Impacts of climate change on future air quality and human health in China

Significance

More intense extreme events are projected under future climate change. However, the impacts of climate extremes on future air quality and associated health implications are not well recognized and are rarely quantified in China, with an enormous health burden from air pollution. Here, we estimate the climate-driven air pollution mortality in China and find that future climate change is likely to exacerbate air pollution mortality, largely influenced by the more intense extreme events such as stagnation events and heat waves. Our analysis provides quantitative assessments and insights regarding the links between climate extremes, future air quality, and public health, suggesting that extreme weather events may be an important mechanism by which climate change will affect air quality, and especially fine particulate matter.

Abstract

In recent years, air pollution has caused more than 1 million deaths per year in China, making it a major focus of public health efforts. However, future climate change may exacerbate such human health impacts by increasing the frequency and duration of weather conditions that enhance air pollution exposure. Here, we use a combination of climate, air quality, and epidemiological models to assess future air pollution deaths in a changing climate under Representative Concentration Pathway 4.5 (RCP4.5). We find that, assuming pollution emissions and population are held constant at current levels, climate change would adversely affect future air quality for >85% of China’s population (∼55% of land area) by the middle of the century, and would increase by 3% and 4% the population-weighted average concentrations of fine particulate matter (PM _2.5) and ozone, respectively. As a result, we estimate an additional 12,100 and 8,900 Chinese (95% confidence interval: 10,300 to 13,800 and 2,300 to 14,700, respectively) will die per year from PM _2.5 and ozone exposure, respectively. The important underlying climate mechanisms are changes in extreme conditions such as atmospheric stagnation and heat waves (contributing 39% and 6%, respectively, to the increase in mortality). Additionally, greater vulnerability of China’s aging population will further increase the estimated deaths from PM _2.5 and ozone in 2050 by factors of 1 and 3, respectively. Our results indicate that climate change and more intense extremes are likely to increase the risk of severe pollution events in China. Managing air quality in China in a changing climate will thus become more challenging.