Another Surge of Saharan Dust Forecast To Arrive For Carnival 2020

A dense plume of Saharan Dust is moving across the Eastern Caribbean, as forecast over the last week. Air quality has declined across the entire region

As of 12:00 PM Thursday 20th February 2020, air quality is at moderate levels with concentrations of Saharan Dust slowly decreasing across Trinidad and Tobago.

Air Quality Index across Trinidad and Tobago as of 12:00 PM Thursday 20th February 2020.
Air Quality Index across Trinidad and Tobago as of 12:00 PM Thursday 20th February 2020.

Visibility across Trinidad is at 7 kilometers while across Tobago, 10 kilometers as reported by Piarco and Crown Point observations.

Across the Eastern Caribbean, air quality alerts, bulletins, and advisories remain in effect for several islands. In Antigua and Barbuda, where air quality is already at moderate levels based on US Standards, a Saharan Dust Air Quality Bulletin is in effect from “late Tuesday until Thursday (today).”

In Barbados, a Weather Information Statement was issued advising of the plume of Saharan Dust east of the region, affecting Barbados from early Wednesday through Friday.

In Martinique, their Alert Procedure has been activated as air quality is at their highest alert level (Very Bad, Red, 10/10). In Guadeloupe, their information procedure has been activated as air quality is poor.

In Trinidad and Tobago, the Trinidad and Tobago Meteorological Service has issued several social media posts concerning the approaching Saharan Dust, but there are no alerts watches or warnings in effect for the country.

Most islands across the Eastern Caribbean are experiencing moderate air quality levels, based on U.S. standards as of 12:00 PM Thursday 20th February 2020.

Air Quality Index across the Eastern Caribbean as of 12:00 PM Thursday 20th February 2020

The Environmental Management Agency (EMA) air quality monitoring stations are presently recording AQI values at good to moderate levels in Trinidad. In Tobago, air quality levels are moderate for PM2.5 (particulates the size of 2.5 micrometers and smaller, usually associated with increases in Saharan Dust, vehicle exhaust and smoke). Saharan Dust is on the decrease across the country.

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 slowly decrease across Trinidad and Tobago and the remainder of the Eastern Caribbean through the next 24 hours.

After nightfall on Saturday into Sunday, a mild to moderate concentration of dust is forecast to arrive across Trinidad, Tobago, and the Southern Windwards, with peak concentrations occurring Sunday into Monday.

Visibility will be notably reduced through today (Thursday), coinciding with the highest concentrations of dust.

Air quality will also be reduced to levels that are generally moderate to at times, unhealthy for sensitive groups across Trinidad and Tobago.

00Z February 20th, 2020, CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing the thicker plumes of Saharan Dust mainly remaining across the Eastern Atlantic, with a surge of dust moving across our region. Credit: Weathermodels.com
00Z February 20th, 2020, CAMS Copernicus Atmospheric Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing the thicker plumes of Saharan Dust mainly remaining across the Eastern Atlantic, with a surge of dust moving across our region. 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 to fluctuate across Trinidad and Tobago over the next several days.
5-Day Air Quality Index (based on United States EPA Standards), Saharan Dust Forecast For Trinidad and Tobago. Saharan Dust is forecast to fluctuate across Trinidad and Tobago over the next several days.

Generally, through the next 5 days, air quality is forecast to vary from good to moderate levels.

Beyond the 5-day period, Saharan Dust will persist into Wednesday, with another possible significant surge forecast by the end of next week.

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 as there is more 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.

Unhealthy for Sensitive Groups

Unhealthy for Sensitive Groups Air Quality

Level 3 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 surges of dust during this time of year are due to the Harmattan, a season in the West African subcontinent that occurs between the end of November and the middle of March. During this season, a predominant northeasterly trade wind (dubbed the Harmattan Winds) blows from the Sahara Desert over Western Africa into the Gulf of Guinea.

The Harmattan Winds over Central & Western Africa (Source)
The Harmattan Winds over Central & Western Africa (Source)

During this period, a ridge of high pressure stays over the central Sahara Desert, and the Intertropical Convergence Zone (ITCZ) remains over the Gulf of Guinea. The Harmattan wind accelerates when it blows across the mountain massifs of Northwest Africa. If its speed is high enough and it blows over dust source regions, it lifts the dust and disperses it. Dust that makes it into the upper levels of the atmosphere can then get transported across the Atlantic Ocean and affect the Eastern Caribbean. These Saharan Dust outbreaks tend to be milder in the Eastern Caribbean than the dust outbreaks associated with West African thunderstorms driving dust into the upper atmosphere from April 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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