Was it better or worse? Simulating the environmental and health impacts of emissions trading scheme in Hubei province, China

Given the environmental impacts of co-pollutant emissions such as PM_2.5, SO₂, and NO_x, carbon emissions trading between corporations implemented to fulfill the global goal of mitigating climate change may improve or worsen local air quality and public health. It is therefore necessary to measure the environmental and health impacts between different regions involved in emissions trading scheme (ETS). This study proposed a unifying framework that incorporated a number of models and databases to explore the spatial changes in CO₂ emissions due to ETS in Hubei, one of China's ETS pilots, simulate the distribution of atmospheric co-pollutants on a 3 km × 3 km resolution, and compare the cause-specific mortality attributable to co-pollutants varying in time and cross regions between with and without the ETS. The simulation shows that in general the ETS improved air quality in large parts of Hubei, as indicated by the notable decline in both PM_2.5 concentrations and the proportion of heavily polluted areas throughout Hubei. However, an increase in PM_2.5 concentrations after the implementation of ETS was observed in some areas of major cities, such as Wuhan, Xiaogan, Ezhou, Huangshi and Yichang, resulting in negative impacts on human health locally. The findings could assist policymakers in better understanding the complex impacts of ETS on environmental and human health, therefore serving as a useful reference for interregional efforts to speed up the development of China's ETS.