The Climate Change and Health Reference Unit of the Carlos III Health Institute (ISCIII) has published research that reveals that the ‘urban heat island’, added to global warming due to climate change, can affect people’s health by increasing the risk of hospitalizations and deaths.
The urban heat island effect is called a meteorological phenomenon that results in an increase in temperature in urban areas, generally at night, attributed to factors such as the elements that give off the heat accumulated during the day, including materials present in the cities such as asphalt, building facades and air conditioning devices.
The main results of the work indicate that the thermal heat island effect is observed mainly in the minimum temperatures, that is, at night, and not so much in the maximum ones, and that its values translated into an increase in minimum temperatures oscillate a lot depending on the city: For example, in Murcia it is reflected in 1.2 degrees Celsius (ºC) more in the city than in the periphery, while in Valencia it is 4.1 ºC more.
In addition, the authors have confirmed that the relationship between the risk of disease and death in inland cities occurs with maximum temperatures -the daytime-, while this association, in coastal cities, appears with the minimum temperatures -the nocturnal-.
INFLUENCE OF THE GEOGRAPHICAL LOCATION AND CHARACTERISTICS OF EACH CITY
The results indicate that the geographic location and the characteristics of each zone are key to the possible effect of the urban heat island, which suggests a need to carry out local studies to determine the greater or lesser importance of the urban heat island according to the type town.
One of the novelties of this work is that it uses data from meteorological observatories, one located within the city and the other on the periphery, which has made it possible to confirm the thermal differences of the urban heat island effect: the highest values of difference Between the observatory located in the urban interior and the one located outside, they have a maximum daily range of up to 11.2 ºC in Valencia, 9.5 ºC in Murcia and 7.1 ºC in Madrid.
They also point out that in inland cities such as Madrid and Murcia the thermal island can generate ‘discomfort’ in people, but it has fewer possible effects on health, since it does not affect deaths or urgent hospital admissions in the short term.
On the other hand, in coastal cities such as Valencia, a greater risk to health is identified, with an increase in minimum daily urban temperatures related to deaths and admissions. In the case of Barcelona, both the minimums and the maximums seem to have an influence.