A surge of Saharan Dust moved across Trinidad, Tobago, and the Lesser Antilles over the last week, with concentrations decreasing into the weekend. While higher concentrations are forecast to remain north of Trinidad and Tobago, another dust surge is forecast to reach the region by Thursday, October 20th, 2022.
What you need to know
— Saharan Dust Surges: A mild and brief surge of Saharan Dust is forecast to move across the Lesser Antilles Monday night, October 18th, 2022, into Tuesday, October 19th, 2022. A moderate concentration surge is forecast to move across the region from Thursday, October 20th, 2022, and linger into Saturday, October 22nd, 2022.
— Impacts: Through the next seven to ten days, air quality levels across Trinidad and Tobago will fluctuate between good and moderate levels.
— What Should You Do: Sensitive groups may need to take the necessary precautions, particularly during high-traffic periods. The general population will remain unaffected.
Current AQI Levels Across T&T
The Environmental Management Agency (EMA) air quality monitoring stations at Port of Spain and Point Lisas have recorded good to moderate air quality levels over the last 24 hours. The stations at Signal Hill and San Fernando have not reported data in the last 24 hours.
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 dipped to seven kilometers at the A.N.R. Robinson International Airport at Crown Point, Tobago but remained at or above ten kilometers at the Piarco International Airport, outside of shower and thunderstorm activity.
Saharan Dust Forecast
Surge #1: Late Monday, October 17th, 2022
A brief and low-concentration surge of dust is forecast to arrive across Trinidad, Tobago, and the remainder of the Lesser Antilles from late Monday, October 17th, 2022. Improvement is forecast by late Tuesday, October 18th, 2022.
Air quality levels will fluctuate between good and moderate. Horizontal visibility is forecast to remain unaffected.
Surge #2: Thursday, October 20th, 2022
A moderate-concentration surge of dust is forecast across Trinidad, Tobago, and the remainder of the Lesser Antilles from Thursday, October 20th, 2022. Concentrations are forecast to gradually decrease into the next weekend
Air quality levels will fluctuate between good and moderate. Horizontal visibility may dip as low as 7 kilometers outside of shower and thunderstorm activity.
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.
We’re in a period where the Intertropical Convergence Zone and tropical waves and occasional tropical cyclones may shield Trinidad and Tobago from the Saharan Dust events. While Tropical Waves play a notable role 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.
