A multi-pollutant air quality health index for assessing mortality risk of ischemic heart disease in Jinan, China

To investigate the exposure-response relationship between air pollutants and mortality risk of ischemic heart disease (IHD) in Jinan, establish a tailored Air Quality Health Index (AQHI) for IHD mortality risk assessment, and evaluate the performance of this integrated index in quantifying the effects of air pollutants on IHD mortality. A distributed lag non-linear model was employed to quantitatively evaluate the exposure-response relationship and lag effects between air pollutants and IHD mortality risk. An AQHI for IHD was developed, and its predictive performance for excess risk (ER) of IHD mortality was compared with that of the conventional Air Quality Index (AQI). Results of the cumulative lag analysis showed that for each 10 µg/m³ increase in the concentrations of PM_2.5(lag03), NO₂ (lag05), SO₂ (lag07), and O₃ (lag07), and each 1 mg/m³ increase in CO (lag04), the ER of IHD mortality increased by 0.914% (95% CI: 0.059–1.776), 1.744% (95% CI: 0.005–3.512), 13.802% (95% CI: 7.398–20.588), 1.285% (95% CI: 0.355–2.223), and 12.240% (95% CI: 2.735–22.625), respectively. When AQHI and AQI increased by one interquartile range (IQR), AQHI showed a consistently stronger effect on IHD mortality risk than AQI. Subgroup analyses confirmed that in male, female, age ≥ 65 years, married, other marital status, junior high school or below, warm season and cold season subgroups, the AQHI-associated ER per IQR increment was consistently higher than that of AQI. Air pollutants have significant lag effects on IHD mortality. Compared with the conventional AQI, the locally established Jinan-specific AQHI shows better applicability for air quality classification and stronger predictive power for IHD mortality risk in the local population.