News / Science & Technology

Africa Kicks-up A Lot of Dust

NASA satellite captures image of giant dust cloud from Western Sahara on Sept. 14, 2013. Winds carry the dust to the United States, South America and the Caribbean. Credit: NASA
NASA satellite captures image of giant dust cloud from Western Sahara on Sept. 14, 2013. Winds carry the dust to the United States, South America and the Caribbean. Credit: NASA

Multimedia

Audio
Joe DeCapua
Bits and pieces of the African continent are falling on the United States and surrounding regions much of the year. Scientists say large amounts of African dust may be having major effects on the hurricane season, ocean organisms and human health.


African dust particles become airborne during storms and travel anywhere from 7,000 to 10,000 kilometers to reach the U.S.  Scientists can now distinguish between domestic dust particles and those from Africa.

Joseph Prospero studies dust. He’s professor emeritus at the University of Miami Rosenstiel School of Marine and Atmospheric Sciences. Prospero said dust is important for a number of reasons, including its effect on climate.

“The very fact that you can see dust in the atmosphere means that the dust is interacting with solar radiation, scatters and absorbs solar radiation. So, anything that affects the distribution of solar radiation on the Earth’s surface – whether it’s at the surface itself or in the atmosphere – will affect climate,” he said.

Dust will also reduce the amount of sunlight reaching the ocean. That’s a big deal, especially for those who live in the usual paths of hurricanes.

“The surface oceans will be somewhat cooler than they would be in the absence of dust. This is something of considerable interest because this region of the Atlantic is where we see tropical cyclones and hurricanes develop. And the fact that we have so much dust means you have cooler sea surface temperatures and the cooler sear surface temperatures mean less water vapor getting into the atmosphere. And water vapor is an essential component that drives tropical cyclones and hurricanes,” he said.

So, that’s a benefit of African dust for those who fear their houses will be damaged by such storms.

Prospero said, “Until recently – the last few weeks – this year has been unusually dusty and we’ve had remarkably few tropical cyclones and hurricanes.

Dust also affects climate by depositing in the ocean.

“Dust carries with it a lot of elements and one that’s [of] particular interest is iron, which in many regions, ocean regions, is a limiting nutrient. Phytoplankton – marine organisms – need iron in order to photosynthesize. It’s an essential micronutrient. Therefore, if there’s not enough iron, then you have less biological activity, which, of course, affects the carbon cycle. Anything that affects the carbon cycle will affect climate by modulating the amount of CO2 in the atmosphere,” he said.

Now, lest you think that African dust only has benefits, think again. It also ends up in people’s lungs – a problem for those with asthma, for example.

“[In] one of our studies we’ve shown that in the Caribbean region the concentrations of dust are so high that they often exceed the World Health Organization’s 24 hour standard for the concentration of particles,” said Prospero.

Recently, average concentrations of dust particles that could be inhaled more than doubled over Houston, Texas – all due to a major Saharan dust intrusion.

“With satellites we can see that that dust cloud extended from Central America – it was against the mountains of Central America – across all of Texas and up into northern Oklahoma. The satellite images lost the dust in a large area of cloud,” he said.

Prospero said there was a time when scientists did not pay much attention to atmospheric dust. That’s changed.

“When I first started this work in the mid-late 1960s, no one cared about dust and there were very few publications. And now, it’s phenomenal. Every year, there are literally hundreds and hundreds of publications about dust. I mean not only African dust, I mean there’s Asian dust. The other huge area of dust activity is in Asia.  Dust is ubiquitous and there hasn’t been much attention paid to it.”

Prospero -- and colleagues at the University of Houston and the Arizona State University -- published their findings in the journal of Environmental Science and Technology. But there’s much they don’t know because the interaction of dust with the atmosphere is very complex and not well understood.

For example, North Africa is expected to get drier and produce more dust. But computer models don’t agree on what that means in the long-term for climate and human health.

In case you’re wondering, Africa is not expected to blow away. Prospero says it’ll just keep producing more and more dust.

