Air Quality and Health Co-Benefits of Carbon Emissions Reduction and Air Pollution Control in Guangzhou, China

Abstract

Both climate change mitigation and air pollution control policies are important for improving air quality and public health. However, the combined effects of these policies on both PM2.5 and ozone concentrations, and their associated health impacts, have rarely been assessed at the city-level. This study builds an integrated modeling framework to assess the impacts of different low-carbon transitions and end-of-pipe controls on PM2.5 and ozone air quality and their premature mortality in the megacity of Guangzhou. Results show that the implementation of both deep carbon mitigation and aggressive air pollution control policies results in the largest reductions in air pollutant emissions, reducing the city’s pollutant emissions to 34-51% of the 2020 levels by 2035. Consequently, the population-weighted PM2.5 concentration in 2035 will be reduced by 5 μg/m3 compared to the baseline scenario. However, the ozone concentration will increase by 35 μg/m3 due to the reduction scheme in Guangzhou (i.e., a VOC-limited regime), which diminishes the titration effect of NO on ozone. These changes in concentrations of PM2.5 and ozone are estimated to avoid 1.4 (95% CI: 0.6-1.9) thousand premature deaths annually, accounting for only 9% of the total mortality in the baseline. If not only Guangzhou city but also the other seven neighboring cities aggressively reduce air pollutant emissions according to the most stringent scenario, the avoided deaths from PM2.5 and ozone reductions will increase to 3.6 (95% CI: 2.5-4.7) thousand, or 26% of the total mortality in the baseline. Transport and industry are most important for the abatement of the air pollutant emissions, while emission reductions in solvent use sector can offset the side effects of reduced NOx in mitigating ozone pollution.

Keywords: co-benefits, air pollution control, low-carbon pathways, health impact, megacities