While the Atlantic is experiencing its most significant Saharan Dust outbreak in the past two years, dust levels across Trinidad and Tobago are forecast to be lower than usual due to back-to-back tropical waves, keeping the Intertropical Convergence Zone across the area through the end of the week.
What you need to know
— Saharan Dust Surges: A mild to moderate surge of dust is forecast to move in, mainly across Tobago and northern Trinidad, on Thursday through Friday afternoon, with a moderate to high concentration of dust forecast to reach T&T from overnight July 20th, with mild to moderate dust levels across T&T through July 25th.
— Impacts: Air quality is forecast to remain good to moderate throughout the forecast period.
— What Should You Do: In times of unhealthy air quality, everyone should take the necessary precautions. Throughout the forecast period, sensitive groups are advised to take the necessary precautions, particularly during high traffic and in the vicinity of fires.
Current AQI Levels Across T&T
As of 3:00 PM Monday, July 15th, 2024, the official air quality monitoring stations from the Environmental Management Agency (EMA) at Arima, Point Lisas, Toco, and San Fernando all report good air quality, while at Signal Hill, Mayaro, and Beetham, no PM2.5 or PM10 data are currently being transmitted.
Unofficial air quality monitoring stations at Longdenville, St. Augustine, and Woodbrook are reporting good air quality.
These measurements are based on PM2.5 (particulates the size of 2.5 micrometers and smaller, usually associated with increases in Saharan Dust, vehicle exhaust, and smoke) and PM10 particulates.
Over the last 24 hours, visibility has remained at 10 kilometers at the A.N.R. Robinson International Airport at Crown Point, Tobago, and at the Piarco International Airport, Trinidad, outside of rainfall activity.
Saharan Dust Forecast For T&T
Across the remainder of the Atlantic, Saharan Dust levels are well above normal for this time of year, with the highest concentrations of Saharan Dust being recorded in the past two years.
The ongoing outbreak has at least temporarily turned off the tropics and has likely contributed to some cooling of Atlantic waters – especially closer to Africa. The dry, dust-laden air from the deserts of North Africa usually peaks in late June and July and is an anticipated part of the seasonal cycle. In 2023 Saharan dust was largely a no-show, with the lowest coverage of dust over the tropical Atlantic in at least 20 years (since satellites began measuring dust).
The passage of Tropical Waves 22 and 23 this week is forecast to keep the Intertropical Convergence Zone across T&T. All of these features will result in Saharan Dust staying north of T&T, at least through the end of the week.
Now through Friday (July 19th): Mild to no Saharan Dust due to the passage of Tropical Waves 22 and 23, keeping the ITCZ across T&T. Air quality levels remain mostly good.
Saturday (July 20th) through Thursday (July 25th): Generally moderate to occasionally high concentrations of Saharan Dust across both islands, with generally moderate air quality.
What does this mean for you?
Elevated concentrations of Saharan Dust periodically over the next seven to ten days are likely to bring air quality to moderate levels, chiefly affecting the most sensitive groups of the population. The general public is not required to take action.
We’re in a period where the Intertropical Convergence Zone, tropical waves, and occasional tropical cyclones may shield Trinidad and Tobago from the Saharan Dust events. While tropical waves are notable in moving dust across the Atlantic and the Eastern Caribbean, these periodic tropical waves also improve air quality.
The concentration of the dust that follows the wave depends on its strength as it moves off the West African Coast. This is because of stronger thunderstorms across Central Africa. As strong winds move downward and outward from these thunderstorms, the wind kicks up dust as it moves across parts of the Saharan Desert and transports it into the upper atmosphere. This “plume” of dust follows the axis of the wave as it progresses westward into the Atlantic.
Dust that makes it into the upper levels of the atmosphere can then get transported across the Atlantic Ocean. The plumes of dust eventually affect the Eastern Caribbean.
Larger, more concentrated plumes of Saharan dust begin in April and continue through November.
