On February 17, the United Nations Environment Programme (UNEP) released their annual Frontiers report. This report takes a yearly look at emerging issues of environmental concern, and outlines the U.N.’s highly researched suggestions for ways to mitigate the effects of these issues. This year’s issues were the impact of climate change on phenology, the hefty impact of wildfires, and the one we here at NoiseNet are best equipped to talk about: the public health threats of increasing urban noise.
The Threats of Noise
Urban nuisance noise has received a lot of research over the past few decades, with troubling results. It’s well-known that long-term exposure to noise over 70 decibels (think heavy traffic) can cause hearing loss; sounds over 120 decibels (a jet taking off close by) can also cause immediate, irreparable damage.
But these are just the effects of noise directly on hearing. There is mounting evidence that noise has a powerful effect on our stress and sleep levels, which can cause a number of significant mental and physical health issues, including insomnia, depression, imbalanced hormonal regulation, coronary heart disease, and diabetes. A conservative estimate from the UNEP report suggests that long-term exposure to nuisance noise contributes to 48,000 new cases of ischemic heart disease and causes 12,000 premature deaths in Europe each year. 22 million Europeans suffer with chronic noise, and the elderly, pregnant women, and shift workers were found to be most at risk of noise-induced health effects
Studies outside of medicine and psychology are also finding serious effects stemming from unregulated urban noise. Many city-dwelling animals — but especially birds, bats, insects, and frogs — have been found to be altering their behaviours in response to increasing noise. In many European cities, local flocks of robins were observed singing more at night to avoid acoustic interference during the day. In Japan and the United Kingdom, urban-dwelling great tits sing at higher pitches than their forest-dwelling cousins — and are also much, much more aggressive. Many species of frogs have been observed slowing down their calls, and timing them to fit in the gaps between noise peaks.
These issues may seem like small potatoes compared to the human toll of noise, but these altered vocalisation and behavioural patterns can have severe knock-on implications for the urban environment. Potential mates may consider new vocalisation patterns less attractive, impacting reproductive success. If members of the species aren’t flexible enough in producing and receiving their signals, they could wind up extinct from their habitats entirely. This can severely impact the entire ecosystem of a city, causing increased problems with pests and plant growth as predators and pollinators die out — drastically decreasing liveability.
The Solutions To Mitigate Noise Pollution
The UNEP didn’t just outline the problems of urban noise without also offering potential ways to mitigate or even solve those problems. They collated a number of recommendations from the World Health Organisation and other research teams on methods for turning cities into healthier, more habitable soundscapes. Many of these solutions align very strongly with our goals at NoiseNet, so we’re excited to be seeing attention directed towards noise from some of the largest public bodies in the world. So what are they?
Many technological solutions are already in the process of being implemented globally to combat noise pollution. Digital road, rail, and air traffic management systems and shifts away from internal combustion engines are contributing greatly to the reduction of urban nuisance noise. Additionally, newer tech like internet-of-things noise monitoring networks and app-based public reporting systems are beginning to see small-scale use, and can become a powerful, scalable tool for governing bodies to use in managing noise.
Increased green spaces in urban environments work exceptionally well to absorb acoustic energy. Vegetated roofs, roadside tree belts, green bridges, and larger, more vegetated parks and quiet spaces allow people and animals positive places for rest and relief from noise. Natural sounds like flowing water, birdsong, and human conversation are proven to boost our mood and help calm many of the problems which arise from nuisance noise, and including them in urban planning considerations is paramount.
Many of the issues of urban noise can be reduced through the implementation of clever engineering solutions. Electric vehicles are beginning to see wider use, but at speeds of higher than 50km/h can still produce high noise levels from contact with roads — as a solution, the UNEP suggests porous asphalt, which can better absorb acoustic energy. Additional considerations like pathway planning, noise barriers, and insulative materials can powerfully break the chain of noise propagation.
Many cities across the world have begun to implement regulatory frameworks and legal requirements to address the sources of noise which are most cost-effective and straightforward to enforce. Some more forward-thinking cities are also establishing more radical, out-of-the-box solutions, such as Berlin restructuring their road networks around bike lanes, or London establishing an Ultra-Low Emission Zone. The UNEP and the WHO recommend further legislative action to establish and protect positive soundscapes like green spaces.
The 2022 Frontiers report covered a lot of ground in bringing the issues around nuisance noise to light — a lot more than we can cover here. If you’re interested in reading the whole report, you can find it here. NoiseNet is excited to be able to contribute to the development of new and innovative technological solutions to many of the issues the UNEP has found — check back soon to learn more about our devices and the ways they’re being used in locations around the world. If you’re interested in learning more about NoiseNet, check out https://www.noisenet.com/.