Abstract
<title>Abstract</title> <p>Background Ambient particulate matter is a leading global driver of respiratory morbidity, yet epidemiological evidence from sub-Saharan Africa remains disproportionately scarce relative to the region’s exposure burden. No prior study has examined short-term associations between particulate matter and acute respiratory morbidity in Ghana. Objectives The primary objective was to estimate short-term associations between PM₂.₅/PM₁₀ concentrations and acute respiratory outpatient presentations. The secondary objective was to evaluate the feasibility of linking continuous environmental monitoring data with routinely collected electronic health records in this setting. Methods We conducted Ghana’s first time-stratified case-crossover pilot study, linking two years (January 2023–December 2024) of continuous federal-equivalent-method PM₂.₅/PM₁₀ monitoring with electronic outpatient records from the University of Ghana Hospital and Students’ Clinic. Acute respiratory presentations (upper respiratory infection [URI], pneumonia, asthma; ICD-10–defined) were identified through a six-stage diagnostic filtering cascade. Conditional logistic regression, adjusted for temperature and relative humidity, estimated odds ratios (ORs) per interquartile-range (IQR) increase in pollutant concentration across single-day and cumulative lags (0–7 days). Results Among 9,511 acute respiratory presentations identified from 213,241 outpatient records, URI accounted for 8,805 cases (925.7 per 1,000 catchment population). Each IQR increase in PM₂.₅ (14.70 µg/m³) and PM₁₀ (51.49 µg/m³) was significantly associated with increased odds of URI presentation (PM₂.₅ OR = 1.038, 95% CI: 1.010–1.068; PM₁₀ OR = 1.030, 95% CI: 1.008–1.052). Lag-specific analyses revealed the strongest effects at lag 1 (PM₂.₅ OR ≈ 1.07; PM₁₀ OR ≈ 1.06), with elevated risks persisting across cumulative lags up to seven days (PM₂.₅ OR ≈ 1.09; PM₁₀ OR ≈ 1.06). Associations were strongest among females and during the dry Harmattan season. Pneumonia showed directionally consistent but non-significant associations; asthma showed none. Sensitivity analyses restricting to higher-pollution days reproduced and modestly strengthened the primary URI associations. The environmental monitoring stream achieved 96.03% data completeness after quality control, demonstrating the operational feasibility of linking continuous air quality data with routine clinical records in this setting. Conclusions This pilot provides the first case‑crossover evidence linking short‑term particulate exposure to acute respiratory morbidity in Ghana, demonstrating both a robust PM–URI association and the feasibility of linking continuous air quality monitoring with routine clinical records. These findings establish proof of concept for the AIRCLARE‑Ghana research programme and support the case for a fully powered study to clarify effects on pneumonia and asthma.</p>