Parade of Tropical Waves Quell Saharan Dust Concentrations

Air quality across Trinidad has markedly improved due to the passage of Tropical Wave 05, while Saharan Dust concentrations remain elevated across Tobago.

Over the next week, periodic surges are forecast to follow tropical waves traversing the region, with air quality fluctuating between good to moderate levels, with reduced air quality mainly across Tobago

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.

All islands across the Eastern Caribbean are experiencing good air quality based on U.S. standards as of 3:00 AM Sunday 7th June 2020.

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.
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. Showers and isolated thunderstorms are forecast throughout the week, particularly during the late mornings through the afternoon, improving air quality mainly across Trinidad.

The passage of Tropical Wave 06 on Tuesday and Tropical Wave 07 on Thursday will also aid in air quality improvement.

Looking further, a surge of Saharan Dust is forecast to move in late Thursday into Friday, but Tropical Wave 08 next weekend will bring air quality improvement yet again.

Across Tobago, air quality is forecast to remain at levels near moderate through the next 5 days, with improvement possible on Thursday.

12Z 6th June 2020, CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. Credit: Weathermodels.com
12Z 6th 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.
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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