Saharan Dust concentrations are at their peak today, with air quality levels between moderate and unhealthy for sensitive groups. While elevated levels of dust remain forecast through the weekend, dust-free days are on the horizon by the middle of next week.
What you need to know
— Saharan Dust Surges: A moderate to high concentration surge of Saharan Dust is present across Trinidad and Tobago, with moderate to occasionally high concentrations forecast to remain present through February 18th, 2024. Improvement is forecast from February 19th through February 25th, with little to no dust present.
— Impacts: Over the next five days, air quality across T&T will range between moderate and unhealthy for sensitive groups. During peak concentrations, mainly from Saturday night, and in the vicinity of blowing smoke near fires, air quality is likely to be reduced to unhealthy. After February 18th, air quality is forecast to be mostly good.
— What Should You Do: In times of unhealthy air quality, everyone should take the necessary precautions. Throughout the forecast period, unusually sensitive groups are advised to take the necessary precautions, particularly during high traffic and in the vicinity of fires.
Current AQI Levels Across T&T
The official air quality monitoring stations from the Environmental Management Agency (EMA) at Beetham, Port of Spain, Mayaro, Toco, and Point Lisas are all reporting moderate levels, with air quality levels at San Fernando at unhealthy for sensitive groups. As of Tuesday afternoon, the station at Signal Hill, Tobago, is not reporting PM2.5 or PM10 data.
Unofficial air quality monitoring stations at St. Augustine and Woodbrook report moderate air quality, while Longdenville reports unhealthy air for sensitive groups.
These measurements are 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.
Over the last 24 hours, visibility has remained at 10 kilometers at the A.N.R. Robinson International Airport at Crown Point, Tobago, and while at the Piarco International Airport, Trinidad, visibility has fluctuated between 6 and 10 kilometers.
Saharan Dust Forecast
Tuesday (February 13th) through Sunday (Feb 18th): Moderate to high concentrations of Saharan Dust across T&T and the southern half of the Lesser Antilles. Air quality: moderate to occasionally unhealthy for sensitive groups, dipping to unhealthy in high traffic and near fires/blowing smoke.
Monday (February 19th) through Sunday (February 25th): Mild to no concentrations of Saharan Dust present, generally decreasing further into the forecast period. Air quality: generally good to occasionally moderate.
What does this mean for you?
Everyone may begin to experience health effects, and members of sensitive groups may experience more serious health effects. Everyone should take the necessary precautions, particularly when peak concentrations are forecast.
From February 19th, air quality is forecast to gradually improve across Trinidad and Tobago as higher concentrations of Saharan Dust move westward. However, with elevated concentrations still present and drier conditions bringing the risk of fires, air quality is still forecast to be reduced, with further reductions in localized areas of fires, blowing smoke and dust, and high traffic.
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.
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.
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.
