Noise is one of the biggest health hazards in cities
According to the World Health Organisation, (WHO/Europe) noise from traffic has a detrimental effect on almost one in three people in Europe, and one in five are regularly exposed to noise levels at night that are high enough to impair health.
Noise is one of the most important environmental risks to health and continues to be a growing concern among policy-makers and the public alike. Based on the assessment threshold specified in the Environmental Noise Directive of the European Union (EU), at least 100 million people in the EU are affected by road traffic noise, and in western Europe alone at least 1.6 million healthy years of life are lost as a result of road traffic noise.
Noise is an important public health issue. It has negative impacts on human health and well-being and is a growing concern. The WHO Regional Office for Europe has developed guidelines, based on the growing understanding of these health impacts of exposure to environmental noise.
Recommendations
Road Traffic Noise
For average noise exposure, the Guideline Development Group (GDG) strongly recommends reducing noise levels produced by road traffic below 53 decibels (dB) Lden, as road traffic noise above this level is associated with adverse health effects.
For night noise exposure, the GDG strongly recommends reducing noise levels produced by road traffic during night time below 45 dB Lnight, as night-time road traffic noise above this level is associated with adverse effects on sleep.
To reduce health effects, the GDG strongly recommends that policy- makers implement suitable measures to reduce noise exposure from road traffic in the population exposed to levels above the guideline values for average and night noise exposure. For specific interventions, the GDG recommends reducing noise both at the source and on the route between the source and the affected population by changes in infrastructure.
The Electrification of Public Transport – Changing Sound
Mark Simms, R&D Director, Ventac“In the past on diesel vehicles it was all about the overall decibel level. With electric vehicles it’s all about the whines and whirrs: it’s much more about the sound quality. We have the capability to test that – the ranged tonality, the sharpness, the roughness, all these characteristics.”
According to our R&D Director, Mark Simms, in terms of decibels electric PCVs and other vehicles are particularly quiet. Despite being more hushed, they can still emit sounds that are uncomfortable for passengers, giving off a ‘fingers on the blackboard’ quality if not properly dealt with. Decibels don’t really capture that, and at Ventac we can record and play back the noise we measured with the speed and rpm of the vehicle and pin down the acoustic problems and try to identify each source, whether its hydraulic noise, the cooling fans or the convertor. With electric it’s all about the individual noise sources. What we have found is when you have a large electric motor with a lot of torque, you can get some quite unpleasant whines out of it. You move from that broad rumble of the diesel engine to more discreet tonal noises. You can have nosies from the electric motor, a high frequency whine; the gear noise, again an intrusive whine; the hydraulics ; the road openness, passengers are conscious of cars passing by, as they can hear them more without the diesel engine. There’s a lot of difficult acoustic issues.
As well as the changing face of noise on electric vehicles, another challenge presents itself: “With electric vehicles there is always a focus on keeping weight minimal. Our engineers are conscious of any additional weights. We have moved from a more blanket approach to a target approach with noise reduction”.
The view a sound camera showing the source of noise on a vehicle base
In our acoustics laboratory, we use sound cameras to identify the source of problematic noisesLooking ahead electric vehicles and fuel cell vehicles will continue to be a major focus for Ventac, and we are trying to develop new products to meet the requirements of electric vehicles.
See the full guidelines for the European Union here: Environmental Noise Guidelines
If you are interested in learning more about Ventac’s commercial vehicle noise control solutions contact our R&D Director Mark Simms
