Next Wednesday, March 20th, marks the end of astronomical winter, a season in the Canary Islands characterized by being the warmest since records began in 1961 and marked by an acute lack of rainfall, leading to extremely arid conditions and a prevalent haze of suspended dust particles.
The Spanish Meteorological Agency (Aemet) has reported on this winter season, spanning from December 1st to February 29th, noting that out of these 90 days, only 12 were free from the effects of Saharan dust suspended in the atmosphere of the islands. David Suárez, the Aemet delegate in the Canary Islands, pointed out that “in 85% of the days during December, January, and February, haze was present,” a phenomenon he described as “exceptionally rare for the islands during these months.”
This season, Aemet Canarias documented up to six days of intense calima, defined as Saharan dust clouds reducing visibility to below ten kilometres, surpassing the average of four days from the period 1991 to 2022. Since the beginning of 2024, the islands have already faced 19 days under pre-alert conditions for haze.
The prevalent high atmospheric pressures around the Canary Islands have resulted in fewer cold fronts reaching the archipelago and the nearby African coast, reducing precipitation and facilitating several episodes of Saharan dust incursion over the recent months. These episodes led to elevated concentrations of PM10 particles (particles smaller than or equal to 10 microns in diameter).
The experts at Aemet’s Izaña Observatory, after two decades of observation, have noticed a shift in atmospheric conditions, reporting a lack of seasonal patterns and predicting more frequent winter and spring dust intrusions, further degrading air quality. There’s an observed increase in these episodes, prompting investigations into their causes.
David Suárez mentioned a significant decrease in haze since the 1980s but noted great variability, with more intense peaks becoming evident. He attributed these episodes to the prolonged drought in North Africa, which reduces soil moisture making dust more available for transport by strong winds, coupled with an eastward shift of the Azores anticyclone, explaining recent wintertime haze episodes in the Canary Islands.
As for climate change, Suárez conceded its probable connection to the increasing haze events, as rising temperatures and diminishing rainfall contribute to North Africa’s land desertification, affecting the availability of dust and altering predominant atmospheric patterns.
HAZE AGGRAVATES THE HEALTH OF PEOPLE WITH CHRONIC OR RESPIRATORY ILLNESSES
These haze episodes not only impact visibility but also significantly affect individuals with chronic or respiratory illnesses, leading to complications like bronchospasm, chest pain, and asthma attacks. The general population may experience respiratory issues, mucous membrane irritation, and other symptoms, particularly when engaging in outdoor activities or exercises.
Consequently, it’s advised to adopt self-protection measures during these episodes, such as ensuring access to medications, keeping doors and windows shut, and avoiding outdoor physical activities, especially for those with existing health issues.
Saharan dust, while detrimental to air quality and health, also plays a role as a natural fertiliser, enriching both soils and ocean waters, thereby influencing ecological processes like tuna migration in the Atlantic. However, despite its natural benefits, the increasing frequency and intensity of dust episodes, potentially exacerbated by global warming, pose ongoing challenges and health risks, necessitating continued monitoring and adaptation strategies.
