A mild to moderate surge of Saharan Dust is forecast to move across Trinidad and Tobago from Thursday. The localized air quality will be further reduced by fires, blowing smoke into the upcoming weekend.
What you need to know
— Saharan Dust Surges: The ongoing mild dust surge is forecast to reduce by Tuesday, with another moderate surge arriving by Thursday, April 4th, 2024, during the afternoon and lingering into the weekend. Another surge is forecast by Tuesday, April 9th, 2024.
— Impacts: Air quality across T&T will range between good and moderate through Thursday. However, from Thursday, April 4th, through the remainder of the forecast period, air quality is forecast to reduce to moderate, occasionally reaching levels that are unhealthy for sensitive groups, with further localized reduction in air quality levels near fires through the forecast period
— What Should You Do: In times of unhealthy air quality, everyone should take the necessary precautions. Throughout the forecast period, unusually 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
The official air quality monitoring stations from the Environmental Management Agency (EMA) at Point Lisas, Mayaro, Arima, Beetham, and Scarborough are all reporting good levels, while at San Fernando, air quality is currently at Unhealthy levels.
Unofficial air quality monitoring stations at Longdenville, St. Augustine, and Woodbrook report mostly good air quality, with reduced levels at Longdenville.
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 the Piarco International Airport, Trinidad, outside of shower activity.
Saharan Dust Forecast
Sunday (Mar. 31st) through Thursday (Apr. 4th): The ongoing mild surge of Saharan Dust is forecast to decrease over the period, with little to no dust present from Tuesday afternoon through Thursday. With forecast rainfall set to decrease fire potential, air quality is forecast to vary between good and moderate levels during this period.
Thursday PM (Apr. 4th) through Sunday (Apr. 7th): Moderate Saharan Dust is forecast to be present through this period, with air quality generally moderate to occasionally unhealthy for sensitive groups in high traffic and near fires/blowing smoke. Note that pollen may also aggravate allergies and those sensitive to air quality changes.
Sunday (Apr. 7th) through Tuesday (Apr. 9th): Little to no Saharan Dust forecast to be present, with generally good to moderate air quality outside of near fires/blowing smoke.
Note that another Saharan Dust surge is forecast to arrive by Tuesday, April 9th, 2024, during the late morning through afternoon with longer range modelling showing this moderate surge lingering into the mid-month.
What does this mean for you?
In areas where blowing smoke occurs or near fires, air quality may dip to unhealthy levels (or below). Everyone may begin to experience health effects, and members of sensitive groups may experience more serious health effects.
From March 16th, air quality is forecast to reach generally moderate to unhealthy for sensitive groups. With elevated concentrations present and drier and breezier conditions bringing the risk of fires, air quality is still forecast to be reduced, with further reductions in localized areas of fires, blowing smoke and dust, and high traffic.
During this period, a ridge of high pressure stays over the central Sahara Desert, and the Intertropical Convergence Zone (ITCZ) remains over the Gulf of Guinea. The Harmattan wind accelerates when it blows across the mountain massifs of Northwest Africa. If its speed is high enough and it blows over dust source regions, it lifts the dust and disperses it.
The surges of dust during this time of year are due to the Harmattan, a season in the West African subcontinent that occurs between the end of November and the middle of March. During this season, a predominant northeasterly trade wind (dubbed the Harmattan Winds) blows from the Sahara Desert over Western Africa into the Gulf of Guinea.
Dust that makes it into the upper levels of the atmosphere can then get transported across the Atlantic Ocean and affect the Eastern Caribbean. These Saharan Dust outbreaks tend to be milder in the Eastern Caribbean than the dust outbreaks.