You May Like

Philippines, Muslim Rebels Try to Salvage Peace Pact

Peace process faces major setback after botched military operation to find terrorists results in bloody gunbattle between government forces, Moro Islamic Liberation Front fighters More

Republicans Expect Long, Expensive Presidential Battle

Political strategist says eventual winner will be one who can put together strongest coalition of various conservative groups that make up Republican Party More

Video New Wheelchair Is Easier to Use, Increases Mobility

Engineers have come up with a lever-operated design that makes use of easily accessible bicycle technology More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Liberia's Almost Last Ebola Patient Grateful but Still Grievingi
X
Benno Muchler
March 26, 2015 3:41 PM
Beatrice Yardolo was to make history as Liberia’s last Ebola patient. Liberians recently started counting down 42 days, the period that has to go by without a single new infection until the World Health Organization can declare a country Ebola-free. That countdown stopped on March 20 when there was another new case of Ebola, making Yardolo’s story a reminder that Ebola is far from over. Benno Muchler reports from Monrovia.
Video

Video Liberia's Almost Last Ebola Patient Grateful but Still Grieving

Beatrice Yardolo was to make history as Liberia’s last Ebola patient. Liberians recently started counting down 42 days, the period that has to go by without a single new infection until the World Health Organization can declare a country Ebola-free. That countdown stopped on March 20 when there was another new case of Ebola, making Yardolo’s story a reminder that Ebola is far from over. Benno Muchler reports from Monrovia.
Video

Video Cambodian Land Grabs Threaten Traditional Communities

Indigenous communities in Cambodia's Ratanakiri province say the government’s economic land concession policy is taking away their land and traditional way of life, making many fear that their identity will soon be lost. Local authorities, though, have denied this is the case. VOA's Say Mony went to investigate and filed this report, narrated by Colin Lovett.
Video

Video US, South Korea Conduct Joint Military Exercises

The Eighth U.S. Army Division and the Eighth Republic of Korea Mechanized Infantry Division put on a well orchestrated show of force for the media this week during their joint military training exercises in South Korea. VOA’s Seoul correspondent Brian Padden was there and reports the soldiers were well disciplined both in conducting a complex live fire exercise and in staying on message with the press.
Video

Video Space Program Status Disappoints 'Last Man on the Moon'

One of the films that drew big crowds last week at the annual South by Southwest festival in Austin, Texas, tells the story of the last human being to stand on the moon, U.S. astronaut Eugene Cernan. It has been 42 years since Cernan returned from the moon and he laments that no one else has gone there since. VOA’s Greg Flakus reports.
Video

Video Young Filmmakers Shine Spotlight on Giving Back

A group of student filmmakers from across the United States joined President Barack Obama at the White House this month for the second annual White House Student Film Festival. Fifteen short films were officially selected from more than 1,500 entries by students aged 6 through 18. The filmmakers and their families then joined the president and a group of celebrities for a screening of their films. VOA’s Julie Taboh reports.
Video

Video VOA Exclusive: Interview with Afghan President Ashraf Ghani

Afghan President Ashraf Ghani, during his first visit as president to Washington, gave a one-on-one interview with VOA Afghan Service reporter Said Suleiman Ashna, about his request for a change in U.S. troop levels, the threat from the Islamic State, and repairing relations with the United States and Pakistan. The interview was held at Blair House, late Sunday, in Pashto.
Video

Video California Science Center Tells Story of Dead Sea Scrolls

The ancient manuscripts were uncovered in the mid-20th century, and they are still yielding clues about life and religious beliefs in ancient Israel. As VOA's Mike O'Sullivan reports, an exhibit in Los Angeles shows how modern science is bringing the history of these ancient documents to life.
Video

Video Angelina Jolie Takes Another Bold Step

Hollywood actress and filmmaker Angelina Jolie has revealed she had her ovaries and fallopian tubes removed to lower her odds of getting cancer. Doctors say the huge publicity over her decision will help raise awareness about the importance of cancer screening. VOA’s George Putic has more

All About America

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More