How Worried Should We Be About the Saharan Dust Cloud’s Arrival?
2020 has brought us massive wildfires, the coronavirus pandemic, civil unrest and murder hornets. And now, for the planet’s next act? A giant Saharan dust cloud nicknamed "Godzilla" is traversing the globe. This unusually large phenomenon threatens to envelop the sky around us with dust and other particulate matter that can impact our health.
Every year a thick plume of dust forms from sand in the Sahara desert. The 2020 version of this event has turned out to be quite extreme, however — much like other events that have taken place this year — stretching 4,000 miles and alarming scientists. With everything frightening and tragic that’s been crammed into the first few months of this decade, many of us may be experiencing worry fatigue. But is this latest atmospheric abomination something that really deserves our concern?
The Saharan Air Layer’s Role
To understand the origins of the dust cloud, let’s start with the Saharan Air Layer (SAL). This is a particularly hot, dry and dusty layer of the atmosphere that originates from the Sahara Desert in North Africa. It contains sand, mineral dust, particulate matter and other detritus from the surface of the desert that gets kicked up and carried away in the air. As pressure systems move through the desert picking up sand and other particles, this layer grows in height, sometimes extending 20,000 feet into the sky.
During summer, the annual thunderstorm cycle over the Sahara disturbs the layer, kicking up more dust and sand from the desert’s surface in the process. Its growing height allows it to reach anticyclones. These are extremely large-scale wind patterns that circulate around regions of high atmospheric pressure — in this case, the Atlantic Ocean — and extend 15,000 feet above sea level. When the sand and dust reach the anticyclones, the pressure patterns carry the particulate matter westward across the ocean to North America.
Every year around this time, the dust cloud that the SAL forms during storms begins its journey across the Atlantic. The different pressure levels in the marine air push the particulate matter even farther up into our atmosphere, carrying it great distances. The dust cloud drops particulate matter along its route, creating a range of weather and health effects in the process.
Where Does the Saharan Dust Cloud Travel — and Is It Always Bad?
To best imagine how the dust cloud travels, visualize a large ring of air hovering several thousand feet above the North Atlantic Ocean with the equator as its lower boundary. It doesn’t touch down on land, and the winds within it travel in a clockwise motion but aren’t totally continuous. This pressure system is constantly moving and swirling along its semi-circular path, which exists above countries like Morocco, Mauritania, Spain’s Canary Islands, Puerto Rico, Cuba, various Caribbean islands and the United States’ Gulf Coast and eastern seaboard. This, too, is the path that the Saharan Dust Cloud follows as it’s propelled along by the pressure systems. The distance inward that it travels into the United States depends on its size. This summer, multiple plumes are expected, some of which are expected to travel as far west (or farther) as the Great Plains states.
As it moves, the cloud creates a number of environmental effects while passing over various areas, and the closer a country is to the Sahara Desert along the anticyclonic path, the more impacted by the cloud it usually is, too. The particles in the dust cloud are rich in iron and absorb incoming solar energy. This gives the plumes a cooling effect on the climate as they prevent short-wave radiation from hitting the earth and Atlantic Ocean. The dust cloud provides a source of nutrients for the ocean as it deposits particulate matter while it travels, and the phosphorus it carries helps enrich the Amazon rainforest. Another beneficial effect of the dust cloud is that it can suppress the formation of tropical storms and hurricanes, starving them of the moisture they use as fuel.
Unfortunately, while the dust cloud can help the environment (however temporarily), there are also negative impacts on human health that can result from the plumes. These can develop even when the dust clouds are small or typical. So what might 2020’s Saharan Dust Cloud bring?
2020's Godzilla-sized Dust Cloud
This year's Saharan Dust Cloud is potentially the largest ever on record, thus the Godzilla nickname, and experts have referred to this historic concentration of dust as the "largest in 50 years." It’s certain to be "the most extreme out of all dust-related weather events" this year as well, with aerosol-particle concentrations sitting at the highest levels researchers have ever measured. As a result, air-quality levels in areas where the plume travels are being reduced to hazardous levels. Fog-like hazes are forming, turning daylight into virtually night-like conditions. Visibility problems have been reported in many cities and are creating particularly difficult issues at airports, causing closures and grounding flights.
