Targeting 50% air-pollution mortality reduction by 2040 requires transformative health-oriented precision emission reduction
In May 2025, the 78th World Health Assembly adopted a global roadmap to address the health effects of air pollution. Within this framework, the World Health Organization (WHO) proposed an ambitious target of reducing mortality from anthropogenic air pollution by 50% by 2040 relative to 2015. This sets a significantly higher benchmark for global air quality actions. Although some regions have lowered fine particulate matter (PM2.5) concentrations through stringent controls, further improvements face challenges due to diminishing marginal returns of homogeneous mitigation strategies. Moreover, emerging evidence indicates that health risks persist even below the WHO’s interim target of 5 μg/m3, underscoring the need for health-centric interventions. Targeted mitigation of high-risk anthropogenic sources may be essential for achieving the 2040 goal. However, uncertainties in source-specific toxicity and heterogeneous health risks amplify policy challenges, impeding the design of interventions that maximize health benefits. These challenges highlight the urgent need for an evidence-based paradigm shift from concentration-oriented emission reduction to health-oriented air quality management. Here, we postulate such a fundamental paradigm shift to address the diminishing returns of conventional approaches and maximize health benefits.
The narrowing scope
The international consensus on emission reduction has resulted in measurable declines in PM2.5 concentrations. According to the 2021 Global Burden of Disease report, air pollution remains the second leading global mortality risk factor, with 4.70 million excess deaths attributed to PM2.5. This stark reality has galvanized international consensus that the pressing need to enforce proactive and impactful measures to decrease pollutant emissions prevails.
Emission-reduction policies have markedly decreased PM2.5 concentrations, with China showing the fastest rate of air quality improvement. Since the 1960s, Europe and the United States (US) have implemented stringent air quality regulations and initiatives to restrict industrial and transportation emissions. In the US, the implementation of the Clean Air Act drove a substantial decline in PM2.5 from 13.5 μg/m3 in 2000 to 7.8 μg/m3 in 2022. In recent years, China’s action plans reduced national PM2.5 to 30 μg/m3 in 2023, a 58.33% decline in PM2.5 and a 96.14% decline in the number of heavily polluted days from 2013.
Despite a slight overall decline in PM2.5 exposure globally, it remains persistently high in certain regions. Notable improvements in air quality have occurred in Southeast Asia, East Asia, and Oceania; however, numerous low- and middle-income countries in Africa and the Middle East still experience high PM2.5 exposure. In 2020, an estimated 99% of the global population was exposed to PM2.5 levels exceeding the WHO guideline of 5 μg/m3. Currently, only 0.18% of global land area records an annual exposure below 5 μg/m3.
