AbstractBackgroundOn December 30th, 2013, the Hong Kong government implemented the Air Quality Health Index (AQHI) to reduce short-term impacts of air pollution on the population. However, whether air quality alert programs, such as the AQHI, reduce morbidity is still questionable. Using a quasi-experimental design, we conducted the first evaluation of the AQHI in Hong Kong focusing on respiratory morbidity.MethodInterrupted time series with Poisson segmented regression from 2010 to 2016 were used to detect any sudden or gradual changes in emergency respiratory hospital admissions, adjusted for air pollutants (NO2, SO2, PM10, O3), temperature and humidity, when the AQHI policy was implemented. Findings were validated using three false policy periods. We also assessed changes by specific respiratory diseases (respiratory tract infections (RTI), asthma, chronic obstructive pulmonary disease and pneumonia) and by age.ResultsFrom January 1st, 2010-December 31st, 2016, 10576.98 deseasonalized, age- and sex-standardized hospital admissions for respiratory diseases occurred in Hong Kong. On implementation of the AQHI, RTI admissions immediately dropped by 14% (relative risk (RR) 0.86 95% confidence interval (CI) 0.76-0.98). In age specific analysis, immediate reductions in hospital admissions, were only apparent in children for RTI (RR 0.84, 95% CI 0.74-0.96) and pneumonia (RR 0.88, 95% CI 0.60-0.96).ConclusionHong Kong’s AQHI helped reduced hospital admissions in children, particularly for RTI and pneumonia. To maximize the health benefits of the policy, at risk groups need to be able to follow the behavioral changes recommended by the AQHI index.
A New Multipollutant, No-Threshold Air Quality Health Index Based on Short-Term Associations Observed in Daily Time-Series Analyses
