A plume of dust is affecting air quality in Florida and may reach other Southern states soon. Here’s what we know about the potential health effects.
A plume of dust that has traveled across the Atlantic Ocean from the Sahara was affecting air quality in Florida on Thursday and may reach other Southern states by the weekend.
Such events occur in the Caribbean and the Gulf Coast region several times a year, and scientists are studying how climate change may affect their frequency and intensity.
Here is what research shows about the health effects of Saharan dust exposure, and how people can protect themselves.
What is in the dust plume?
Dust plumes like this one originate in deserts, in this case, the Sahara. The dust is composed mainly of minerals found in desert sand, including silicates such as quartz.
But as they travel, plumes can pick up other pollutants, as well as bacteria, viruses and fungi. Reactions among the pollutants, and between those pollutants and sunlight, can produce additional chemicals as well.
What are the effects of exposure?
What makes Saharan dust dangerous is that its particles are extremely small, which means they can be inhaled deep into the lungs, irritating and damaging them.
From the lungs, fine particulate matter like this can enter the bloodstream, causing cardiovascular inflammation. For some people, it can also cause allergic reactions.
A study published in 2017 by researchers in Athens found that on days with high dust concentrations, there were significantly more emergency room visits for respiratory infections, exacerbations of asthma and exacerbations of chronic obstructive pulmonary disease. Another study, published in 2020 by researchers at the University of Colorado School of Medicine and the Environmental Protection Agency, found an increase in intensive-care admissions on such days.
Exposure can also lead to elevated blood pressure and irregular heart rhythms, said Dr. Stefania Papatheodorou, an associate professor of epidemiology at the Rutgers School of Public Health, who was the lead author of a recent review of existing research on Saharan dust. Researchers have also found an association between exposure and death from heart or lung disease.
Long-term exposure may increase the risk of developing lung diseases, in addition to exacerbating existing ones, according to Dr. Papatheodorou and research including a 2018 study. It may also be linked to preterm birth, and to attention and memory deficits in children. But more research is needed to confirm the long-term effects, Dr. Papatheodorou said.
Who is most vulnerable?
Saharan dust poses the greatest threat to children, older people and people with underlying lung or heart conditions.
For people with conditions like asthma or C.O.P.D., exposure “could easily set off a flare” of symptoms such as difficulty breathing, requiring urgent medical attention, said Dr. Panagis Galiatsatos, a pulmonary physician at the Johns Hopkins School of Medicine and a spokesman for the American Lung Association. And cardiovascular inflammation increases the risk of heart attack, especially in people who already have risk factors.
But that doesn’t mean adults without underlying conditions can safely ignore the dust.
“Your lungs are still going to be irritated,” Dr. Galiatsatos said. “These are volatile chemicals that you’re breathing in, that your lungs just don’t want.”
Healthy people are not as susceptible to the most serious threats, but they may still experience symptoms such as coughing, wheezing, chest tightness and headaches.
How can you protect yourself?
Dr. Galiatsatos recommended staying indoors as much as possible during a dust event, especially if you have an underlying condition.
If you do go out, it’s better to do so early or late in the day, he said, because chemical reactions between dust and sunlight can intensify the dust’s effects.
Depending on how well insulated your home is, dust may affect air quality indoors as well. A HEPA air purifier can help, the Caribbean Public Health Agency has said. If you don’t have one, you might consider a D.I.Y. alternative called a Corsi-Rosenthal box.
For people who cannot stay indoors, a high-quality mask such as an N95 provides significant protection. Surgical and cloth masks do not filter dust well, Dr. Papatheodorou said.
Staying well hydrated also helps because it keeps the airways lubricated, Dr. Galiatsatos said, and that lubrication can capture dust particles before they enter the lungs.
Finally, it is important to change your clothing after you get home. Dust particles will cling to the clothes you wore outside, and if you keep them on indoors, you will continue to be exposed.
How can you tell if precautions are needed?
Often, the pollution will be apparent to the naked eye as a fog or a hazy sky. But the Air Quality Index, or A.Q.I., is also a good indicator, even in the absence of visible haze. That data is available on weather apps, as well as AirNow.gov.
The A.Q.I. does have limitations when it comes to dust events, because the index was designed mainly to measure pollutants from combustion — cars, factories and wildfires, for example — and doesn’t capture all of the pollutants in Saharan dust.
It will still provide a decent measure of air quality during a dust event, but Dr. Galiatsatos recommended mentally adding 10 to the A.Q.I. number, and behaving accordingly.
