Ozone pollution in Chinese cities: Assessment of seasonal variation, health effects and economic burden

The ground-level ozone (O₃) concentration in the urban regions of China has become an increasingly noticeable environmental problem in recent years. Many epidemiological studies have reported the association between O₃ pollution and mortality, only a few studies have focused on the O₃-related mortality and corresponding economic effects at the Chinese city and province level. This study reports the seasonal variation of ground-level O₃ in 338 cities of China during the year 2016 and evaluates its effect on premature mortality and economic loss. It further illustrates the differences in cause-specific mortality outcomes of the log-linear and linear model, two of the prominently used methods for estimating health effects. In 2016, the annual average daily maximum 8-h O₃ concentration in China ranged between 74 and 201 μg/m³ (138 ± 24.7 μg/m³). 30% of the total population was exposed to >160 μg/m³ O₃ concentration (Chinese national ambient air quality standard) and about 67.2% urban population lived in exposure above the WHO recommended O₃ concentrations (100 μg/m³). The estimated national O₃-attributable mortality was 74.2 × 10³ (95% CI: 16.7×10³–127×10³) in the log-linear model, whereas, the total O₃-related mortality using the linear model was 69.6 × 10³ (95% CI: 16.2 × 10³–115 × 10³). The exposure to O₃ caused a nationwide economic loss of about 7.6 billion US$ (range: 1.7–12.9) in 2016. This study uniquely provides most comprehensive coverage of the Chinese cities for O₃ associated mortality utilizing ground level measurement data for 2016 and presents a measurable assessment to the policymakers of China for streamlining their efforts on air quality improvement and O₃ containment.