Peak Saharan Dust Concentrations Ongoing

Saharan dust concentrations have peaked across T&T over the last 12 hours, with concentrations gradually diminishing as we progress through the week.

Overnight, air quality across northern Trinidad dripped to levels that were unhealthy for sensitive groups and visibility dropped to 7 kilometers at Piarco. By daybreak, air quality improved to moderate levels and is expected to remain there through the next day or so.

Air quality across the Eastern Caribbean as of 2:00 PM Monday 23rd November 2020
Air quality across the Eastern Caribbean as of 2:00 PM Monday 23rd November 2020

Across the country, air quality is at moderate levels presently with visibility at 10 kilometers as of 2:00 PM Monday 23rd November 2020.

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

Environmental Management Agency Air Quality Index Monitoring System as of 2:00 PM Monday 23rd November 2020.
Environmental Management Agency Air Quality Index Monitoring System as of 2:00 PM Monday 23rd November 2020.

The Saharan Dust Forecast

Adding onto the previous forecast, higher concentrations still remain north of T&T, with peak dust concentrations present across Northern Trinidad and Tobago on Monday. Saharan Dust concentrations are still forecast to diminish by Wednesday 25th November 2020.

Based on the latest dust modeling, air quality across Trinidad and Tobago is forecast to remain at moderate levels through Wednesday, at good levels through the latter half of the week, then good to moderate levels by the weekend into next week due to another mild surge of dust.

02Z Sunday 22nd November 2020, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. (Weathermodels)
02Z Sunday 22nd November 2020, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. (Weathermodels)

What does this mean for you?

For the general population, with mild to moderate Saharan dust concentrations forecast, little to no impacts are forecast beyond reduced visibility. For sensitive groups, such as children, the elderly, and persons who suffer from respiratory ailments and allergies, you may need to avoid prolonged exertion outdoors.

We’re in a period where the ITCZ, tropical waves, and occasional tropical cyclones 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 frequent 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.

Larger, more concentrated plumes of Saharan dust begin to occur in April and continue through November.

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