Saharan Dust Is Here. Air Quality, Visibility Reduced Across T&T

View of Saharan Dust across Port of Spain, taken from Westmoorings on Monday morning. Photo Credit: Karen Johnstone

As forecast, the Saharan Dust has returned across Trinidad and Tobago, as well as the Lesser Antilles, with a vengence. Most islands across the Eastern Caribbean are experiencing moderate air quality levels, based on U.S. standards as of 2:00 PM Monday 7th October 2019. Saharan Dust will continue to move across the Lesser Antilles through the week, gradually decreasing in concentrations.

Air quality is forecast to be reduced to moderate levels continuing through Monday gradually returning to good levels later this week across T&T. Islands in the Leewards, air quality may drop to levels that are unhealthy for sensitive groups over the next 24-36 hours. Sensitive groups and those with respiratory ailments are advised to take the necessary precautions.

Presently, minimal concentrations of Saharan Dust are present across Trinidad and Tobago, with air quality at moderate levels. Across the remainder of the Eastern Caribbean, air quality is at good levels to levels near unhealthy for sensitive groups.

Note that the Environmental Management Agency (EMA) air quality monitoring stations are presently recording AQI values at moderate levels, based on T&T’s air quality standards, while other air quality monitoring stations are reporting air quality at good levels, based on United States standards.

Visibility across Trinidad has reduced to 8 kilometers while in Tobago, remains at 10 kilometers and above.

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, dust concentrations are forecast to peak today, Monday, across Trinidad and Tobago, gradually improving by the late week. Air quality is forecast to degrade to moderate levels, and at times, unhealthy for sensitive groups, particularly northern Windward and the Leeward Islands.

00Z October 7th, 2019 CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing the thicker plumes of Saharan Dust mainly remaining across the Eastern Atlantic. Credit: Weathermodels.com
00Z October 7th, 2019 CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing the thicker plumes of Saharan Dust mainly remaining across the Eastern Atlantic. Credit: Weathermodels.com
5-Day Air Quality Index (based on United States EPA Standards), Saharan Dust Forecast For Trinidad and Tobago. Saharan Dust is forecast remain across Trinidad and Tobago this week.
5-Day Air Quality Index (based on United States EPA Standards), Saharan Dust Forecast For Trinidad and Tobago. Saharan Dust is forecast remain across Trinidad and Tobago this week.

Generally, through the next 5 days, air quality is forecast fluctuate between moderate and good levels across Trinidad and Tobago.

What does this mean for you?

Through Wednesday, and even through the end of the week, sensitive groups, such as children, the elderly and persons who suffer from respiratory ailments and allergies, may need to avoid prolonged exertion outdoors. Mild to moderate concentrations of Saharan Dust forecast. See below for more detail.

Good Air Quality

Good Air Quality

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

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.

Unhealthy for Sensitive Groups

Unhealthy for Sensitive Groups Air Quality

AQI – 101 to 150

What does this mean for you?

Members of sensitive groups may experience health effects. The general public is not likely to be affected. There is an increasing likelihood of respiratory symptoms in sensitive individuals, aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease & the elderly.

Who needs to be concerned?

Sensitive groups include people with heart or lung disease, older adults, children, and teenagers.

What should you do?

Sensitive groups: Reduce prolonged or heavy exertion. It’s OK to be active outside, but take more breaks and do less intense activities. Watch for symptoms such as coughing or shortness of breath.

People with asthma should follow their asthma action plans and keep quick-relief medicine handy.

If you have heart disease: Symptoms such as palpitations, shortness of breath, or unusual fatigue may indicate a serious problem. If you have any of these, contact your health care provider.

Air purification: At this level, the air is polluted. Turn on your air purifier, running at a high level.

Ventilation: Please close doors windows, as the air is 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.

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.

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, as we move through July into September, these frequent tropical waves also aid in improving air quality.

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.

Saharan Dust Precautions
Saharan Dust Precautions
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