Following the passage of Tropical Wave 22, Saharan Dust concentrations are on the increase across Trinidad, Tobago, and the Eastern Caribbean, reducing air quality and visibility.
Across Trinidad and Tobago, air quality is at good levels with visibility above 10 kilometers as of 2:00 PM Sunday 12th July 2020. However, by nightfall through Wednesday, air quality and visibility may reach levels that are unhealthy for sensitive groups.
This moderate to severe surge of dust will peak on Tuesday. However, this surge of dust will not be as severe as what we experienced throughout June, with mainly sensitive groups affected.
This week is also forecast to be notably drier and less windy across Trinidad and Tobago. Hence, in localized areas, further reduced air quality will occur in areas with smoke, fires, and high vehicular traffic.
Both tropical waves in the East Atlantic are forecast to move across the area late next week into next weekend with marginal impacts to T&T at this time.
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.
The Saharan Dust Forecast
Based on the latest dust modeling, air quality across Trinidad and Tobago is forecast to reduce overnight, with peak concentrations on Tuesday. Dust concentrations will fluctuate over the next 10 days, with localized improvements in areas that experience brisk, isolated showers, mainly across Trinidad.
Note that higher concentrations are forecast to remain north of Trinidad and Tobago.
The good news is that following this surge of dust, Saharan Dust across the Atlantic Basin is forecast to be relatively subdued into the latter half of July.
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.