Study confirms record Sahara dust event hit Spain from 2020 to 2022

Cabo de Gata, Almeria during the dust event on March 15, 2022 | Eva de Mas (EEZA-CSIC). Credit: Eva De Mas (EEZA-CSIC)
A study by the Spanish National Research Council (CSIC), an agency belonging to Spain’s Ministry of Science, Innovation and Universities, shows that during 2020 the most intense Saharan dust event ever recorded in Spain and Portugal’s air quality monitoring network. It was concluded that this occurred. And in 2022.
The study, published in Atmospheric Chemistry and Physics, confirms the record-breaking nature of the dust storms that occurred in the Canary Islands in February 2020 and in mainland Spain and mainland Portugal in March 2022, turning the skies orange. It was associated with significantly higher dust concentrations. .
Dust concentrations were so high that air quality monitors were unable to measure high concentrations of respirable PM10 particles, said Sergio Rodriguez, CSIC researcher at the Institute of Natural Products and Agrobiology in Tenerife (Canary Islands). and Jessica López Darias, Data Reconstruction Techniques. The concentration of respirable PM10 and PM2.5 particles, i.e. particles with a diameter of less than 10 microns and 2.5 microns, respectively, is an important record of the air quality network in European Union standards.
Since early February 2020, two CSIC scientists have reported that during the Saharan dust event, the PM10 monitors of the Canary Islands air quality network were “saturated,” meaning that “PM10 concentrations increased to reach 1,000 µg/m3. ” I observed that. This is the highest concentration that many commercially available instruments can measure and is a much higher PM10 concentration than the 20-30 μg/m3 of PM10 that characterizes the Canary Islands under dust-free conditions,” explains Rodríguez. I did.
During these events, PM10 monitors were saturated while PM2.5 monitors showed high but fluctuating concentrations. This allowed us to develop a new data reconstruction method that can be validated with a small number of instruments capable of measuring over 1,000 µg/m3. This reconstruction method was applied to dust events that affected the Canary Islands in February 2020, February 2021, January and February 2022, and the Iberian Peninsula in mid-March 2022.
The reconstructed data shows that “during these dust events, hourly average concentrations of PM10 respirable particles reached values close to 5,000 micrograms per cubic meter in Tenerife and Almeria, and as low as 5,000 micrograms per cubic meter in Gran Canaria. “over 5,250 micrograms,” Jessica Lopez said.
historical record
The researchers analyzed data from 2000 to 2022 from 341 air quality monitoring stations in Spain and Portugal, reproducing 1,690 hourly averages of PM10 concentrations from 55 stations. I configured it. Then, the 24-h average PM10 concentration was calculated. This is because this is the parameter used by the World Health Organization, which recommends that the population not be exposed to concentrations above 45 μg/m3. The results show that PM10 concentrations increased significantly during the Sahara dust event in the period 2020–2022 compared to the Sahara dust event in the period 2000–2019.
The Canary Islands experienced severe dust events (2000-2019), with PM10 concentrations typically ranging from 200 to 400 µg/m3 (24-hour average). However, during the period 2020–2022, there were six extreme dust events with PM10 concentrations in the range of 600–1,840 µg/m3. The latter value was recorded in Gran Canaria.
During the dust event of 15-16 March 2022, when a large dust air mass from Algeria crossed the Iberian Peninsula from the southeast to the northwest, mainland Spain and mainland Portugal reached record PM10 concentrations.
“In mainland Spain and mainland Portugal, PM10 concentrations during Saharan dust events are typically less than 100 micrograms per cubic meter, but during the extreme dust event of March 15-16, 2022, 24-hour average PM10 concentrations were typical “In the Sahara the values were 1,500 to 3,100 in Almería, 800 to 950 in Salamanca, Ávila and Valladolid, 600 to 650 in central Portugal, and 440 to 480 in Orense and northern Portugal,” Rodriguez said. spoke.
These are the highest dust concentrations recorded by the Air Quality Network since measurements were standardized in the European Union in 2005. The researchers also analyzed previous data.
Meteorology and climate change
These extreme dust events are occurring in an unusual weather scenario characterized by an anticyclonic situation that deviates southward over the Iberian Peninsula and Western Europe and is blocked from the Canary Islands to the region of Cape Verde. Cyclones were regularly associated with the mid-latitude westerly circulation.
High pressure over the Iberian Peninsula and low pressure south of the Canary Islands – Cape Verde causes a meteorological dipole (clockwise above the high and counterclockwise within the low) with strong winds, resulting in large amounts of dust. Release and transport occur.
The study does not say whether these extreme dust events are caused by climate change. However, the researchers believe that all of these extreme dust events are characterized by features similar to atmospheric circulation anomalies, with a subtropical high moving to high latitudes, a widening tropical belt, and Rossby waves amplified in midlatitudes. It emphasizes that this occurred during a weather anomaly in the Northern Hemisphere. According to previous research, this is due to climate change.
The extreme dust event, which the study’s authors refer to as a “Dachs episode,” is an emerging weather phenomenon. In 2018, the Dakst incident affected the eastern Mediterranean. In June 2020, the so-called Godzilla incident affected the Caribbean and North America. Two duct events occurred in China in March 2021, and a new duct event occurred in Uzbekistan in November 2021, but all phenomena were caused by meteorological dipoles.
These dust events occur in the paradoxical context of reduced dust emissions in North Africa and Asia due to climate change-related reductions in wind speeds, which makes long-term predictions for these events making it extremely difficult.
Further information: Sergio Rodríguez et al., Extreme Saharan dust event expands northward in Atlantic Ocean and Europe, triggering record-breaking PM10 and PM2.5 episodes, Atmospheric Chemistry and Physics (2024). DOI: 10.5194/acp-24-12031-2024
Provided by the Spanish National Research Council
Source: Record-breaking Saharan dust event to hit Spain between 2020 and 2022, study confirms (October 29, 2024) https://phys.org/news/2024-10-saharan-events- Retrieved October 29, 2024 from spain.html
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