Significant Surge of Saharan Dust Forecast By End of Next Week

Air quality across Trinidad and Tobago have been on the decline as Tropical Wave 07 moves west and Saharan Dust concentrations increase.

Saharan Dust concentrations are forecast to peak overnight through Saturday with air quality at moderate levels.

Note that in localized areas, further reduced air quality will occur in areas with smoke, fires, and high vehicular traffic. Visibility across Trinidad and Tobago is at 10 kilometers.

Most islands across the Eastern Caribbean are experiencing good air quality based on U.S. standards as of 2:00 PM Friday 12th June 2020.

GOES-EAST GEOCOLOR Imagery since June 10th showing a significant plume of Saharan Dust moving across the far Eastern Atlantic, progressing slowly westward. (RAMMB/CIRA/NASA)
GOES-EAST GEOCOLOR Imagery since June 10th showing a significant plume of Saharan Dust moving across the far Eastern Atlantic, progressing slowly westward. (RAMMB/CIRA/NASA)

However, we have been monitoring an impressive and significant surge of Saharan Dust moving off the coast of Africa over the last three days. This surge of dust is forecast to arrive next weekend following the passage of Tropical Wave 10. This is forecast to bring some of the highest concentrations of Saharan Dust for 2020 to date across the Eastern Caribbean.

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

What we expect

Based on the latest dust modeling, air quality across Trinidad and Tobago is forecast to fluctuate between levels that are good to moderate over the next 5 days.

Between today (Friday) and Saturday, the ongoing surge of Saharan Dust will peak in concentrations, declining particularly across Trinidad by late Sunday through Tuesday due to the passage of Tropical Wave 08.

By late Tuesday through Saturday next week, Tropical Waves 09 and 10, in combination with the first arrival of the Intertropical Convergence Zone will keep air quality across both islands at good levels.

By next Saturday, Saharan Dust will return to the region, lingering through the end of June as a significant surge of dust moves across the entire Atlantic.

00Z 12th June 2020, CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. Credit: Weathermodels.com
5-Day Air Quality Index based on the Saharan Dust Forecast For Trinidad and Tobago.

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 below for more detail in the Saharan Dust forecast.

Good Air Quality

Good Air Quality

Level 1 AQI – 0 to 50

What does this mean for you?

At this level, air quality is considered satisfactory, and air pollution poses little or no risk to public health. It’s a great day to be active outside.

Who needs to be concerned?

No one.

What should you do?

Sensitive Groups: Sensitive groups, children and the elderly do not need special protection.

Air purification: It is recommended to run an air purifier in auto-mode, so it automatically reacts to changes in air quality.

Ventilation: It is good for ventilation.

Masks: No masks are needed.

Outdoor Activity: Very suitable for outdoor exercise and activities.  

Moderate Air Quality

Moderate Air Quality

Level 2 AQI – 51 to 100

What does this mean for you?

Air quality is acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Who needs to be concerned?

Unusually sensitive people: Consider reducing prolonged or heavy exertion. Watch for symptoms such as coughing or shortness of breath. These are signs to take it easier.

Everyone else: It’s a good day to be active outside.

What should you do?

Sensitive Groups: Sensitive groups such as those with respiratory ailments, children and the elderly are advised to reduce outdoor physical exertion, and reduce the time of their stay outdoors, especially in areas with heavy traffic.

Air purification: At this level, the air is slightly polluted. It is recommended to turn on your air purifier, running at a low level, at a minimum.

Ventilation: Please close windows, as the air is slightly polluted.

Masks: Wearing a mask during outdoor activity is recommended, particularly in areas with heavy traffic.

Outdoor Activity: It is recommended to stay indoors and avoid outdoor exercise.

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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