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ORIGINAL RESEARCH article

Front. Built Environ.
Sec. Indoor Environment
Volume 11 - 2025 | doi: 10.3389/fbuil.2025.1528453

Analysis of the influence of exogenous factors on indoor air quality in residential buildings

Provisionally accepted
Deborah Nibagwire Deborah Nibagwire 1*Godson Ana Godson Ana 1Egide Kalisa Egide Kalisa 2Gratien Twagirayezu Gratien Twagirayezu 3Abdou Kagabo Safari Abdou Kagabo Safari 2Jaques Nsengiyumva Jaques Nsengiyumva 2
  • 1 Pan African University for Life and Earth Science Institute (PAULESI), University of Ibadan, Ibadan, Nigeria
  • 2 College of Science and Technology, University of Rwanda, Kigali, Rwanda
  • 3 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences (CAS), Guiyang, Guizhou Province, China

The final, formatted version of the article will be published soon.

    Indoor air pollution presents a significant global health risk, yet the influence of outdoor air pollution and meteorological factors on indoor air quality is not well understood. This study investigates these impacts in 88 naturally ventilated households across urban, suburban, and industrial areas, with no indoor smoking or cooking. Air quality measurements were continuously recorded for 24 hours a day over six consecutive days during the wet season. The findings reveal that the outdoor PM2.5 levels consistently exceeded indoor levels, with weekday concentrations higher than on weekends. Specifically, urban PM2.5 levels averaged 34.8 µg/m³ outdoors and 31 µg/m³ indoors on weekdays, compared to 33.1 µg/m³ outdoors and 31.5 µg/m³ indoors on weekends. Indoor CO2 levels were notably higher, peaking at 525.7 ppm in urban areas on weekdays and 576.9 ppm on weekends, driven by increased occupancy and poor ventilation, particularly in suburban areas (880.4 ppm on weekdays and 807.5 ppm on weekends). The average indoor/outdoor (I/O) ratio for PM2.5 was 0.94, indicating that indoor concentrations are about 94% of outdoor levels, signifying significant infiltration of outdoor pollution. In contrast, the I/O ratio for CO2 was 1.47, suggesting indoor levels were 47% higher due to limited ventilation and indoor sources. This study concludes that outdoor air pollution and meteorological factors significantly affect indoor air quality in Kigali, Rwanda, highlighting the need for effective management of both outdoor pollution sources and indoor conditions.

    Keywords: Indoor air quality, outdoor air pollution, Meteorological influence, PM2.5 infiltration, exogenous factors

    Received: 23 Nov 2024; Accepted: 31 Jan 2025.

    Copyright: © 2025 Nibagwire, Ana, Kalisa, Twagirayezu, Kagabo Safari and Nsengiyumva. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Deborah Nibagwire, Pan African University for Life and Earth Science Institute (PAULESI), University of Ibadan, Ibadan, Nigeria

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.