including high blood pressure, increased risk of stroke, and increased risk of heart attack.
Night-time noise can lead to sleep disruption, which can lead to those cardiovascular issues, he says. “So in addition to being tired and fatigued from not sleeping, you may also be at increased risk of having a heart attack.”
Neitzel says there’s also evidence that people exposed to more noise, regardless of time of day, are more at risk of mental-health issues like depression.
“So the hypothesis is that when you’re exposed to noise, it’s a general stressor on your system,” Neitzel says. And that sleep disruption, along with the effects of that stress, can bring an array of health problems.
Solutions
At last week’s meeting, Green Party Councillor Ciarán Cuffe said he was struck by the increase in average night-time noise levels from 2012 to 2018.
“In effect, that’s at least a doubling of the intensity of the noise, if you could call it that. I would have thought that’d be a matter of significant concern,” Cuffe said.
Cuffe asked the council to consider its options to reduce noise. He suggested using more low-noise asphalt to resurface roads, and reducing speed limits on arterial roads from 50 to 40 kph.
In fact, said McManus, the council official, the Noise Action Plan 2018–2023 already contains a commitment to install low-noise road surfaces where feasible. And out of all the council’s road surfacing last year, 41 percent was with a particular kind of low-noise road surface – stone mastic asphalt.
In terms of reducing speeds, McManus said, a sound assessment before by-laws reducing speed, didn’t find any reduction in decibel levels when the speeds went from 50 to 30 kph.
Cuffe had other ideas on how to reduce noise in the city. “We could also look at our own fleet of street-cleaning equipment,” he said.
There are changes the council is pushing for that aren’t explicitly meant to reduce noise, but which will help.
“Along with the climate change strategy and so forth, tackling traffic in relation to emphasis on walking, cycling, and use of public transport is a key factor in trying to abate sound levels as well as improve climate change and air quality,” McManus said.
On a larger scale, as jet-engine manufacturers make their engines quieter, and drivers switch from internal-combustion engines to electric ones, that should help too, Neitzel, of the University of Michigan, says.
“The other thing is, I think city planners have an opportunity as they’re developing or redeveloping cities to start to incorporate noise into their assessment,” he said.
Orienting buildings so residents have the quietest possible night-time noise levels, and making sure people have access to sporting venues but they aren’t located where they’ll annoy people living around them, would help, Neitzel says.
He says that if the noise rates in Dublin keep increasing at their current rate, people will definitely start noticing. “It would make it less livable, potentially, from a quality-of-life perspective,” he said.