Vanono, a small settlement within the Toamasina Province of Madagascar, occupies a geographically significant position along the eastern coast. Located at approximately -16.0397° latitude and 49.4607° longitude, the town sits near the Indian Ocean, a defining feature influencing its climate and potential air quality challenges. The surrounding landscape is characterized by a gradual transition from coastal plains to low-lying hills, typical of Madagascar’s eastern escarpment. This terrain, while generally gentle, can create localized microclimates and influence wind patterns, impacting pollutant dispersion. Vanono’s proximity to Toamasina, Madagascar’s largest port city and industrial hub, is a crucial factor. While Vanono itself is a relatively small, sparsely populated area (estimated at 14,000 residents), it exists within a broader urban-rural gradient. Toamasina’s industrial activities, including processing of agricultural products (particularly vanilla, cloves, and coffee) and port-related operations, can contribute to regional air pollution that may affect Vanono. Agricultural zones, prevalent in the surrounding areas, introduce potential sources of particulate matter from land clearing and burning practices, particularly during the dry season. The coastal location also means Vanono is susceptible to sea salt aerosol deposition, which can impact visibility and respiratory health. The elevation is relatively low, generally below 50 meters, minimizing the potential for significant vertical mixing of air pollutants, potentially trapping them closer to ground level. The urban character is primarily rural, with limited infrastructure and a reliance on traditional livelihoods, though increasing connectivity to Toamasina is gradually altering this.

Vanono’s tropical climate dictates a distinct wet and dry season pattern, profoundly influencing its air quality. The wet season, typically spanning November to April, brings consistent rainfall and high humidity. This period generally sees improved air quality due to frequent precipitation washing away particulate matter and increased vegetation uptake of pollutants. However, periods of intense rainfall can also lead to flooding, potentially releasing mould spores and other allergens into the air. The dry season, from May to October, presents a more complex picture. Reduced rainfall means less natural cleansing of the atmosphere, allowing pollutants to accumulate. The drier conditions also increase the likelihood of agricultural burning, a significant source of smoke and particulate matter, especially in October and November as farmers prepare fields for the next planting season. Temperature inversions, where cooler air is trapped beneath a layer of warmer air, are less frequent than in temperate climates but can occur, particularly during calmer periods in August and September, leading to stagnant air and pollutant build-up. Wind patterns are generally easterly, influenced by the trade winds, but can vary significantly. Fog, though not a frequent occurrence, can exacerbate air quality issues by trapping pollutants near the ground. Sensitive groups, such as children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, particularly during periods of agricultural burning or when visibility is reduced. Outdoor activities are generally more favourable during the wet season, although vigilance regarding potential allergens is advised.