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Iharan̈a, nestled within the Antsiranana Province of Madagascar, occupies a geographically significant position on the northeastern coast. Its coordinates, -13.3750, 50.0100, place it within a region characterized by a dramatic urban–rural gradient. The city itself is relatively small, with a population of approximately 15,000, suggesting a primarily rural character transitioning towards a minor urban centre. The surrounding landscape is dominated by the Sambirano coastal plain, a fertile region known for its agricultural production, particularly vanilla, cloves, and cocoa. This proximity to agricultural zones introduces potential sources of air pollutants, including pesticide drift and emissions from agricultural machinery, though the scale is likely limited given the city’s size. Iharan̈a benefits from its location near the Indian Ocean, which influences local weather patterns and can provide some degree of natural air cleansing through sea breezes. The terrain is gently undulating, rising slightly inland from the coast, which can occasionally contribute to localized temperature inversions, trapping pollutants closer to the ground. Further inland, the landscape transitions to rolling hills and eventually the slopes of Montagne d'Ambra, a significant biodiversity hotspot. The coastal location also means the city is susceptible to maritime influences, including salt spray and potential impacts from shipping activity, although the port activity in Antsiranana is further north. The overall urban fabric is likely characterized by a mix of traditional Malagasy architecture and more modern structures, with a relatively low density of industrial activity.

Iharan̈a’s tropical climate dictates a distinct wet and dry season pattern, profoundly influencing its air quality. The wet season, typically spanning from November to April, brings frequent rainfall and high humidity. This period generally sees improved air quality as precipitation effectively washes away particulate matter and dilutes gaseous pollutants. The increased cloud cover also reduces solar radiation, which can limit the formation of ground-level ozone. However, heavy rainfall can also lead to increased soil erosion and runoff, potentially carrying dust and other pollutants into the air. The dry season, from May to October, is characterized by lower rainfall and increased sunshine. This period often experiences a build-up of pollutants due to reduced cleansing rainfall and increased evapotranspiration, leading to higher concentrations of particulate matter and potentially volatile organic compounds (VOCs) from vegetation. Calm wind conditions during certain periods of the dry season can exacerbate this issue, creating stagnant air masses and promoting the accumulation of pollutants. Fog, particularly in the mornings, can also trap pollutants near the ground. During the transition months (April/May and October/November), air quality can be highly variable, influenced by shifting wind patterns and rainfall. Sensitive groups, such as children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, particularly during periods of stagnant air or fog. Outdoor activities are generally more favourable during the wet season, although caution should be taken during periods of heavy rainfall and potential flooding.