Saharan dust plume could impact Florida sunsets. How can it affect our air quality?
Noticing a hazy look to the usually blue Florida skies? That could be dust carried from Africa's Sahara Desert, making the journey all the way to the Southeast states.
The first plume of Saharan dust to impact Florida this summer is headed our way this weekend, and it has the potential to influence air quality and affect our usual hues in the sky.
Forecast models from the National Hurricane Center show that dust could impact Florida and the entire Gulf Coast throughout the next week. In addition to poor air quality and less colorful sunsets, communities will continue to see hot temperatures and decreased rainfall.
What is the Sahara Air Layer?
According to NOAA, the Saharan Air Layer is a mass of very dry, dusty air that forms over the Sahara Desert. It typically forms during the late spring, summer, and early fall, moving over the tropical North Atlantic Ocean every three to five days.
It carries upwards of 66 million tons of dust annually over the ocean and the Americas.
What causes the Sahara Air Layer?
The outbreaks of Saharan dust can form when ripples in the lower-to-middle atmosphere, called tropical waves, track along the southern edge of the Sahara Desert and loft vast amounts of dust into the atmosphere.
As the SAL crosses the Atlantic, it usually occupies an over 2-mile-thick layer of the atmosphere with its base starting about 1 mile above the surface, the NOAA explains. The warmth, dryness, and strong winds associated with the layer have been shown to suppress tropical cyclone formation and intensification.
Is it common for the Saharan dust to cross the Atlantic on a regular basis?
Its activity usually ramps up in mid-June and peaks from late June to mid-August, with new outbreaks occurring every three to five days.
During the peak period, it is common for certain outbreaks to reach farther to the west—as far west as Florida, Central America, and even Texas—and cover extensive areas of the Atlantic (sometimes as large as the lower 48 United States).
How does the Saharan Air Layer influence weather and climate?
According to the National Weather Service, there are three characteristics of these "SAL" outbreaks that can affect tropical cyclones, tropical disturbances, and the general climatology of the Atlantic tropical atmosphere:
Extremely Dry Air: The Saharan Air Layer’s dry, dusty air has about 50% less moisture than the typical tropical atmosphere. This extremely dry air can weaken a tropical cyclone or tropical disturbance by promoting downdrafts around the storm.
African Easterly Jet: Strong winds in the Saharan Air Layer (25-55 mph or 10-25 meters per second) can substantially increase the vertical wind shear in and around the storm environment. This “mid-level jet” of enhanced winds, typically found at a height of 6,500-14,500 feet (2000-4500 meters), can cause tilting of the tropical cyclone vortex with height and can disrupt the storm’s internal heat engine.
Warm Temperatures: The Saharan Air Layer’s warmth acts to stabilize the atmosphere, which can suppress the formation of clouds. This stabilizing effect is produced when the Saharan Air Layer’s warm, buoyant air rides above relatively cooler, denser air. The Saharan Air Layer’s suspended mineral dust also absorbs sunlight, which helps maintain its warmth as it crosses the Atlantic Ocean.
Is the dust harmful to our air quality?
Saharan dust can be harmful to health. The Centers for Disease Control and Prevention says the Saharan dust worsens air quality and increases the levels of particulate matter in the air.
The air has about 50% less moisture than the typical atmosphere, which means the presence of the layer can be detrimental to cloud formation and thunderstorm activity.
What are the symptoms of Saharan dust?
The dust particles can be breathed in and enter your lungs and bloodstream, potentially triggering asthma attacks in people who have asthma and aggravating other respiratory conditions. Individuals with seasonal allergies can also be affected by the dust, encountering the typical symptoms of runny noses, sore throats, and itchy eyes.
Saharan dust has been linked to increased emergency department visits for:
Asthma
Chronic obstructive pulmonary disease (COPD)
Respiratory infections
How do I cope with the dust while it's here?
Dr. David Corry, professor of medicine in the section of immunology, allergy, and rheumatology at Baylor, offers the following tips to be safe while the dust is present:
Stay indoors as much as possible while the dust is in the air or wear a mask while outside
Run a HEPA filter indoors to purify the air, especially in the bedroom
Patients who use rescue or controlling medications for pulmonary conditions should have them on hand at all times and use them as prescribed
Seek professional medical advice at the first sign of difficulty breathing
For less severe symptoms, standard allergy medications such as antihistamines and steroid nasal sprays might be helpful
If you are experiencing a sore throat and runny nose and are unsure whether it is COVID, get tested
How can I check the air quality in my region?
This article originally appeared on Fort Myers News-Press: Sahara Air Layer 2023 headed toward Florida, will affect air quality
