Major Saharan Dust Outbreak Ongoing, Higher Concentrations Forecast Over Next 48 Hours

Concentrations of Saharan Dust are forecast to increase across the region, even with already significant concentrations of Saharan Dust present across T&T. Peak concentrations are forecast over the next 48 hours with air quality and visibility significantly reduced.

This Saharan Dust outbreak is forecast to rival 2020’s “Godzilla” dust plume which brought air quality across T&T to hazardous due to Saharan Dust for the first time in history.

Tropical Wave 06 is forecast to move across the region on Thursday with any showers that develop, bringing down notable concentrations of dust onto the surface. Showers will be limited due to a very dry atmosphere.

The Environmental Management Agency (EMA) air quality monitoring stations are recording AQI values at levels that are moderate to unhealthy for sensitive groups in Trinidad and Tobago. 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.

Visibility across Trinidad is approximately 5 kilometers, while across Tobago and other Southern Windward islands at 10 kilometers.

The Saharan Dust Forecast

Peak concentrations are forecast to begin overnight tonight into Thursday and continue through mid-Saturday. Air quality levels are forecast to dip to unhealthy and, at times, very unhealthy levels across T&T and the Southern Windward Islands. Visibility will be reduced below 5-7 kilometers across the country.

Concentrations are forecast to slowly decrease into the start of the new week, with the passage of Tropical Wave 07 moving across the region on Monday into Tuesday. Still, moderate to high concentrations are forecast to remain across T&T with air quality levels near moderate.

Another surge will follow the passage of Tropical Wave 07 on Wednesday into Thursday, with air quality levels remaining near moderate, at times reduced to unhealthy for sensitive groups. Moderate to high concentrations will remain across T&T until June 19th, 2021.

00Z 9th June 2021, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust.

What does this mean for you?

For the general population, with a major Saharan Dust outbreak ongoing, there may be increased aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; increased respiratory effects in the general population. Everyone may begin to experience health effects buy members of sensitive groups may experience more serious health effects.

Through Saturday 12th June 2021, everyone may experience more serious health effects. There will be a significant aggravation of heart or lung disease & premature mortality in persons with cardiopulmonary disease and the elderly. A significant increase in respiratory effects in general population is expected.

We’re in a period where the ITCZ and tropical waves 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 the strength of the wave 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 to occur in April and continue through November.

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