San Juan Air Quality Index (AQI)

Loading live AQI data...

Loading historical AQI trends...

San Juan, situated within the larger San Juan/Laventille region of Trinidad and Tobago, presents a unique urban geography. Located at 10.6500°N, -61.4500°W, the city occupies a relatively flat coastal plain, gently rising towards the Northern Range mountains inland. This proximity to the Caribbean Sea significantly influences local weather patterns and, consequently, air quality. San Juan isn’t heavily industrialised itself, but lies within reach of industrial zones concentrated further west towards Port of Spain and Point Lisas, a major petrochemical complex. Agricultural activity, primarily small-scale farming, surrounds the urban core, contributing to seasonal biomass burning. The urban-rural gradient is relatively sharp, transitioning quickly from densely populated residential areas to more open, vegetated landscapes. The city’s position within a natural funnel created by the hills can trap pollutants, particularly during periods of calm winds. Drainage patterns are complex, with several small rivers and streams flowing towards the coast, potentially carrying pollutants from inland sources. The prevailing trade winds, however, generally offer some dispersion, though their effect is lessened during the calmer wet season. The city’s relatively low elevation contributes to humidity and potential for temperature inversions, exacerbating pollution events.

San Juan experiences a distinct wet and dry season, rather than traditional four seasons, profoundly impacting air quality. The dry season (January to May) typically sees the poorest air quality. Lower rainfall means less atmospheric cleansing, and increased dust from drier ground surfaces. Winds are generally calmer, allowing pollutants from nearby industrial areas and agricultural burning to accumulate. February and March are often the most challenging months for respiratory health. The onset of the wet season (June to December) brings significant improvement. Frequent rainfall effectively washes pollutants from the air, and higher humidity can suppress dust. However, the wet season also brings increased potential for localised flooding, which can mobilise pollutants from contaminated sites. September and October, peak months for rainfall, generally offer the cleanest air. Temperature inversions, common throughout the year but more pronounced during the transition periods, can trap pollutants near ground level. Sensitive groups – children, the elderly, and those with pre-existing respiratory conditions – should limit strenuous outdoor activity during the dry season and monitor conditions closely. Increased vigilance is also advised during periods of Saharan dust intrusion, which can occur sporadically.