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. 2025 Jul 11;15(1):25165.
doi: 10.1038/s41598-025-08574-2.

The impact of increasing urban surface albedo on outdoor air and surface temperatures during summer in newly developed areas

Donia Elgendy  1 , Osama Tolba  1 , Tarek Kamel  2
Affiliations

The impact of increasing urban surface albedo on outdoor air and surface temperatures during summer in newly developed areas

Donia Elgendy et al. Sci Rep. .

Abstract

This study investigates the influence of increasing road surface albedo on outdoor air and surface temperatures in residential areas, taking into account constraints on broader environmental modifications. Urban albedo, which is determined by spatial geometry and material reflectance, influences the amount of solar radiation bouncing back into the atmosphere. Field measurements were conducted on-site to document Air Temperature (Ta), Wind Speed (WS), Relative Humidity (RH), Mean Radiant Temperature (MRT) providing the basis for validating simulation models. The urban geometry was reconstructed from real site data and simulated using a hybrid modeling approach, combining Ladybug with Grasshopper for Surface Temperature (Ts), MRT, and Universal Thermal Climate Index simulations, and ENVI-met for Ta, RH, and WS simulations. ENVI-met outputs were integrated into Grasshopper to achieve high-accuracy environmental modeling. Results demonstrate that increasing pavement albedo from 0.12 to 0.50 reduced Ts by up to 12.94 °C at peak solar hours and lowered Ta by a maximum of 1.96 °C during the day. The research addresses a critical gap by focusing solely on altering material reflectivity without changing urban morphology or adding any canopies either structured or vegetation. The findings confirm that enhancing surface albedo is an effective method to reduce daytime heat trapping & accumulation, and shortwave radiation absorption which mitigate the Urban Heat Island phenomenon.

Keywords: Ladybug plugin; Reflective materials; Surface albedo; Urban Heat Island; Urban geometry; Urban morphology.

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Conflict of interest statement

Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Pavement’s thermal interactions with the surrounding environment.
Fig. 2
Fig. 2
Methodology flowchart.
Fig. 3
Fig. 3
Ariel view for the selected area before and after new urban regulations.
Fig. 4
Fig. 4
Modelling phases.
Fig. 5
Fig. 5
Grasshopper’s extensive parametric specification for outdoors surface temperature measurement, MRT, and UTCI.
Fig. 6
Fig. 6
The R-squared (R2) value between measured and simulated data for MRT.
Fig. 7
Fig. 7
The R-squared (R2) value between measured and simulated data Ta.
Fig. 8
Fig. 8
The instruments used in data collection for validation.
Fig. 9
Fig. 9
Air temperature comparison before and after new urban regulations.
Fig. 10
Fig. 10
Air temperature comparison between different surface albedo.
Fig. 11
Fig. 11
Comparison between surface temperature before and after new urban regulations.
Fig. 12
Fig. 12
The correlation of asphalt’s surface temperature between different albedo values.
Fig. 13
Fig. 13
The correlation between MRT during the day and albedo values.
Fig. 14
Fig. 14
The correlation between UTCI during the day and albedo values.
See this image and copyright information in PMC

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