Brief Surge Of Saharan Dust Forecast To Arrive On Wednesday

A robust tropical wave, Tropical Wave 21, has quelled Saharan Dust concentrations across Trinidad, Tobago, and the Eastern Caribbean over the last day or so. As this wave moves west, a mild surge of Saharan Dust forecast to move across the region, reducing air quality to moderate levels by Wednesday afternoon across T&T.

Across Trinidad and Tobago, air quality is at good levels with visibility above 10 kilometers.

This mild surge of dust will peak initially on Wednesday evening, with a secondary peak on Tuesday. This surge of dust will not be as severe as what we experienced throughout June, with mainly sensitive groups affected.

Note that in localized areas, further reduced air quality will occur in areas with smoke, fires, and high vehicular traffic.

The Environmental Management Agency (EMA) air quality monitoring stations are presently recording AQI values at levels that are good 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.

Air Quality Index at Environmental Management Agency‘s (EMA) Air Quality Monitoring Stations Across Trinidad. Note these AQI values are to Trinidad and Tobago air quality standards.

The Saharan Dust Forecast

Based on the latest dust modeling, air quality across Trinidad and Tobago is forecast to reduce Wednesday morning across Tobago and Wednesday afternoon across Trinidad. Dust concentrations will fluctuate over the next 10 days, modulated by the ITCZ and tropical waves periodically improving air quality.

Note that higher concentrations are forecast to remain north of Trinidad and Tobago.

We may see a more significant surge on Monday into Tuesday, with air quality nearing levels unhealthy for sensitive groups.

Extended Air Quality Index based on the Saharan Dust Forecast For Trinidad and Tobago.
02Z July 7th, 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, 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. See the AQI levels versus the above Saharan Dust forecast for more details

We’re in a period where the ITCZ and tropical waves 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 aid in improving 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.

Sensitive groups such as persons with respiratory ailments, children, the elderly and cardiopulmonary disease should take the necessary precautions on days where dust concentrations degrade air quality to moderate and beyond, as there is more Saharan Dust forecast.

Saharan Dust Precautions
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