Nausori, situated in the Tailevu Province of Fiji, occupies a strategically important location within the Rewa River delta, a low-lying coastal plain. Its coordinates, -18.0244, 178.5454, place it approximately 18 kilometers inland from the Rewa River estuary, which flows into the Pacific Ocean. The city’s terrain is predominantly flat, characteristic of deltaic environments, with gentle slopes towards the river and coastal areas. This flatness, while facilitating urban development, also contributes to potential air quality challenges. Nausori serves as a significant commercial and industrial hub for the central division of Fiji, acting as a vital link between Suva, the capital, and the interior highlands. Surrounding Nausori is a mosaic of agricultural land, primarily sugarcane fields and smallholder farms, interspersed with residential areas and pockets of mangrove forests along the Rewa River. The urban–rural gradient is relatively sharp, with agricultural activities gradually transitioning to urban development as one approaches the city center. The proximity to the Rewa River and the Pacific Ocean introduces a maritime influence, moderating temperatures but also potentially influencing the dispersion of pollutants. Industrial activity, though not extensive, is concentrated along the main transport corridors, including sawmills and small-scale manufacturing, which can contribute to localized air pollution. The relatively low elevation of the city (generally below 50 meters) limits vertical mixing of air, potentially trapping pollutants near the surface, especially during periods of stable atmospheric conditions.

Nausori’s tropical climate dictates a seasonal pattern of air quality influenced primarily by wet and dry seasons rather than the four traditional seasons. The dry season, typically spanning from May to October, often sees a slight increase in particulate matter concentrations. This is due to reduced rainfall, which limits the natural cleansing effect of precipitation, and increased agricultural burning associated with sugarcane harvesting. While winds are generally consistent throughout the year, periods of lighter breezes during the dry season can lead to a build-up of pollutants, particularly near industrial areas and busy transport routes. The wet season, from November to April, brings frequent rainfall and higher humidity, generally improving air quality by washing away particulate matter and diluting gaseous pollutants. However, periods of heavy fog, particularly in the early morning hours, can temporarily trap pollutants close to the ground, creating localized pockets of poor air quality. Temperature inversions, though less frequent than in temperate climates, can occasionally occur, especially during cooler nights, further hindering vertical mixing and exacerbating pollution. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, particularly on days with limited wind and increased agricultural activity. Outdoor activities are generally more favorable during the wet season, although vigilance is still advised during foggy mornings. The maritime influence helps to moderate extreme temperature fluctuations, but the overall impact on air quality is largely determined by rainfall patterns and agricultural practices.