Publications·January 29, 2024
This flagship report from the AiR-Climate-Health (ARCH) platform—co-initiated by Peking University with partners including the Chinese Academy of Environmental Planning/Sciences, China CDC, and Fudan University—argues for putting health outcomes at the center of China’s air-quality and climate strategies. It synthesizes evidence across five domains: (1) air pollution & health, (2) climate change & health, (3) two-way interactions between climate and air pollution, (4) compound/combined exposures and their synergistic health effects, and (5) health co-benefits from coordinated air- and climate-action. The report positions a health-first approach as the most effective way to prioritize measures, monitor progress, and deliver multi-win outcomes (environment–health–economy).
The health stakes: large and uneven
Globally, ~6.67 million premature deaths in 2019 were linked to long-term air-pollution exposure, with >99% of people breathing air that exceeds WHO guidelines—burdens that fall disproportionately on lower- and middle-income countries. China has achieved major improvements since 2013, yet PM₂.₅, O₃, and NO₂ levels remain above WHO guideline values in many settings; O₃ has emerged as a growing challenge despite PM gains. Acute and chronic effects are both important: short-term rises in PM₂.₅/O₃/NO₂ are associated with increases in all-cause mortality within 24–48 hours, while long-term PM₂.₅ exposure is associated with 8–11% higher all-cause mortality per +10 µg/m³. Vulnerability is not uniform: older adults, infants, people with cardiopulmonary disease, and lower-income communities bear greater risk. Toxicology and mechanistic studies highlight inflammation, oxidative stress, and epigenetic changes (e.g., DNA/RNA methylation) as key pathways.
Climate change is a health issue—directly and indirectly
Warming has accelerated globally (≈+1.14–1.15°C vs pre-industrial in the past decade), with China warming faster than the global average (~+0.26°C/decade from 1951–2021). Health risks arise through direct pathways (heat waves, cold spells, floods, typhoons) and indirect pathways (food security, infectious-disease ecology, air quality). In China, non-optimal temperatures are linked to hundreds of thousands of cardiopulmonary deaths annually; preterm birth risk rises with heat/cold exposure; and mental-health burdens increase with thermal stress and disasters. Vector-borne diseases such as dengue show strong temperature sensitivity (Pearl River Delta: ~+101% transmission risk per +1°C in one analysis), and water/food-borne diseases respond to heat and humidity. Projections indicate rising heat-related excess mortality through the 2030s–2090s under high-emissions scenarios.
How climate and air pollution interact
The report details two-way links:
Climate → air quality: Warming and extremes (heat waves, drought, cold surges, typhoons) alter natural emissions (biogenic VOCs, wildfires, dust) and anthropogenic emissions (e.g., heating demand), and reshape chemistry/transport/deposition.
Air pollution → climate: Aerosols scatter/absorb radiation and seed clouds, exerting cooling or warming; dust modifies surface radiation; wildfire smoke affects clouds, albedo, and vegetation. Structural policy shifts (e.g., large aerosol reductions) can unmask warming; China’s post-2013 PM reductions likely raised regional temperatures while worsening tropospheric ozone chemistry in some seasons—illustrating the need for co-optimized policies.
Compound/combined exposures amplify risk
Co-exposures (e.g., heat + ozone, cold + PM₂.₅, or pollution + extreme precipitation) create synergistic health harms greater than the sum of parts. Heat waves and O₃ often co-occur and are projected to become ~26× more frequent by the 2080s compared with today; high temperatures also magnify O₃-related mortality, while cold conditions enhance NO₂-associated risks. Evidence on dust–pollen co-exposure is mixed, but the trend toward more extremes (heat, drought, wildfires, strong typhoons) argues for compound-risk monitoring, early warning, and response playbooks.
What coordinated air–climate policy delivers for health
Natural-experiment evidence shows large health returns from clean-air measures. During the 2008 Beijing Olympics, rapid emission controls lowered PM₂.₅ and were associated with declines in all-cause and cardiovascular mortality and higher birthweights. Over the long term, China’s Air Pollution Action Plan and Blue Sky campaigns have improved lung function and cognition in population studies—though more cohort-based evaluation is needed. On the climate side, health benefits are often modelled: high-temperature early-warning systems reduce mortality (e.g., international case studies); in China, meteorology–health alerts show promise but need broader evaluation. Crucially, air-quality measures also cut CO₂: 2013–2020 clean-air actions yielded an estimated 2.43 billion tonnes of CO₂ reductions, catalyzing energy transition. Looking forward, by 2035, air-quality-driven low-carbon policies could lower major air-pollutant emissions 6–32% and CO₂ by ~22%; by 2060, carbon-neutrality pathways would dramatically reduce PM₂.₅ exposure and resolve chronic pollution, avoiding millions of cases and raising life expectancy—though population ageing could partly offset gains. Modelled scenarios toward the 2°C target indicate double-digit percentage declines in PM₂.₅- and O₃-attributable mortality by 2050, with large medical-cost savings.
What the report recommends (health-first governance)
Re-anchor targets to health. Use health impact and risk-avoidance metrics to prioritize measures and track progress; align national standards and plans with WHO AQGs (stepwise).
Plan for compound risk. Build monitoring, analytics, and early-warning for heat–ozone, cold–PM, wildfire smoke, dust, and flood events; develop actionable playbooks for municipal response.
Integrate air + meteorology + health data. Stand up integrated monitoring (regulatory AQ, meteorology, remote sensing) and research platforms; standardize QA/QC, exposure metrics, and open data for evaluation.
Invest in evidence and equity. Expand cohort studies at low concentrations and on pollutant components; map regional and population heterogeneity (age, poverty, chronic disease) to target interventions.
Co-optimize air & climate portfolios. Evaluate co-benefits and trade-offs (e.g., aerosol reduction vs O₃ chemistry); identify least-regret measures (clean energy, industrial controls, transport electrification, building efficiency, clean household energy).
Institutionalize health impact assessment. Use ex-ante health-benefit appraisal for environmental/energy policies; fund adaptive O&M and capacity building so pilots become operational services.
Why this matters now
China’s “dual-carbon” pathway will reshape energy and industry; if designed with health at the core, it can accelerate air-quality gains, shrink disease burden, and improve resilience to climate extremes. The report’s message is clear: synchronize air-pollution control with climate mitigation/adaptation; measure what matters most (health); and build the data, institutions, and human capital to sustain progress.
Key words
Air pollution–health; PM₂.₅ / O₃ / NO₂; non-optimal temperature; compound exposure (heat+O₃, cold+PM₂.₅); inflammation/oxidative stress/epigenetics; vector-borne and water/food-borne disease; clean-air co-benefits; carbon neutrality; integrated monitoring; early warning; health impact assessment; equity/vulnerability.