New study finds planted front gardens can be up to 6°C cooler than paved plots, while revealing a more complex picture for roadside air pollution.
Paving over front gardens could mean losing more than a splash of colour and some greenery. Research carried out at homes beside busy London roads suggests that gardens with hedges and planting could help neighbourhoods combat urban heat.
The University of East London (UEL)-led study explored how the space between the pavement and the front door could help Londoners cope with heat and traffic pollution, recording summer temperatures up to 6°C lower in planted gardens than in paved plots.
Working with the University of Surrey, the team monitored seven front gardens in Enfield and Barking and Dagenham across four seasons, comparing paved spaces, lawns and gardens with hedges and other vegetation. Monitoring included gardens close to the North Circular and focused on neighbourhoods where social deprivation and poor air quality overlapped.
Lead researcher Dr Karina Corada-Pérez, of UEL’s Sustainability Research Institute (SRI), said:
“This year’s heatwaves have brought the need to keep our cities cool into sharp focus. When we think about keeping cities cool, we tend to picture parks and street trees. But the space outside our own front door deserves attention too.
“We recorded a striking summer temperature difference between planted and paved gardens. That raises an important question about what we could be losing when our front garden is replaced with hard surfaces.”
Across the summer measurements, paved gardens were on average 4.6°C warmer than gardens with hedges and mixed planting, and 3.4°C warmer than lawn gardens.
Plants can provide shade and release water vapour, cooling their surroundings. Hard surfaces, by contrast, absorb and store heat during the day and release it slowly overnight, which can make summer nights warmer.
Air quality measurements painted a more complex picture. Some hedged gardens recorded substantially lower concentrations of inhalable particles during summer and winter, but the benefits varied between locations and seasons. In spring, some recorded higher pollution levels. Lawn gardens generally had comparatively low and stable particle concentrations. The reasons for the spring increase are not yet clear. It may reflect seasonal factors such as pollen release, changes in the hedges or conditions specific to each site. These factors were not measured directly in the study, so their role remains uncertain.
These patterns suggest that hedge structure, airflow and local conditions could influence the benefits of planting, rather than greenery automatically providing a pollution shield.
The researchers say larger studies are needed to establish which garden features offer the greatest benefits, as the small sample and differences in monitoring dates mean weather and background pollution may also have influenced the findings.
Dr Corada-Pérez added:
“A front garden may be small, but it is part of the environment people experience every day. Urban planners need to recognise the role these spaces can play in creating greener, more comfortable neighbourhoods. Understanding what these spaces can offer could help us make better decisions about the places where we live.”
The research is published in the journal Urban Forestry & Urban Greening.