The size of this year's dust cloud — and the fact that multiple clouds are anticipated to hit — means the dust will travel farther and leave a bigger impact in its wake. The initial cloud has already reached Miami, New Orleans and Houston, turning skies an ominous shade of reddish brown and triggering poor air quality alerts for millions of people living in the Southern United States. The density of the dust has also prompted various health departments to issue warnings about the risks associated with the dangerous conditions that are developing and lingering.
How Does the Dust Cloud Impact Human and Environmental Health?
The pollution that the Saharan Dust Cloud produces is similar to other forms of air pollution. One pressing concern is the particulate matter that the cloud carries — and that people breathe in. The World Health Organization (WHO) states that environmental pollution from particulate matter is responsible for 1.4% of all deaths worldwide. While more studies are needed to demonstrate consistent results, the WHO has linked Saharan dust in particular to increased incidence of cardiovascular disease, respiratory illnesses such as asthma and some infectious diseases, along with elevated overall mortality.
Additionally, the dust cloud also carries with it pollution from human and animal waste, which can be damaging to human health when breathed in. Fungi, bacteria, mites, pollen and heavy metals such as mercury are all carried in the cloud and deposited along its path. All of these substances have impacts on human health.
The Saharan Dust Cloud also has the potential to contribute to harmful red algae blooms. The iron-rich nutrients in the cloud are believed to provide nitrogen for bacteria, allowing them to grow and thrive beyond their typical life cycle. Researchers are concerned that this year's dust cloud could spark red algae blooms along the coast of Florida, which would have harmful effects on the beaches and fishing industry in the area.
Should We Be Worried?
The size of this year's dust cloud is a concern. As a result of its size and the distance into the United States it’s expected to travel — coupled with the fact that the first cloud has already made its presence known by reducing air quality along the Gulf Coast — there’s little doubt that the arriving clouds will continue affecting air quality in some places. It’ll likely drop to hazardous or near-hazardous levels, driving negative effects on human and animal health in the process.
It’s also worrisome that these giant dust plumes are occurring at the same time as the COVID-19 pandemic rages on because areas with poorer air-quality levels have had a harder time containing the spread of the coronavirus. People who contract COVID-19 also tend to develop more severe symptoms if they live in areas with worse pollution, and even a small increase of particulate matter in the air can lead to a 15% increase in COVID-19 deaths. Researchers are also finding links between higher concentrations of particulate matter in the air and an increase in transmission of the virus, leading them to anticipate an increase in COVID-19 transmission and related deaths due to the plumes. Adding insult to injury is the fact that many COVID-19 symptoms mimic those that people may experience from breathing in Saharan dust.
If you live in the South, the Great Plains or even the Northeast, it’s essential to take precautions to protect yourself if you’re in an at-risk group, health-wise. Keep tabs on air quality levels when plumes are expected to arrive, and, if you use a rescue inhaler or another type of inhaler, make sure it’s full and that your prescription is up to date. It’s also important to know the symptoms that distinguish COVID-19 from dust irritation. Fever, muscle aches, gastrointestinal issues and loss of your sense of smell are much more likely to appear with COVID-19, whereas bronchial issues alone may be the result of irritation due to Saharan dust. In any case, it’s best to call your primary care provider for guidance if you’re experiencing any symptoms. Keep wearing a cloth face mask that covers your mouth and nose; in addition to potentially limiting the spread of the coronavirus, it may reduce the severity of any respiratory effects related to airborne particulate matter from the plumes.
While normally this annual phenomenon isn’t much to be too concerned about, the size of this year's event coupled with the COVID-19-related complications it can create means it’s best to take extra precautions to preserve your health. Stay informed with up-to-date weather information for your area, heed recommendations from local officials and continue to practice good health hygiene to safeguard your well-being.