Indoor air pollution is a major issue in developing countries such as India and Bangladesh, exacerbated by factors such as traditional cooking methods, insufficient ventilation, and cramped living conditions, all of which elevate the risk of health issues such as lung infections and cardiovascular diseases. With the World Health Organization associating around 3.2 million annual deaths globally to household air pollution, the gravity of the problem is clear. Yet, extensive empirical studies exploring these unique patterns and indoor pollution’s extent are missing. To fill this gap, we carried out a 6-months long field study involving over 30 households, uncovering the complexity of indoor air pollution in developing countries, such as the longer lingering time of volatile organic compounds (VOCs) in the air or the significant influence of air circulation on the spatiotemporal distribution of pollutants. We introduced an innovative Internet of Things (IoT) air quality sensing platform, the Distributed Air QuaLiTy MONitor (DALTON), explicitly designed to meet the needs of these nations, considering factors such as cost, sensor type, accuracy, network connectivity, power, and usability. As a result of a multi-device deployment, the platform identifies pollution hot spots in low- and middle-income households in developing nations. It identifies best practices to minimize daily indoor pollution exposure. Our extensive qualitative survey estimates an overall system usability score of 2.04, indicating an efficient system for air quality monitoring.