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Otjiwarongo, nestled in the Otjozondjupa Region of Namibia, occupies a strategic position within the country’s central landscape. Its coordinates, -20.4642, 16.6528, place it on a relatively flat, expansive plateau, part of the larger Kalahari Basin. The terrain surrounding Otjiwarongo is predominantly savanna grassland, transitioning into scrubland further afield, punctuated by occasional rocky outcrops and dry riverbeds. The city’s location is significant as it lies along a major transportation corridor, the B1 highway, connecting Windhoek to the north and Okahandja to the south, facilitating trade and movement of goods and people. This highway contributes to localized air pollution, particularly from vehicle emissions. While not directly adjacent to a major river, the area receives occasional runoff from the nearby Omboroko Mountains, influencing localized humidity and potentially affecting atmospheric stability. The urban–rural gradient around Otjiwarongo is gradual, with agricultural activities, primarily cattle ranching and some crop farming (maize and millet), dominating the surrounding areas. This agricultural activity, while vital to the regional economy, can contribute to dust pollution, especially during dry periods and planting/harvesting seasons. The relatively low elevation (approximately 1,200 meters above sea level) and the broad, open landscape promote good air dispersion under favourable wind conditions, but can also exacerbate dust events. The absence of significant industrial belts within immediate proximity mitigates some pollution risks, though the highway and agricultural practices remain key factors shaping the local air quality profile.

Otjiwarongo experiences a semi-arid climate characterized by distinct wet and dry seasons, profoundly influencing its air quality. The dry season, typically spanning from May to October, is marked by consistently high temperatures and minimal rainfall. This period often witnesses elevated dust concentrations due to strong winds sweeping across the exposed savanna and agricultural lands. The lack of vegetation cover during this time intensifies the problem. Temperature inversions, common during the cooler nights of the dry season, can trap pollutants near the ground, leading to localized air quality degradation. Conversely, the wet season (November to April) brings sporadic rainfall, which helps to cleanse the atmosphere by washing away particulate matter and reducing dust levels. However, the onset of the wet season can also be accompanied by periods of fog, particularly in the early morning, which can temporarily trap pollutants and reduce visibility. Wind patterns are generally consistent throughout the year, but stronger winds are more frequent during the dry season. Sensitive groups, such as children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, particularly during periods of high wind and dust. Outdoor activities are generally more favourable during the wet season, although sudden downpours can impact visibility and air quality temporarily. The agricultural cycle also plays a role; planting and harvesting activities during the wet season can generate dust, while the dry season’s increased livestock activity can contribute to odour and ammonia emissions.