Lowered AQI Levels Continue, Another Surge of Saharan Dust Forecast by Weekend

Significant concentrations of Saharan Dust continues to move across the region, with air quality levels degraded across the entire Caribbean with another significant surge of Saharan Dust forecast to move across the region this weekend.

Across Trinidad, air quality is at levels unhealthy for sensitive groups with visibility near 6 kilometers. Across Tobago, air quality remains at unhealthy levels for the general population, with visibility near 8 kilometers.

Air quality index across Trinidad and Tobago as of 3:00 PM Tuesday 23rd June 2020
Air quality index across Trinidad and Tobago as of 3:00 PM Tuesday 23rd June 2020

This plume of dust is also affecting the Caribbean, with a number of islands reporting reduced visibility and air quality.

Air quality index across the Eastern Caribbean as of 3:00 PM Tuesday 23rd June 2020
Air quality index across the Eastern Caribbean as of 3:00 PM Tuesday 23rd June 2020

The peak of this ongoing Saharan Dust outbreak occurred on Sunday. Concentrations will slowly decrease through Thursday as a tropical wave moves through the Eastern Caribbean. However, another significant surge of Saharan Dust will move across the islands beginning late Friday.

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 unhealthy for sensitive groups to unhealthy 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.
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 continue slowly improving tonight through tomorrow. By Thursday, a tropical wave will move across the Eastern Caribbean, improving air quality and visibility across the region.

By late Friday, another severe surge of Saharan Dust will begin to move across the region, with air quality generally being reduced to unhealthy levels again across the region. Higher concentrations of dust will favor areas north of Tobago.

Extended 10-Day Air Quality Index based on the Saharan Dust Forecast For Trinidad and Tobago.

Note that on late Friday into Saturday, unhealthy to very unhealthy air quality (for the entire population) is possible, triggering health alerts for some islands as some of the highest concentrations will remain north of T&T.

Concentrations are forecast to remain elevated through the week, with the exceptions occurring on Thursday into early Friday and then again beginning next Tuesday.

00Z 23rd June 2020, CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. (Weathermodels)
00Z 23rd June 2020, CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. (Weathermodels)

Note that the ongoing plume of Saharan Dust is forecast to flow into the United States Gulf Coast and Central America later this week, with another round of dust moving across the Caribbean this weekend.

What does this mean for you?

On Friday into Saturday, health alerts are possible as everyone may experience more serious health effects. A significant increase in respiratory effects in the general population is expected. 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
Saharan Dust Precautions
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