African dust clouds over the Caribbean spark health concerns

Dust travels across the Atlantic Ocean in late July (NASA)

Wednesday, August 28, 2013, 11:11 AM -

Scientists say it's nothing new. Tiny dust particles kicked up by African sandstorms blow thousands of kilometres across the Atlantic each summer. 

This year however, some experts say the clouds have grown, covering the eastern Caribbean islands and Mexico's Yucatan Peninsula in recent weeks. It's even been detected as far away as Texas and Wyoming. 

The dust typically limits visibility over the Caribbean, produces poor air quality and can even hinder the formation of hurricanes. 

Earlier this month, NOAA's satellites detected a plume of dust moving off the coast of Africa, playing a role in the Atlantic hurricane season.

"Many tropical systems begin as “waves” or areas of thunderstorms off the coast of Africa that then traverse the Atlantic Ocean toward North America," says Dayna Vettese, a meteorologist at The Weather Network. "What we have been seeing is that very dry air (dust and sand) being forced off the coast of Africa into the Atlantic Ocean. This type of dry air inhibits the formation of tropical waves which leads to the reason why we have no suspect areas in the region." 

NASA has been sending unmanned drones into tropical storms to study the phenomenon. Experts are also calling for more study to help understand the potential health impact the dust is having as well. 

So far this year, the dust prompted two health alerts in Puerto Rico for asthma and allergy sufferers. A lower level warning was also issued in the Dominican Republic.

Airborne particulate matter is connected to respiratory disease worldwide, but scientists say the specific impact on health is not yet known. 

"It has been extremely difficult to link specific particle composition to health effects,'' said Joseph M. Prospero, lead author of apaper on the dust to be published in September by the bulletin of the American Meteorological Society.

Human activity has changed the composition of the clouds over the years and scientists say they can contain trace amounts of things like metals, microorganisms, bacteria, spores, pesticides and fecal matter. 

With files from The Associated Press