The impact of air pollution on paediatric hospital admissions for acute lower respiratory infections (ALRI) in Makkah, Saudi Arabia, during Hajj events

Air pollution is a major public health concern, particularly for children who are more susceptible to its harmful respiratory effects. Makkah experiences elevated levels of air pollution due to the influx of religious visitors, vehicular emissions, and traffic during the annual Hajj. The resulting increase in air pollutants raises concerns about respiratory health risks among children, yet local research has focused little on this vulnerable group. This study investigated the association between air pollutants (PM10 and NO2) and pediatric admissions from acute lower respiratory infections (ALRI) among children aged 5–14 years in Makkah, Saudi Arabia, from January 2021 to December 2022. The study period overlapped with the COVID-19 pandemic, which was considered when interpreting the findings. Daily time-series log-linear Poisson regression models were used, adjusting for temporal trends using natural cubic splines, meteorological variables, and sociodemographic factors. Relative risks were estimated per interquartile range increase in pollutant concentrations across lag days 0–2. Hajj-specific associations were assessed using interaction terms for the Hajj and non-Hajj periods. Exposure to NO2 was significantly associated with an increased risk of same-day ALRI admissions in children during the Hajj events (RR = 1.033; 95% CI: 1.003–1.063 per IQR rise) but not outside the Hajj events. In contrast, PM10 effects were non-significant. The findings suggest that NO2, but not PM10, was associated with ALRI admissions during Hajj, highlighting the need for Hajj-focused traffic-emission control and child health protection strategies in Makkah.Implications: Increased NO2 levels during Hajj are associated with higher pediatric ALRI admissions, highlighting the need for targeted air quality management during mass gatherings. Strengthening emission controls, traffic regulation, and monitoring can reduce exposure and protect vulnerable children.