Texas - If you're coughing and sneezing more than usual this week, you can blame it on the Sahara Desert.

An enormous cloud of Saharan dust stretching from the African coast to the Gulf of Mexico will begin moving through the Dallas-Fort Worth area today and could blanket much of North Texas off and on through next week, said Bryan Lambeth, senior meteorologist at the Texas Commission on Environmental Quality.

A wave of dust

The dust is a regular problem this time each year when storms in North Africa lift Saharan sand and dust into the upper atmosphere, where it is carried thousands of miles across the Atlantic Ocean on the same tropical wave that blows hurricanes into the Caribbean and Gulf.

Health concerns

The chief health concern is particulate matter - microscopic dust so small it can sidestep the lungs' natural defenses. Commonly found in automobile exhaust and smoke, these tiny particles are to blame for respiratory diseases, cardiovascular problems and thousands of premature deaths each year nationwide.

State regulators project air quality in Dallas-Fort Worth to be moderate through the weekend, meaning the dust cloud could aggravate the conditions of those with respiratory problems such as asthma, but it should not pose much of a risk to an otherwise healthy person.

Still, Lambeth cautions the particles will contain allergens. "Those sensitive to allergens in dust may notice problems," he said.

A closer look

Every year, tons of sand and dust from the Sahara Desert in North Africa are blown thousands of miles across the Atlantic into North and South America.

The microscopic particles can contribute to health problems.

Most people only notice the dust clouds when they shroud the sunset in a yellowish haze.

Weather impact

The clouds have a beneficial effect: They help prevent hurricanes. The clouds inject dry air into the atmosphere, dampening tropical storm development.

They also block sunlight, cooling the ocean and limiting storm formation.

Rain could help dissipate the dust cloud. But Eric Martello, a meteorologist with the National Weather Service in Fort Worth, said, "We're really not expecting anything in the way of rain in the short term."