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Porto Alexandre, nestled on the Atlantic coast of Angola’s Namibe Province at coordinates -15.8000, 11.8500, is a port city of approximately 55,494 inhabitants. Its geography is defined by a relatively flat coastal plain, transitioning inland to a semi-arid landscape characterized by sparse vegetation and rocky outcrops. The city’s location directly on the Atlantic Ocean profoundly influences its climate and, consequently, its air quality. The Benguela Current flows northward along this coastline, creating cool, dry conditions and frequent coastal fog. This current also limits rainfall, contributing to a generally arid environment. Porto Alexandre’s function as a major port for the region means a concentration of shipping activity and associated industrial processes – including mineral loading and processing – within and around the city limits. The urban-rural gradient is sharp; immediately inland lies a sparsely populated, arid zone. Dust from this interior, combined with sea spray and industrial emissions, forms the basis of the city’s unique air quality challenges. The terrain offers limited natural dispersion of pollutants, particularly during temperature inversions common along the coast. The surrounding landscape lacks significant vegetation to act as a natural filter, exacerbating the impact of local emission sources.

Porto Alexandre experiences a distinct wet and dry season, rather than traditional four seasons. The dry season, spanning roughly May to October, is characterized by consistently low humidity, strong onshore winds, and frequent coastal fog. This period often sees elevated particulate matter concentrations due to windblown dust from the interior and increased industrial activity linked to peak shipping demands. November to April marks the wet season, bringing sporadic rainfall and slightly improved air quality as precipitation helps to settle dust. However, the increased humidity can also trap pollutants closer to the ground, leading to localised air quality issues. February and March are typically the wettest months, offering the most favourable conditions for outdoor activity. Temperature inversions, common throughout the year but particularly pronounced during the cooler dry season mornings, can trap pollutants, worsening air quality. Sensitive groups – children, the elderly, and those with respiratory conditions – should limit strenuous outdoor activity during these periods. The prevailing winds, blowing from the ocean, can transport pollutants inland, impacting communities beyond the immediate port area. Monitoring wind patterns is crucial for predicting pollution dispersion.