Highlights

• Made a small-area analysis of greenspace exposure and heat-mortality associations.

• Examined which type and location of greenspace matter most in heat health risk reduction.

• Unlike grassland, forests yielded significant health benefits under heat.

• Greenspace, especially forests, within a 1 km radius of residents matter most.

• More apparent effects were observed for greenspace nearby than area-level exposure.

Our findings suggest that greenspace, particularly nearby forests, may significantly mitigate heat-related mortality risks.

The authors believe that particular interventions in residential greenspace within a walkable distance (around 1000 m) could effectively reduce heat exposure and vulnerability, thereby, decrease the likelihood of mortality from heat. If these findings are replicated, such implications will be of importance to urban planners and designers as they seek to achieve maximal health benefits through informing measures of modifiers to specific pathways and threshold effects for each.