Mild to moderate concentrations of Saharan Dust are forecast to remain across Trinidad and Tobago this week, with additional surges forecast over the next 7 to 10 days, reducing air quality and visibility.
What you need to know
— Saharan Dust Surges: A mild to moderate concentration surge of Saharan Dust is present across Trinidad and Tobago, with dust levels remaining elevated through the week. Concentrations are set to increase by Thursday, May 5th, 2023, with another higher concentration surge by Sunday, May 7th, 2023.
— Impacts: Through the next seven to ten days, air quality levels across Trinidad and Tobago are forecast to remain between good and moderate, occasionally dipping to levels that are unhealthy for sensitive groups during high-traffic periods, in the vicinity of bushfires and between May 7th and 10th, 2023.
— What Should You Do: Sensitive groups may need to take the necessary precautions, particularly during high-traffic periods and in the vicinity of bushfires.
Current AQI Levels Across T&T
Based on information from official air quality monitoring stations from the Environmental Management Agency (EMA), San Fernando and Point Lisas are reporting moderate air quality levels, while at Arima, both stations are reporting good air quality levels based on Ozone levels. The station located at Signal Hill, Tobago is not reporting data.
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 remained unaffected by Saharan Dust and smoke at the A.N.R. Robinson International Airport at Crown Point, Tobago, and the Piarco International Airport, Trinidad.
Saharan Dust Forecast
Ongoing Surge
Saharan Dust levels are set to remain at elevated levels through the forecast period, with two surges set to move across the country over the next week. The first is set to arrive on Thursday, May 4th, 2023, with mild to moderate concentrations. By Sunday, May 7th, 2023, a moderate concentration surge is forecast to arrive, with dust levels at higher concentrations through overnight Tuesday, May 9th, 2023. Some improvement is forecast by Thursday, May 11th, 2023, with another moderate surge arriving by Friday, May 12th, 2023.
Through the next seven to ten days, air quality levels across Trinidad and Tobago are forecast to remain between good and moderate, occasionally dipping to levels that are unhealthy for sensitive groups during high-traffic periods, in the vicinity of bushfires and between May 7th and 10th, 2023.
What does this mean for you?
The air quality is forecast to be lowered primarily during high traffic periods, particularly between 6:00 AM and 9:00 AM and again from 3:00 PM through 6:30 PM, as well as during times of blowing smoke and dust from bushfires.
The sources of Saharan Dust across the Atlantic are in a transitionary phase at the moment.
Generally, the surges of dust from the end of November through April 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.
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. 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 associated with West African thunderstorms driving dust into the upper atmosphere from April through November – which is now beginning to take place.
