Fighting noise and heat in the city
City dwellers: the first victims of noise and summer heat
- 37 million Europeans are exposed to sound levels that are harmful to their health and 11% of Parisians endure sound levels above the regulatory limit of 68 decibels. Why? Mainly because of road traffic.
- At night, roads—mineral, impermeable surfaces—release the energy they accumulate throughout the day: they are Urban Heat Islands (UHI). In cities, this phenomenon is amplified, given the vast extent of these surfaces. The outcome? During periods of strong heat, city dwellers withstand temperatures that are higher than elsewhere. The increases in temperature could exceed 8°C by 2100.
- – As a result, health is affected, leading to problems such as sleep disorders, breathing difficulties, hearing problems, stress, and more.
The response: a range of innovations
- encouraging soft modes of transport and electric engines,
- planting more greenery,
- and improving the thermal and acoustic properties of materials used in roads.
The undertaking: a principled partnership
As a proposal specially selected in 2016 by the EU’s funding programme LIFE, this project enjoys funding from the European Commission amounting to around 1.3 million euros (of which almost 700,000 euros are for Paris City Hall).
Innovative surfacing produced by Colas and Eurovia
They are designed to improve the acoustic and thermal properties of conventional surfacing while offering good mechanical properties.
What they have in common:
- use of pale aggregate helps reflect light (albedo effect) and reduces Urban Heat Islands (UHI);
- porosity of the aggregate helps retain more water and facilitates evaporation of this water, therefore cooling down the air during heat waves;
- porosity is also an attribute that fights noise pollution by trapping road noise.
Puma® (Eurovia): hot-cast, pale-aggregate asphalt.
BBphon+®: pale-aggregate acoustic surfacing.
SMAphon®: pale-aggregate urban surfacing.
The aim is to decrease the road noise and improve acoustic absorption by 20%. SMAphon also includes highly pale aggregate with water-retention characteristics that limit the extent to which the road heats up under solar radiation.
Assessment and measurement of three pilot sites
Concrete figures after three years
An actual temperature decrease of around
An apparent temperature decrease of around