More than a quarter of Greater London greenspaces exceed WHO traffic noise guidelines

Analysis of greenspaces in the Greater London area by University of Leicester scientists has shown that 28% are affected by road traffic noise above the guidelines advised by the World Health Organization.

Despite being seen as oases of calm in urban environments, the new study by the University’s Centre for Environmental Health and Sustainability published in the journal Health & Place suggests that many of these greenspaces may not benefit the health and wellbeing of their users as much as they could.

A significant body of evidence shows that greenspace is beneficial to wellbeing by contributing to physical activity and social interaction, promoting biodiversity, and helping to regulate greenhouse gases and elevate urban heat. Urban greenspaces have potentially restorative qualities which, combined with the absence of urban noise, can promote mindfulness and reduce annoyance.

However, unwanted environmental noise can potentially undermine these benefits. This study, caried out by researchers funded by the National Institute for Health and Care Research (NIHR) Leicester Biomedical Research Centre (BRC), investigated the variability of noise levels across Greater London’s greenspaces and compared these with the World Health Organisation's (WHO) Regional Office for Europe guidelines on environmental noise. These recommend that road traffic should not exceed 53 decibels (dB) averaged across a 24 hour period or 45dB at night.

Data on greenspaces in Greater London area was taken from the Ordnance Survey's (OS) ‘Open Greenspace’ data portal for the year 2019. This included 2,532 unique greenspace areas that cover a combined area of 232.3 km2, or 14.8 % of the city's surface. These greenspaces are used for a range of purposes, such as public parks and gardens, through to allotments, playing fields and other public uses.

Noise levels from major and minor roads were modelled across those 2,532 greenspaces for the daytime and evening period from standardised estimates calculated using European Commission Common Framework for Noise Assessment (CNOSSOS-EU) methods. This was adjusted to account for sound decay at points further from roads, resulting in an average noise level for each greenspace.

Analysis found that 28 % of greenspaces in London exceed equivalent road noise guidelines level, which were derived from the 53 dB 24-hour WHO noise guideline. Noise levels in greenspaces ranged from 35 dB – 74 dB for the daytime period and 35 dB – 71 dB for the evening period. Highest noise levels were found in the Central London district of Westminster. The study was led by Kathryn Adams, PhD student in the University’s Centre for Environmental Health and Sustainability.

Kathryn said: “Even though noise is subjective, noise exposures can still cause negative health impacts, regardless of whether you're aware of it or not. When we look at noise exposure, most studies look at noise at home location. There are no studies that have looked at noise at any other spaces, and specifically green spaces even though that's where we do our leisure activities or where we can get time out from urban stressors. We go to green spaces to relax and have tranquilly, but if your exposure to traffic noise is high it can actually detract from that.”

Kathryn’s research has also been analysing how equitable noise levels are in the capital. Large portions of Greater London experience significant deprivation, so if more deprived areas have greenspaces with high levels of exposures to road traffic noise levels then residents are more likely to experience exacerbated health outcomes. However, the picture from her research is more nuanced than this.

Kathryn adds: “Noise is very localised and depends on the geographical location. There are large inequality gradients for air pollution, with more deprived areas experiencing higher levels. When you look at overexposure to noise there is not such a clear relationship between deprivation and noise. In this study, we looked at London. But because noise is so understudied, we don't actually know what the distribution of exposures is like in other cities.”

Professor Anna Hansell, director of the Centre for Environmental Health and Sustainability, said: “Green spaces are important for mental health and provide spaces for physical activity and children’s play. We need to protect these areas from high air pollution and noise to maximise the benefits to health, particularly where both air pollution and noise levels are high as these both have adverse effects on health that may interact.”

The NIHR Leicester BRC is part of the NIHR and hosted by the University Hospitals of Leicester NHS Trust in partnership with the University of Leicester, Loughborough University and University Hospitals of Northamptonshire NHS Group.

For more information about the NIHR Leicester BRC visit www.leicesterbrc.nihr.ac.uk

• ‘Inequalities in road traffic noise exposure levels in greenspaces in Greater London’ is published in Health & Place, DOI: 10.1016/j.healthplace.2025.103536 Link: https://doi.org/10.1016/j.healthplace.2025.103536
• Note: WHO guidelines recommend that road traffic should not exceed 53 decibels (dB) averaged across a 24 hour period or 45dB at night.The WHO guideline levels do not give specific values for daytime and evening time noise. Therefore, the researchers converted the 24 hour guideline level to an equivalent daytime (51.2 dB) and evening (49.7 dB) noise levels, using a standard published conversion method. This meant they could assess noise levels across greenspaces at the times people are most likely accessing these spaces.