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Nova Olinda do Norte, nestled within the heart of Amazonas, Brazil, occupies a strategically important position along the Purus River, a major tributary of the Amazon River. Its coordinates, -3.8878, -59.0939, place it within a predominantly lowland Amazonian landscape, characterized by dense rainforest and a remarkably flat terrain. The city’s elevation is minimal, averaging around 60 meters above sea level, contributing to a stable atmospheric layer that can, under certain conditions, trap pollutants. The surrounding landscape is overwhelmingly dominated by terra firme forests and várzea forests (seasonally flooded forests), with the Purus River acting as a vital transportation artery and a source of livelihood for the local population. The urban footprint of Nova Olinda do Norte is relatively small, exhibiting a clear urban–rural gradient as it expands outwards. While the core area features typical Brazilian urban characteristics – a central plaza, commercial zones, and residential areas – the periphery quickly transitions into agricultural lands, primarily focused on small-scale farming and cattle ranching. There are no significant industrial belts immediately adjacent to the city; however, logging activities and river transport contribute to localized air quality concerns. The region's remoteness and dependence on river transport mean that air pollution sources are often diffuse, stemming from vehicle emissions, agricultural practices, and the burning of biomass for cooking and land clearing, all influenced by the prevailing Amazonian climate and riverine dynamics.

Nova Olinda do Norte experiences a tropical climate with distinct wet and dry seasons, profoundly influencing its air quality profile. The wet season, typically spanning from November to May, brings consistently high rainfall and humidity, generally leading to improved air quality as precipitation washes away particulate matter and dilutes gaseous pollutants. Stronger winds associated with convective storms also help disperse pollutants. Conversely, the dry season (June to October) presents a greater air quality challenge. Reduced rainfall and lower humidity create conditions conducive to the accumulation of pollutants. Temperature inversions, where a layer of warm air traps cooler air near the ground, are more frequent during this period, exacerbating the problem. Agricultural burning, a common practice for land preparation, significantly contributes to particulate matter pollution during the dry season, particularly in August and September. Fog, a relatively infrequent occurrence but impactful when it does happen, can also trap pollutants close to the ground, leading to temporary spikes in air quality concerns. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, limiting prolonged outdoor exposure and avoiding areas with visible smoke. While the wet season generally offers respite, heavy rainfall can occasionally lead to increased mold and fungal spores, impacting indoor air quality. Maintaining good ventilation and addressing moisture issues are crucial throughout the year.