On a warm summer morning in Guildford, a researcher walks through Stoke Park with a sensor-laden backpack, weaving between shaded lawns and leafy paths—each step capturing invisible benefits radiating far beyond the park’s borders. This 52-hectare green heart, the largest in the Surrey town, is doing far more than hosting picnics and dog walkers: it’s actively cooling the city, cleaning the air, and quieting the urban roar. A groundbreaking study by the University of Surrey’s Global Centre for Clean Air Research (GCARE) has now quantified just how powerful that impact is. As cities grapple with rising temperatures and pollution, the findings offer concrete evidence that parks are not just pleasant spaces—they’re essential infrastructure for climate resilience.
The research, led by Soheila Khalili and Professor Prashant Kumar, used high-frequency mobile monitoring across five transects to measure air temperature, PM10 pollution, and noise levels both inside Stoke Park and in surrounding built-up areas. The results were striking: morning PM10 levels—tiny, harmful particles linked to respiratory illness—were 11% lower within the park than in nearby urban zones. Air temperatures followed the same trend, registering 6.5% cooler in the park during the morning and staying several degrees lower throughout the day. But perhaps most surprisingly, these benefits don’t stop at the park’s edge. For every 100 meters outward into the city, temperatures rose by more than 0.5°C, with measurable cooling effects extending up to 300 meters (nearly a kilometer in all directions) from the boundary.
Noise pollution, too, was significantly reduced. Inside the park, sound levels dropped by 5.41 decibels—a difference perceptible to the human ear and equivalent to removing nearly half the noise intensity. Even more impactful was the effect on how heat feels to the body. Using physiologically equivalent temperature (PET), researchers found that tree-shaded and grassy areas made conditions feel up to 8.5°C cooler than adjacent streets, a dramatic improvement in thermal comfort during peak heat. Fisheye lens images confirmed that sky visibility—and thus heat exposure—was drastically reduced under tree canopies, reinforcing the role of shade in urban cooling.
These findings aren’t just about one park in one town. They offer a replicable model for cities worldwide seeking nature-based solutions to climate stress. "Our work shows that parks can bring measurable cuts in heat, pollution and noise both inside parks and across surrounding neighborhoods," says Professor Kumar. With urban green spaces under constant pressure from development, this data strengthens the case for protecting and expanding them—not as luxuries, but as vital tools for public health. As temperatures rise and cities densify, the quiet, leafy calm of a place like Stoke Park may be exactly what keeps communities cooler, healthier, and more resilient.