Sound Solutions

Designing quieter experiences in and around transport solutions

As the impact of noise pollution becomes more widely understood, citizens are calling for governments and companies to address excessive noise produced by industrial practices and transport.

Nearly 2.5 billion people worldwide127 - or 1 in 4 people - will be living with some degree of hearing loss by 2050. Agerelated hearing loss was the third-largest source of global years lived with disability in 2019 and the leading source for adults older than 70128 years of age. In China, the number of people aged 65 and above who experience hearing difficulty is expected to have exceeded 50 million129 in 2021.

Studies have shown that hearing loss can lead to social isolation and loneliness130 at all ages due to decreased participation in activities and reduced social circles. This can occur due to increased avoidance of potentially embarrassing social situations that arise from an impaired ability to comprehend auditory information131. Social isolation can significantly impact the psychosocial and cognitive health of older adults. A lack of interaction and loneliness can lead to cognitive decline as well as worsening mental health132, facilitating a gateway to depression. Noise pollution can also lead to several other health effects including, a greater risk of ischaemic heart disease, hypertension133 , sleep disturbances134, annoyance and cognitive impairments135 .

The impact of the Covid-19 pandemic in increasing collective awareness of noise pollution cannot be understated. As the world went into lockdown, people, transport and industry all stopped, bringing with it a new quiet landscape136 . As a result, people reported that bird songs had gotten louder137 when, in fact, the bird song had gotten quieter.

Road traffic noise is now one of the leading causes of noise pollution globally. The European Environment Agency estimates that 100 million people in EU states are exposed to road traffic noise above 55dB138 (the EU’s daily exposure threshold), and of these, 32 million experience very high noise levels (above 65 dB). Noise data collected from 322 cities across China in 2016 showed the average day-time sound level of urban road traffic is 66.8dB139, accounting for 21.7% of noise sources.

Mobility solutions that help prevent hearing damage and make it easier for those with hearing impairments to lead comfortable, healthier lives will become highly sought after.

© Pawel Czerwinski

MICRO TREND

© Silentium © WEY

CASE STUDY Noise Cancelling Technology Brought To Cars

In an attempt to escape the din of modern day noise pollution, headphones have become a common feature of citizens daily lives140. In recent years, Active Noise Cancelling (ANC) technology has become an increasingly popular audio feature, with the likes of Apple, Xiaomi, Huawei all releasing audio devices with this function.

As citizens’ look for an escape from noise, companies are exploring how noise cancelling technology can be used to reduce noise inside of cars.

WEY a Chinese car brand produced by Great Wall Motor141, launched their VV7 model in 2017. As of 2020, the VV7142 has been equipped with a Harman highperformance engine noise reduction controller equipped with active noise reduction technology.

Molex, an electronics solutions provider, has recently announced an accelerometer-based Road Noise Cancelling (RNC) sensor143. These sensors are aimed at combating unwanted road, wind and HVAC car noise while reducing low-frequency sounds that increase driver fatigue.

Silentium144, a company that specialises in the development of noise reduction products and solutions, has recently announced its partnership with Hyundai Mobis as its preferred Active Road Noise Cancellation145 (ARNC) technology supplier, following its successful partnership with Jaguar Land Rover146 .

CASE STUDY Aerodynamic Acoustics

Transport solutions, especially those powered by combustion engines, create a lot of noise pollution. Electric vehicles, although better, still create noise pollution from wheel friction and aerodynamic turbulence147 .

Reducing drag has become a key focus area for automakers looking to increase the range of electric vehicles.

Unveiled at CES 2022, the Vision EQXX148 is Mercedes-Benz latest solar-powered concept car, capable of exceeding 1,000 kilometres (648 miles) on a single charge. The car’s slender teardrop shape has been designed to reduce aerodynamic drag, and Mercedes have a “benchmark” drag coefficient of 0.17 based on a 140km/h wind tunnel test — an improvement over the EQS’ recordsetting 0.20 drag coefficient. The car has also been designed with narrower rear wheel tracks to allow the air to flow more efficiently and transparent external covers on the wheel to prevent air turbulence.

In similar efforts to reduce aerodynamic drag, Audi and Honda introduced camera side mirrors to their Audi e-tron and Honda E vehicles. Instead of using large reflective panels, the cars are equipped with smaller aerodynamic cameras, streaming video to in-vehicle displays.

While not intentionally designed to reduce outward noise pollution, by improving the aerodynamic qualities of their car, these companies are reducing external noise pollution, thus helping to reduce the impact on citizens’ health and longevity. Numerous studies have shown that exposure to aircraft noise can have adverse effects on the health of people living near airports including, annoyance, sleep disturbance, cardiovascular disease including hypertension, altered cognitive performance in children, and disruption in hormonal rhythm.

Increasingly, Chinese citizens will face exposure to aircraft noise as the country ramps up its domestic and international aviation market. As part of its 14th FiveYear Plan 1, China aims to have 400 civilian transport airports by the end of 2035149, an increase of 150 compared with the number at the end of 2020, meaning that China will average around ten new airports each year by 2035.

Researchers in China are exploring how to reduce aviation noise in the future. In a recent study150, researchers from Xi’an Jiaotong University in China used noise calculation and analysis software to study airfoils with characteristics reminiscent of owl wings.

In a statement study author, Xiaomin Liu said, “Nocturnal owls produce about 18 decibels less noise than other birds at similar flight speeds due to their unique wing configuration”.

Using this point of reference, the researchers designed aerofoils with asymmetric serrations, capable of reducing noise more than symmetric variations.

The conflict which arises from a growing desire and necessity to travel, with growing evidence of adverse impacts that noise pollution has on longevity, presents companies with an opportunity to innovate. Those seen to be addressing this issue earlier will be the ones to capture citizen attention.

© Mercedes-Benz

© Honda © Pete Nuji