As the Caribbean enters its annual Saharan dust season, regional meteorologists are sounding the alarm over a shifting pattern: significant dust outbreaks from the Sahara Desert are now arriving earlier than historical records indicate, and overall transatlantic dust transport has climbed to sustained high levels that threaten public health across the region.
Last week, thick plumes of Saharan dust already disrupted daily life across Barbados, hitting residents with pre-existing respiratory conditions particularly hard. For context, this pervasive weather phenomenon develops when dry mineral dust particles swept from the Sahara Desert are carried across the Atlantic by trade winds, lingering in the atmosphere over the Americas and Caribbean. The suspended particles drastically cut visibility, usually dropping it below 10 kilometers, and leave the sky looking milky, opaque, or faintly discolored.
Dr. Andrea Sealy, regional chair for the Americas at the World Meteorological Organisation’s Sand and Dust Storm Warning Advisory and Assessment System and a researcher based at the Caribbean Institute for Meteorology and Hydrology (CIMH), laid out the changing timeline of these events in an interview with Barbados Today on the sidelines of a medical education conference held in Bridgetown Sunday.
“What we’re seeing now, coming into April and early May, is far more dust than this region has historically seen this time of year,” Sealy explained. “In previous decades, the major significant dust outbreaks wouldn’t arrive until late May or even June. We’ve clearly observed a shift in the timing of severe events, and over the long term, the total volume of dust moving across the Atlantic has increased substantially.”
Continued satellite monitoring of West Africa’s coast confirms that large dust plumes are still regularly launching out over the Atlantic, feeding the ongoing hazy conditions across the eastern Caribbean. After a brief lull in dust levels earlier this week, concentrations are already climbing again. Sealy noted that while concentrations may dip temporarily in coming days, more significant dust outbreaks are likely through the coming weeks, marking 2024 as an unusually dusty season so far.
Beyond the shifting patterns of dust events, Sealy also acknowledged a key gap in public outreach: climate and weather advisories related to poor air quality do not always reach vulnerable communities effectively, though CIMH is working to improve communication channels. The institute coordinates closely with global and local health authorities to develop evidence-based guidance: when particulate concentrations cross safe thresholds set by the World Health Organization, officials advise against prolonged outdoor activity or strenuous exercise, particularly for sensitive groups. Still, Sealy emphasized that clinical health providers remain the best source of detailed personalized guidance for at-risk residents.
In addition to improving forecasting and public communication, CIMH is working to expand air quality monitoring infrastructure across the entire Caribbean region. At the center of this effort is a long-running dust monitoring station operated in partnership with the University of Miami at Ragged Point, on Barbados’ eastern coast. This year, the station marks 60 consecutive years of continuous dust measurements, earning it the distinction of being the oldest continuously operating dust observation site in the world.
This unparalleled decades-long dataset has turned Barbados into one of the most critical global hubs for Saharan dust research, and the data has already vastly improved CIMH’s forecasting abilities. Sealy reported that CIMH’s regional forecasting model accurately predicted last week’s major dust outbreak, and it consistently delivers reliable predictions of incoming events up to five days in advance, including estimates of the concentration of dust that can be expected when a plume arrives.
The expanded monitoring network will prioritize tracking harmful fine particulate matter, known as PM2.5 and PM10 — particles with diameters between 2.5 and 10 microns, roughly 30 times smaller than the average human hair, which can penetrate deep into the respiratory tract and cause severe health complications. To build out the network, CIMH is combining two types of sensors: high-precision reference-grade instruments that deliver the most accurate measurements for regulatory and research use, and more affordable consumer sensors from the PurpleAir network that can be deployed in far more locations.
While the lower-cost PurpleAir sensors are not as accurate as reference equipment, they are able to capture reliable trend data on air quality, and the public will be able to access real-time data from these sensors once the network is deployed. The end goal, Sealy explained, is to build a comprehensive monitoring system that meets the Caribbean’s growing need for accurate, accessible air quality measurement, monitoring, assessment and forecasting as dust events become more frequent and more intense.