Association between ambient ozone pollution and mortality from a spectrum of causes in Guangzhou, China

Ambient ozone (O₃) has emerged as an important public health issue worldwide. Previous studies found an association between O₃ and cardiorespiratory mortality. However, evidence was limited regarding the risk of O₃ on mortality from other diseases. In this study, we aimed to estimate the association between O₃ and mortality from a broad spectrum of diseases in Guangzhou, China, which has experienced a rapid increase in O₃ concentration over the past decades. Daily data were obtained on cause-specific mortality, air pollutant concentrations and weather conditions during 2013-2018. A generalized additive model with quasi-Poisson regression was applied to examine the association between O₃ and mortality from 10 broad causes and 26 refined subcategories, with adjustment of long-term and seasonal trends, weather conditions, public holidays and days of the week. We found that the threshold concentrations of O₃ were 40 μg/m³ for all-cause, non-accidental, cardiovascular and respiratory mortality. Mortality risk increased monotonically with O₃ concentrations above the threshold. Per 10 μg/m³ increase of O₃ at lag 0-3 days was associated with 0.54% (95%CI: 0.34-0.74%), 0.56% (95%CI: 0.36-0.76%), 0.59% (95%CI: 0.30-0.88%), 0.78% (95%CI: 0.33-1.24%) and 0.52% (95%CI: 0.21-0.83%) elevated risk of death from all causes, non-accidental causes, cardiovascular diseases, respiratory diseases and neoplasms, respectively. Among the subcategories, the largest effect estimate was observed in people with chronic obstructive pulmonary disease. The elderly suffered from a higher mortality risk from O₃. Stringent emission control strategies and multi-sectoral collaborations are needed to reduce the detrimental impact of O₃ on vulnerable populations.