African dust storms traveling far

A press release from the Rosenstiel School of Marine and Atmospheric Science: You might find it hard to believe that dust clouds from the African Sahara can travel thousands of miles across the Atlantic Ocean, but it does every year and in large quantities. In a recent study, Joseph Prospero, professor emeritus at the University of Miami Rosenstiel School of Marine and Atmospheric Science and collaborators at the University of Houston and Arizona State University found that the average air concentrations of inhalable particles more than doubled during a major Saharan dust intrusion in Houston, Texas.

The researchers were able to distinguish between particles transported across the Atlantic and those from local sources in the Houston region. In this way they established the “fingerprint” of the African dust. To their knowledge, this is the first study that isolates, differentiates, and quantifies the air contaminants in the US during the incursion of African dust. There is a concern that the fine airborne dust particles could be a health problem for asthmatics and people with respiratory problems.

Current EPA air quality standards are based on the total amount of particles that are in the air,” Prospero says. “Our study will contribute to our ability to discriminate and identify the dominant components in the air during long-range transport events,” he says. “Our hope is that our work is instrumental in assisting regulatory agencies respond to health and environmental issues linked to African dust.”

The findings published in the journal of Environmental Science and Technology can also serve to address African dust intrusion in other affected regions of the world. For instance, the Caribbean Basin receives enormous quantities of African dust every year.  In addition to its impact on air quality, an important factor for the Caribbean basin is the potential effect of Saharan air outbreaks on hurricane activity.       

African dust storms are associated with hurricane season because the meteorological situations that are involved with generating tropical cyclones are also associated with the generation and transport of dust,” Prospero says. “The dust emerges from the coast of Africa in a hot, dry, elevated layer – the Saharan Air Layer (SAL) following behind Easterly Waves from which tropical cyclones sometimes develop,” he says. “The SAL interacts with the waves in complex way, so that the relationship is not entirely clear. It is the subject of much ongoing research.”...

African dust storm, image by NASA