Could an ultra-white paint cool the cities of the future?
This article is also available here in Spanish.

Could an ultra-white paint cool the cities of the future?

My list

Author | M. Martínez Euklidiadas

Could cities combat urban heat if they were painted white? Theoretically they could, and historically they have. Recently, Xiulin Ruan, a Purdue University professor of mechanical engineering, created the whitest paint on record, capable of reflecting 98.1% of sunlight.

Albedo, warm cities’ greatest ally

The narrow and white streets of the villages in Andalusia (Spain, above Malaga) are known worldwide. Oia, a village on the archipelago of Santorini, renowned for dazzling ships and also Ashgabat, the capital of Turkmenistan, famous for having the world’s highest density of buildings made from white marble, use similar mechanisms.

Hundreds of towns across the world have learnt to adapt over thousands of years, cladding buildings with marble, painting houses with whitewash, made of slaked lime or using minerals. By increasing the white area, they also increased the albedo, the solar radiation reflected by a surface. Dark surfaces absorb solar radiance, light surfaces reflect it.

The whitest paint in the world to cool buildings

The pigment developed by Xiulin Ruan and his team is capable of reflecting 98.1% of solar radiation. At the other end of the spectrum, the Vantablack pigment (the blackest shade of black) absorbs 99.96% of light.

In practice, painting buildings with the whitest shade of white -formally nanoparticles of barium sulfate– entails temperatures of around 4.5 ºC below exterior temperatures, and therefore lower use of temperature control systems, which require energy.

Can paint cool our cities?

These solar geoengineering proposals to cool large urban areas, may provide some relief to combat the heat island effect experienced in many cities, particularly if they are combined with large green areas, vegetation providing shade or sources of water.

It is not a cure, and sometimes it can even lead to conflicts —a completely white property will reflect, through the albedo effect, on to the building in front—, but with the help of other public policies, undoubtedly we would create more human cities.

ultrawhite paint 2

For example, a completely white building next to a black asphalt surface, without any elements to provide shade, is not smart. The asphalt will reflect on the building all day long and, regardless of how white the building is, it will get hot. Furthermore, the area will be unusable for pedestrians.

All that reflects is not snow…

In addition, white pigment technology is not particularly easy to apply compared with other white coloring. Although the idea is to use this pigment to cover entire cities and prevent them from getting warm, it is important to point out that the alternative use of conventional paint is much more convenient.

There are also other alternatives to reduce our dependence on air conditioning, other than color. Green roofs are a great example of heat dissipation which also cools the environment and the streets. Another example are roofs with water, although both options entail certain technical complications, such as damp issues.

Painting buildings white is another option

ultrawhite paint 3Daily Sea Surface Temperature

While writing this article, the city mentioned at the beginning of the same is experiencing an unprecedented heatwave, (the last of its kind dates back to 1942) and the Mediterranean has reached its highest ever recorded temperature (map).

In their adaptation to the climate crisis and in order to build more human cities, towns around the world are coming together to combat soaring temperatures.

Image |  Tabea Schimpf

Related content

Recommended profiles for you

VC
Vladimir Cuartas
Alcaldía de Palmira
NF
Nauman Farooq Farooq
Beyon Solutions
Head Smart ICT Infrastructure
RB
Rahul Bhatia
Adonisav
Country head sales and marketing \\nWe are OEM company for video conference solution.
VK
Vedant Kulkarni
DYPIEMR
NA
AI
Alexey Istratov
illumika
co-founder, designer
TM
Ted Mengers Mengers
Pyranak Design Group
CEO
SH
Sami Huuskonen
Tehomet - a Valmont Company
Design Manager
AC
Alex Champagne-Gélinas
PhD student in urban studies specialized on energy transition in ports and port regions
IQ
Isayo Quinto Neglia
Auna
Leader of Design and Construction of Clinics, health centers and other infrastructures
RD
Ruwan De Silva
Sripalie Contractors (pvt)Ltd
Managing Director Sripalie Contractors (pvt)Ltd A leading Building Construction Company in Sri Lank
LB
Leire Balzategui
Fundación Vitoria-Gasteiz Araba Mobility Lab
Innovation Technical Manager
MV
Milos Vranek
CGF
DZ
Dr Christina Yan Zhang
The Metaverse Institute
PA
pere armora
aykos healthcare
partner and director
SF
Siti Fairuz
Alauddin State Islamic University of Makassar, Indonesia
Just a Student
CO
Crina Oltean-Dumbrava
University of Bradford
Professor in Sustainable Built Environment
MC
Martin Canning
Evergreen Canada
DJ
Dario Junior
HAGNUS GROUP
CEO , FOUNDER AND OWNER
RK
Roland Krebs
superwien urbanism
Director
JK
Jerry King
Bentley Systems, Incorporated
Only accessible for registered users
This content is available only for registered users