Assessment of air pollutant distribution patterns and potential health risks in hospitals in Northwestern Nigeria

This study assessed the concentration, distribution pattern, and potential health risks of gaseous and particulate pollutants in selected teaching hospitals across three northwestern states. A cross-sectional, instrument-based environmental assessment was conducted across indoor, outdoor, and junction environments of the hospitals. Air pollutant concentrations were measured using the RASI700 BIO Portable Gas Analyzer through spot measurements (30–120 s) at breathing height (1.2–1.5 m), with triplicate readings obtained for each microenvironment. Data were statistically analyzed using Minitab 22. Health risks were estimated using the HQ and HI, while the AQI provided an overall air quality classification. Results showed clear spatial variations in pollutant concentration distribution. Indoor, outdoor, and junction measurements showed variable pollutant levels: CO (1.0–4.4 ppm), NO (3.3–5.2 ppm), NO2 (0.4–1.2 ppm), SO2 (0.2–1.0 ppm), CH4 (0.7–9.5 ppm), H2S (6–9 ppm), VOC (9.4–12.1 ppm), and PM2.5 (1.6–2.5 µg/m³). However, indoor air showed higher VOC (11.0–12.1 ppm) accumulation, while outdoor and junction areas recorded elevated NO2 (0.7–1.2 ppm) and SO2 (0.7–1.0 ppm) levels. PCA identified components dominated by NO₂, H₂S, and VOCs, indicating these pollutants contributed most to variance in air quality indicators. Cluster analysis grouped hospital sites distinct clusters, revealing site-specific emission patterns with junction sites forming the most polluted clusters, followed by outdoor and indoor areas. AQI values ranged from unhealthy to hazardous, with the highest levels recorded at AKTH indoor and outdoor, ABUTH outdoor and junction microenvironments, and KDSTH junction microenvironment for the duration of measurement. The calculated HQ and HI values indicated potential non-carcinogenic risks in several environments. HQ values for NO₂, SO₂, and H₂S exceeded unity (HQ > 1) across all the microenvironments, whereas CO, CH₄, and PM₂.₅ remained below unity (HQ < 1). Consequently, the cumulative HI was > 1 in all assessed microenvironments. The findings revealed instantaneous air quality challenges within hospital environments with pollutant concentrations varying across the different microenvironments. Routine air quality monitoring, improved ventilation, waste management control, and regulatory enforcement are essential to mitigate health risks and enhance environmental safety in hospital settings.