Association between daily air pollution levels and asthma related emergency department visits in Al Jubail Industrial City, Saudi Arabia

Albalawi, Salem

INTRODUCTION: In the last few years, epidemiological studies have provided evidence that exposure to air pollution can aggravate symptoms in asthmatic patients. To the best of our knowledge, no study of this kind has been conducted in Saudi Arabia. The aim of this study is to investigate the statistical association between ambient air pollution and asthma emergency department visits in Al Jubail Industrial City in Saudi Arabia.

METHODS: Daily asthma emergency department visits, hourly ambient air pollutant (PM₁₀, PM_2.5, SO₂, CO, NOx), and meteorological (temperature and relative humidity) data were obtained from the Royal Commission of Al Jubail Industrial City for the period 2007 to 2011. The relative risk (RR) of asthma emergency department visits associated with the air pollution variables was estimated using time-series analysis approach, involving a generalised linear model (GLM) with Poisson regression, controlling for weather variables, day of the week and holiday indicator for lag times of 0-7 days. Relative risks (RRs) are 95% confidence intervals (CIs) are presented.

RESULTS: The single-pollutant model showed a statistically significant relationship on the day of exposure (lag 1) between asthma emergency department visits and PM₁₀ & PM_2.5. The RR increased by 1.07% for PM_2.5 (95% CI: 0.75% - 1.39%) and 0.18% for PM₁₀ (95% CI: 0.11% - 0.25%) per 10 μg/m³ increase in concentrations. In the multi-pollutant models, the associations for PM_2.5 were only showed a significant relationship on the day of exposure (lag 1) and the RR increased by 1.22% for PM_2.5 (95% CI: 0.67% - 1.77%) per 10 μg/m³ increase in concentrations. No significant associations between asthma emergency department visits and SO₂, CO & NOx were found.

CONCLUSIONS: The current levels of ambient air pollution were associated with the risk of asthma emergency department visits in Al Jubail. Reductions in air pollution levels are necessary to protect the health of the community.