Construction and verification of air quality health index in china

Abstract

Background: Air Quality Health Index (AQHI) was established in several countries and areas, and has showed validity in communicating health risks of air pollution. But there is a lack of unified AQHI in China. Methods: We contructed six indexes: AQHI_99, AQHI_98, AQHI_95, AQHI_log99, AQHI_log_98, and AQHI_log_95, by summing the excess total non-accidental mortality risks associated with PM2.5,O3, NO2, and SO2 and adjusting them to an arbitratry scale (1-10+). To adjust the distribution of the index, we logarithmic convert the sum of health risks. To avoied the maximun interference, we use the 99%, 98%, and 95% percentile of excess total non-accidental mortality risks of all counties in China as normalization factor. To verification the validity of communicating morbality and morbidity risk, we calculated the relationship between the AQHIs and morbality, anount of hospitalization, and outpatient number. According to the results, we chose the best AQHI. To test the ability of the AQHI to indicated a typical contamination event, we plotted the AQHI and air pollution concentration in several typical contamination event. And we also checked the consistency of AQHI and AQI. Results: AQHI_98 and AQHI_99 performed better in validity of communicating morbality and morbidity risk than AQI and other AQHIs. Given the current state of air pollution in China, we tended to opt for stricter standards: AQHI_98. An IQR increase of AQHI_98 was associated with a 1.0% (95% CI: 0.6 to 1.5) increase of non-accidental mortality in China and 2.0% (95% CI:1.8 to 2.1) increase of all causes hospital admissions in Beijing. This AQHI permforms good in indicating typical contamination events and does not conflict with AQI. Conclusions: We recommend AQHI_98 as Chinese AQHI. The AQHI is a more effective tool to communicate the health risk of air pollution in China.