Assessing the impact of intense urbanization, ambient air pollution and temperature on hospital visits for respiratory diseases in Rwanda

Respiratory diseases represent a significant global health burden, contributing to high rates of death and disability. This study aims to investigate the interactive effects of temperature and ambient air pollution with a focus on differences in urbanization levels on hospital visits for Chronic obstructive pulmonary disease (COPD) and Acute Respiratory Infections (ARIs) over Rwanda. The sector territories were used and categorized into municipalities and agglomerations. Descriptive statistical analysis was performed to summarize and explore the data characteristics while principal components multivariate analysis was applied to generate urban, temperature and air quality indexes. The correlations between indexes and health parameters were examined using Spearman’s (\(\:{\uprho\:}\)) and Kendall’s (\(\:{\uptau\:}\)) rank correlations. The results indicate that municipalities exhibited higher PM_2.5 (39.26 ± 13.22 µg/m³) and NO₂ (21.20 ± 4.89 µg/m³) levels compared to agglomerations (34.08 ± 11.38 µg/m³ for PM_2.5, and 19.10 ± 5.14 µg/m³ for NO₂). These levels were associated with incidence rates for COPD (0.173 ± 0.046 and 0.170 ± 0.037 for municipalities and agglomerations, respectively) and ARIs (0.056 ± 0.003 and 0.046 ± 0.004 for municipalities and agglomerations, respectively). All observed correlations were positive (\(\:p\le\:0.05\)). For all sectors, the strongest correlations were between respiratory disease incidences and air quality index (\(\:{\uprho\:}\) = 0.776; \(\:{\uptau\:}\) = 0.584 for COPD incidences, and \(\:{\uprho\:}\) = 0.672; \(\:{\uptau\:}\) = 0.494 for ARIs incidences). COPD incidences showed the strongest correlation with temperature index in agglomerations (\(\:{\uprho\:}\) = 0.649; \(\:{\uptau\:}\) = 0.469) while strong correlation coefficients of (\(\:{\uprho\:}\) = 0.702; \(\:{\uptau\:}\) = 0.532) and (\(\:{\uprho\:}\) = 0.684; \(\:{\uptau\:}\) = 0.512) were observed for COPD incidences and ARIs incidences respectively with air quality index in municipalities. On the other hand, significant positive correlations were observed between urban index and ARIs in all sectors (\(\:{\uprho\:}\) = 0.518; \(\:{\uptau\:}\) = 0.366) and in municipalities (\(\:{\uprho\:}\) = 0.513; \(\:{\uptau\:}\) = 0.368) but the prevalence of respiratory diseases was more closely linked to air quality rather than simply the population size or density in municipalities. The findings of this study are valuable for assessing environmental challenges related to land use and for developing long-term strategies to mitigate its impacts on respiratory health. Future studies are required to explore the connection between additional urban factors, various pollutants, and respiratory health outcomes to provide a more detailed understanding of these correlations.