The sources of health-threatening air pollutants and CO2 emissions differ significantly, despite both mainly originating from fossil fuel combustion. A 2017 analysis of emission inventories reveals that 86% of anthropogenic CO2 emissions were from the energy and industrial sectors, with coal combustion contributing 97% and 50% of these emissions respectively (Fig. 1a). However, coal combustion in these sectors accounted for only 17% of primary PM2.5 emissions (Supplementary Fig. 1).
The domestic sector, relying on coal and solid biomass, contributed 38% of PM2.5 and 22% of SO2 emissions. Poor air supply, mixing, and emission control in household stoves using low-quality fuels are significant factors (Ref 20). Despite contributing only 4% to CO2 emissions, the domestic sector was responsible for over a quarter of premature deaths from ambient PM2.5 exposure (Fig. 1b). In contrast, the energy generation sector, a major CO2 emitter, accounted for only 10% of these deaths. This aligns with previous studies (Ref 21, Ref 22).
Certain subsectors contribute to health damage without significant CO2 emissions, such as non-combustion industrial processes, agricultural fertilizer application, and crop residue burning (Supplementary Table 1). Although crop residue combustion emits CO2, it is considered carbon neutral (Ref 23). These “non-synergistic subsectors” account for 23% of premature deaths attributable to the five sectors assessed.
Seven subsectors were identified as major contributors to health damage, each responsible for over 100,000 premature deaths (Fig. 1c). These include bituminous coal combustion in the domestic, energy, and industrial sectors; diesel emissions; hydraulic cement and iron production; and agricultural activities. Notably, the health impact of agricultural activities is significant due to NH3 emissions, even though they are not major CO2 contributors.
The ratio of health damage to CO2 emissions varies significantly across subsectors, from 0.094 in industrial dry natural gas combustion to 22 in domestic unorganized waste combustion. This highlights the need for coordinated strategies to balance air pollution reduction and decarbonization.
Spatial Heterogeneity in Contributions to Health Damage and CO2 Emissions
High-resolution data integration reveals spatial disparities in contributions to health damage and CO2 emissions. Densely populated areas like the eastern and central regions and the Sichuan Basin show higher contributions to health damage than CO2 emissions (Fig. 2a). Hubei had the highest ratio (3.9), followed by Henan and Chongqing. In contrast, Inner Mongolia had a lower health impact despite significant CO2 emissions.
Population density significantly influences the spatial distribution of the health damage to CO2 emissions ratio. A log-linear regression at the city level shows a positive correlation between population density and the ratio of each city’s contribution to nationwide PM2.5-related health damage versus CO2 emissions (Fig. 2c). This correlation is stronger in cities with higher reliance on solid fuels for domestic energy.
Monetized Social Costs of CO2 Emissions and PM2.5 Exposure-Related Health Damage
Monetizing health damage and climate impacts using a uniform value of statistical life (VSL) of $1.33 million per death and a social cost of carbon (SCC) of $100 per ton of CO2 (Methods) shows that for 36 synergistic subsectors, health damage costs often exceed climate impact costs for half of the subsectors (Fig. 1c). Higher VSL estimates would further emphasize the near-term health benefits of CO2 emission reductions (Ref 12, Ref 29).
Comparing monetized health damage and climate impacts with sectoral GDP reveals that integrated costs of 42 economic sectors equal 20% of total GDP. In most sectors, these costs are below 5% of GDP, but exceed GDP in four sectors including electric power production and metal processing (Supplementary Fig. 7). This highlights the need for decarbonizing energy-intensive industries.
Integrating Costs from Health Damage Modifies Control Priorities
We propose a unified indicator that combines social costs from CO2 climate impacts and PM2.5 health damage to harmonize control strategies. In 2017, integrated costs for seven subsectors exceeded $100 billion, with bituminous coal combustion in energy generation being the highest. Other significant contributors include industrial coal use, diesel vehicles, and cement and steel production (Supplementary Table 1).
Spatial analysis shows that regions with high integrated costs are densely populated areas with high pollutant and CO2 emissions. Cities like Chongqing, Zhengzhou, and Shanghai are major contributors, with health costs comprising 51%-84% of the integrated costs.
Provinces like Jiangsu, Guangdong, and Inner Mongolia rank high in social costs from climate change but lower in integrated costs due to less health damage. In contrast, densely populated inland provinces rank higher in integrated costs. Chongqing shows the largest gap between these rankings.