Featured Research

from universities, journals, and other organizations

Unraveling the mystery of Saharan dust migration

Date:
August 22, 2013
Source:
University of Houston
Summary:
Scientists area studying the impact of Saharan dust on Houston's air quality, and how it might differ from other sources of pollution. The dust is carried across the Atlantic Ocean on trade winds most summers, and research has shown it can be differentiated from other sources of pollution.

Satellite pictures of Saharan dust clouds have been in the news all summer, but to Shankar Chellam, they have just raised more questions. How much impact did the Saharan dust have on Houston's air? Is it more toxic than our home-grown dust?

Chellam, a professor in the department of civil and environmental engineering at the University of Houston's Cullen College of Engineering, is searching for answers to those and other questions. Clouds of African dust often migrate across the Atlantic Ocean during summer months, affecting Houston's air quality from mid-June through mid-September. Chellam said it's especially prevalent in late August and early September.

The dust, whipped up by sandstorms in northwest Africa and carried by trade winds across the Atlantic Ocean, takes about 10 days to two weeks to reach the United States and, ultimately, Houston. Chellam said he collaborates on the project with Joseph Prospero, professor emeritus of marine and atmospheric chemistry at the University of Miami. Chellam became interested after he noticed "the most curious coincidence" as he was collecting data on industrial air pollution outside plants along the Houston Ship Channel in 2008. He began the project expecting that the plants would emit a constant amount of pollution, as measured from just beyond their property lines. But he discovered that on some days they emitted relatively little, while emissions were much higher on other days.

"What we quickly realized was that the impact of the refineries varied with time," he said. "We naively had gone into our research expecting that if we took three months of data, we would get an average." A five-day period in July and August 2008 showed a large variation. That coincided with an influx of Saharan dust, Chellam said. To determine the actual impact of the Saharan dust required scientific detective work. Chellam and his team determined the "fingerprint" of the African dust, allowing them to differentiate it from other types of pollutants in their samples: industrial dust, vehicle pollutants and smoke from wildfires, among other things. "There are millions of sources of pollution," he said.

His lab works with African dust collected in Barbados, before it has picked up other contaminants along the route to the United States. Still, he said, the metals in the dust are distinct. That finding allowed him to determine that a spike in pollution levels in the 2008 readings reflected the arrival of Saharan dust. A paper on those findings has been accepted for publication in in the journal Environmental Science and Technology. In addition to Prospero, his co-authors include Ayse Bozlaker, a post-doctoral researcher working with Chellam, and Matthew Fraser of Arizona State University. Work by other scientists has linked the dust migration with coral reef stresses and other environmental problems, but the impact on human health is less clear. Chellam, whose research does not extend into health impact, said he would expect it to affect people with asthma and other respiratory problems. "But clearly more research is needed," he said. "The composition of the dust is not the same" as other industrial and vehicle dust.

"And if the composition is different, the health impact may be different," he said.


Story Source:

The above story is based on materials provided by University of Houston. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ayse Bozlaker, Joseph Prospero, Matthew P. Fraser, Shankar Chellam. Quantifying the Contribution of Long-Range Saharan Dust Transport on Particulate Matter Concentrations in Houston, Texas, using Detailed Elemental Analysis. Environmental Science & Technology, 2013; 130819114111002 DOI: 10.1021/es4015663

Cite This Page:

University of Houston. "Unraveling the mystery of Saharan dust migration." ScienceDaily. ScienceDaily, 22 August 2013. <www.sciencedaily.com/releases/2013/08/130822122810.htm>.
University of Houston. (2013, August 22). Unraveling the mystery of Saharan dust migration. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2013/08/130822122810.htm
University of Houston. "Unraveling the mystery of Saharan dust migration." ScienceDaily. www.sciencedaily.com/releases/2013/08/130822122810.htm (accessed October 1, 2014).

Share This



More Earth & Climate News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: 12 More Bodies Found on Japan Volcano

Raw: 12 More Bodies Found on Japan Volcano

AP (Oct. 1, 2014) — A dozen more bodies were found Wednesday as Japanese rescuers resumed efforts to find survivors and retrieve bodies of those trapped by Mount Ontake's eruption. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Cultural Learning In Wild Chimps Observed For The First Time

Cultural Learning In Wild Chimps Observed For The First Time

Newsy (Oct. 1, 2014) — Cultural transmission — the passing of knowledge from one animal to another — has been caught on camera with chimps teaching other chimps. Video provided by Newsy
Powered by NewsLook.com
Raw: Trapped Scientist Rescued from Cave in Peru

Raw: Trapped Scientist Rescued from Cave in Peru

AP (Oct. 1, 2014) — A Spanish scientist, who spent 12 days trapped about 1300 feet underground in a cave in Peru's remote Amazon region, was rescued on Tuesday. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Media, Industry Groups React To Calif. Plastic Bag Ban

Media, Industry Groups React To Calif. Plastic Bag Ban

Newsy (Sep. 30, 2014) — California is the first state in the country to ban single-use plastic bags in grocery, liquor and convenience stores. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins