Madrid is suffocating from ozone, a pollutant in the lower layers of the atmosphere resulting from the interaction of various gases under specific conditions of solar radiation. That's why its main impact occurs in spring and summer. The city of Madrid and the region as a whole are the Spanish territories with the highest degree of ozone pollution, both in isolated episodes and structurally. On the other hand, ozone levels have decreased on the Mediterranean coast, the Ebro Valley, the Cantabrian coast, and the Canary Islands.
The Spanish capital has reached this year the worst air quality levels on record.
In almost all monitoring stations, the levels have been above the limit value or target value for health protection (120 ㎍/m³ in 8 hours, a threshold that cannot be exceeded more than 25 times).
At a Community level, all stations have also surpassed the new legal target set by the EU for the year 2030.
In addition, more than two hundred instances of exceeding the threshold that requires informing citizens (over 180 ㎍/m³) in individual one-hour episodes have occurred jointly, without the City Council or the Community of Madrid effectively warning the population. This is indicated by the annual report released by Ecologistas en Acción.
“The situation in Madrid is worrying, pollution levels are on the rise, which contrasts with what we have seen this summer in the rest of Spain, where they are decreasing; and that's considering that the summer has been shorter,” says Miguel Ángel Ceballos, one of the study coordinators.
In the ranking, very prominent
The ranking of the most polluted areas in Spain is topped by Madrid. The threshold that obliges to inform the population about specific pollution episodes (more than 180 μg/m³) has been exceeded here a total of 203 times out of the 278 exceedances that have occurred in Spain overall: specifically, there have been 98 in the Henares Corridor, 78 in Madrid, and 16 in the Northwest Urban area. In the rest of Spain, highlights include 38 exceedances in Puertollano, 14 in the metropolitan area of Seville, 6 in Vic, and 6 in Penedès-Garraf.
A decisive factor has been a very warm and humid summer, especially in July and August, with two heatwaves that have contributed to the increase in ozone levels, particularly in the central and southern regions of the Iberian Peninsula. However, the impact has been less in the Cantabrian region, the Mediterranean, and the Canary Islands.
12% of the population affected according to current regulations
The report assesses the situation, also taking into account the new limit level or target value approved by the European Union, which must be achieved before 2030.
According to this threshold (referring to an evaluation over three consecutive years), the air polluted by ozone in the last triennium has affected nearly 9 million people, which represents 18% of its population. In other words, one out of every six Spanish individuals would have breathed in 2024 air that would fail to meet the new legal standard set by the European Union.
On the other hand, if we consider the objective value established by the current regulations, then the population that has breathed air with more ozone than allowed is reduced to 6 million people, 12% of the total. Globally, the situation affects the Community of Madrid, the Guadalajara metropolitan area, the Tiétar and Alberche Valley in Ávila, the Vic plain and the Catalan Pre-Pyrenees, and Villanueva del Arzobispo (Jaén).
The Mayor of Madrid, José Luis Martínez-Almeida, provides information about the air quality data in Madrid for the year 2022
96% of Spaniards affected, according to the WHO.
If we consider the value recommended by the World Health Organization (WHO), stricter than the legal target and more in line with proper health protection, ozone-polluted air has affected 46 million people in the Spanish State in 2024, 96% of its population. That is, almost the entire Spanish population has breathed air in 2024 with more ozone than recommended by the WHO.
The frequency of exceeding legal standards and WHO regulations has been lower than in the previous two years, with decreases of 34% and 23% respectively compared to the average recorded during the period 2012-2019 across the country.
However, 2024 has been the third year with the most exceedances of the information threshold since 2010.
A high toll in deaths
Air pollution from tropospheric ozone is a serious issue, as stated by the European Environment Agency (EEA), causing between 2,500 and 10,000 deaths every year in Spain (according to the estimation method, far exceeding traffic accidents).
“We are particularly concerned when the threshold values are exceeded, as they indicate that there is a structural problem and chronic health issues may arise,” Ceballos says.
During the summer of 2024 (May to September), the Carlos III Health Institute has identified 2,200 deaths attributable to high temperatures and increased exposure to pollutants such as ozone, lower than those recorded in 2022 and 2023 but above estimates from previous years.
“The report states that the exceeding of the legal target and the value recommended by the WHO has been systematically recurring in recent years, although with fluctuations depending on the year and territory considered.”
Ozone is a very complex pollutant that does not have a direct human source, but is formed by the combination of various precursor pollutants emitted by transportation (especially diesel vehicles), thermal power plants, certain industrial activities, or intensive livestock farming. Therefore, it is a typical pollutant in spring and summer.
Whose fault is it?
Scant development of low-emission zones
The report deems it necessary to reduce the exposure of the most sensitive population groups to this pollutant (children, the elderly, individuals with chronic cardiorespiratory diseases, and pregnant women), disseminating clear and understandable information during episodes of high pollution through educational, healthcare, social assistance, or sports centers, among other channels.
The main courses of action to address the issue include reducing motorized traffic in cities or promoting public and electric transportation, as well as pedestrian and cyclist access, along with ecological conversion (energy efficiency, renewable sources, reduction of marine pollution, limiting air traffic, etc.)
However, two years have passed since the deadline set by the Climate Change Law for all municipalities with more than 50,000 inhabitants to establish low emission zones (to improve urban air quality), and almost all cities have failed to comply with this legal obligation. Additionally, the majority of local and regional administrations lack action protocols for ozone pollution episodes, despite the legal deadline to implement them expiring almost two years ago.
