Saharan Dust concentrations are forecast to significantly increase from Saturday evening, with air quality and visibility set to be affected across the Eastern Caribbean. Dust concentrations are forecast to be elevated into next week.
What you need to know
— Saharan Dust Surges: A high to significant concentration surge of Saharan Dust is forecast to arrive across Trinidad and Tobago and the Lesser Antilles, with improvement forecast to begin from March 1st, with no other surges forecast during the next ten days.
— 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 29th, air quality is forecast to be mostly good to moderate.
— 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 San Fernando, Point Lisas, and Scarborough are all reporting moderate levels, while Mayaro, Arima and Beetham are reporting good air quality. As of Friday afternoon, the station at Toco is not reporting PM2.5 or PM10 data.
Unofficial air quality monitoring stations at Longdenville, St. Augustine and Woodbrook report good to moderate air quality.
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 the Piarco International Airport, Trinidad.
Saharan Dust Forecast
AM through early PM Saturday (Feb 24th): Mild to moderate concentrations of Saharan Dust across T&T and the southern half of the Lesser Antilles. Air quality: good to moderate, occasionally unhealthy for sensitive groups in high traffic and near fires/blowing smoke.
Late PM Saturday (Feb 24th) through PM Sunday (Feb 25th): High to significant concentrations of Saharan Dust across T&T and the Lesser Antilles. A dust advisory from the Caribbean Institute of Meteorology and Hydrology is in effect. Air quality: moderate to unhealthy for sensitive groups, dipping to unhealthy in high traffic and near fires/blowing smoke.
Monday (Feb 26th) through Friday (Mar 1st): Moderate concentrations of Saharan Dust across T&T and the southern half of the Lesser Antilles. Air quality: moderate to occasionally unhealthy for sensitive groups in high traffic and near fires/blowing smoke.
Saturday (Mar 2nd) through Monday (Mar 3rd): Little to no Saharan Dust across T&T and the Windwards. Air quality: Mostly good, to occasionally moderate. Air quality may reduce further in high traffic and near fires/blowing smoke.
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 on Saturday night into Sunday.
From March 1st, 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.
