Impact of Air Pollution on Respiratory Hospital Admissions in Makkah during Hajj and the COVID-19 Pandemic

Impact of Air Pollution on Respiratory Hospital Admissions in Makkah during Hajj and the COVID-19 Pandemic

Air pollution remains a major public health challenge in rapidly urbanising cities, particularly during large mass gatherings. This study examined the short-term associations between ambient concentrations of particulate matter (PM₁₀) and nitrogen dioxide (NO₂) and hospital admissions for respiratory diseases in Makkah, Saudi Arabia, from 2019 to 2022. Using time-series Poisson regression models adjusted for seasonality, meteorological factors, long-term trends, and demographic characteristics, we evaluated variations in pollutant effects across three distinct periods: Hajj events, the COVID-19 lockdown, and non-event days. Relative risks were estimated per interquartile range (IQR) increase in pollutant concentrations.

Results showed that PM₁₀ and NO₂ exposures were significantly associated with increased respiratory admissions during the Hajj period, with the strongest effects observed at lag 0 per IQR increase (PM₁₀: RR = 1.066; 95% CI: 1.030–1.104; NO₂: RR = 1.162; 95% CI: 1.118–1.207). In contrast, these associations weakened or became non-significant during the COVID-19 lockdown, likely reflecting reductions in emissions and altered healthcare-seeking behaviour and mobility patterns.

Overall, the findings highlight the amplified respiratory health risks of air pollution during Hajj and support targeted, event-specific air quality management and public health interventions in Makkah.

Keywords: air pollution, respiratory diseases, hospital admissions, Hajj, COVID-19, public health, Makkah