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Saharan dust covers Port-of-Spain Sunday.

Unprecedented levels of Saharan dust continued to move across Trinidad and Tobago yesterday, severely limiting visibility and reducing air quality levels.

This particular plume of Saharan dust moved off the African Coast on June 10 following two tropical waves. Air quality and visibility began to decrease last Friday, with peak concentrations occurring on Sunday.

Visibility across Trinidad reached a minimum of 700 metres, just over the distance between the St Vincent Jetty Lighthouse in Port-of-Spain and the Hyatt Regency hotel, with air quality near very unhealthy levels.

In Tobago, there was minimum visibility of three kilometres on Sunday, with air quality reaching hazardous levels for the first time in recorded history. These are the highest levels of health concern on the Air Quality Index, where serious aggravation of heart or lung disease and premature mortality in people with cardiopulmonary disease and the elderly are possible. Also, with air quality at very unhealthy to hazardous levels, there is a serious risk of respiratory effects in the general population.

The Environmental Management Agency has been monitoring air quality across Trinidad since 2015 at Port-of-Spain and Point Lisas and Signal Hill, Tobago, since late 2019 using Ambient Air Quality Monitoring Stations.

This surge of Saharan Dust has also affected the remainder of the Lesser Antilles and is now moving across the Greater Antilles, where record-breaking visibility and air quality levels are being recorded. It will continue to move west towards Central America and the US Gulf Coast.

During the hurricane season, dense plumes of Saharan dust move off the West African Coast due to stronger thunderstorms across Central Africa associated with tropical waves. 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.

Larger, more concentrated plumes of Saharan dust begin to occur in April and continue through November.

Across T&T, high concentrations of Saharan dust will persist, keeping air quality between moderate and unhealthy levels. Brief improvement is forecast for Thursday due to the passage of a tropical wave. However, another surge of dust will follow, leading to a mostly dusty end to June.