Heat and Dust Create ‘Toxic Atmosphere’ Over Greece’s Urban Centers

The air quality in Greece’s major cities is deteriorating under the combined pressure of heatwaves, dust, and stagnant weather, creating what scientists describe as a “toxic atmosphere” that traps pollutants over neighborhoods. This is no longer a distant threat but a daily reality for thousands of urban residents.

According to Dr. Andreas Flouris, a Professor of Physiology and director of the FAME Lab for Environmental Physiology at the University of Thessaly, the climate crisis is acting as a catalyst for air pollution. He explained that rising temperatures do not simply add new pollutants; they alter their chemical composition, making exhaust fumes more aggressive and resilient.

“The pollutants remain for more hours over the cities and become more burdensome for the human body,” Flouris noted.

A key factor in this process is ground-level ozone. While beneficial high in the atmosphere, at ground level it is a powerful irritant. Intense heat and increased sunlight accelerate the chemical reactions between exhaust gases, leading to higher concentrations of ozone compared to previous years.

At the same time, high temperatures amplify the effect of thermal inversion. This phenomenon occurs when a layer of warm air acts like a lid, trapping cooler, denser air and its pollutants close to the ground. Instead of dispersing, the contaminated air stagnates, forcing residents to repeatedly breathe the same toxic mixture.

Adding to the concern is the increasing frequency of dust transport from the Sahara. Dr. Flouris points out that desertification in North Africa, driven by rising temperatures, is increasing both the frequency and intensity of these dust events. This dust is far from harmless.

“During its transport, it binds bacteria, fungi, and heavy metals, arriving in Greek urban centers already ‘loaded’,” he said. These particles can penetrate deep into the respiratory systems of vulnerable populations, particularly children and the elderly.

The threat is compounded by extremely fine particulate matter, known as PM2.5, with a diameter of less than 2.5 micrometers. Due to their small size, these pollutants can bypass the lungs and enter the bloodstream, where they are linked to respiratory, cardiovascular, and neurological problems. Forest fires, which are becoming more common due to prolonged droughts, release vast quantities of these particles, which can travel hundreds of kilometers from the fire front.

The unique characteristics of Greek cities worsen the problem. Dr. Flouris highlights how geographical features, such as the mountains surrounding Athens, combine with the extensive use of concrete to restrict natural ventilation. The concrete absorbs and radiates heat, creating an “urban heat island” effect. Under these conditions, the toxic atmosphere becomes a near-permanent fixture.

The solution, according to Flouris, lies in redesigning urban spaces. “More green spaces, less dependence on cars, and materials that do not trap heat can reduce the burden,” he stated. He emphasized that air quality is the most direct indicator of public health, warning that if the climate crisis is not addressed at its root, clean air risks becoming “the scarcest commodity of the 21st century.”