Saharan Dust continues to take a hiatus from the Caribbean region for the next ten days as a west Atlantic high-pressure system prevents dust from moving eastward from Africa. As a result, T&T and the Caribbean region are forecast to see mostly good air quality. However, increased dryness may lead to bushfires. Combined with high-traffic periods or industrial activity, local air quality could be degraded.
What you need to know
— Saharan Dust Surges: No Saharan Dust surges are forecast over the next ten days, with longer-range modelling showing no dust surges nearing T&T through the end of January.
— Impacts: Over the next seven to ten days, air quality across Trinidad and Tobago is forecast to remain between good and occasionally moderate levels.
— What Should You Do: 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 Point Lisas and Arima report good air quality levels, while at San Fernando and Beetham, Port of Spain, air quality is temporarily at moderate. The station at Signal Hill, Tobago, is not reporting PM2.5 or PM10 data as of Saturday night.
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 remained unaffected by Saharan Dust and smoke at the A.N.R. Robinson International Airport at Crown Point, Tobago, and at the Piarco International Airport, Trinidad.
Saharan Dust Forecast
No Saharan Dust surges are forecast to move across Trinidad and Tobago and the Caribbean region over the next ten days.
Longer range models also keep dust near the west coast of Africa through the end of January, but there is decreasing confidence the further models depart from the seven-day time period.
Through the next ten days, air quality levels across Trinidad and Tobago are forecast to remain between good and occasionally moderate. Air quality may be further reduced near bush or landfill fires or during high-traffic periods.
While no Saharan Dust is forecast to be present, haze is still possible through the forecast period. Haze is a suspension in the air of extremely small, dry particles invisible to the naked eye and sufficiently numerous to give the air an opalescent appearance.
What does this mean for you?
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.
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.
