Short-Term PM 2.5 Exposure and Cardiovascular Mortality: A Global Exposure-Response Analysis to Inform Alert Thresholds.
Yongkang Yang, Jianyu Deng, Peng Zhou et al.
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In 30 seconds
This systematic review and meta-analysis combined 100 epidemiologic studies (123 effect estimates) to characterise the global nonlinear association between short-term ambient PM2.5 exposure and cardiovascular mortality and assess an alert threshold. Each 10 μg/m³ increase in PM2.5 was associated with a pooled cardiovascular mortality risk ratio of 1.0090 (95% CI: 1.0074-1.0106). The estimated optimal alert value was 136 μg/m³ (95% CI: 129-148); the model suggested this could prevent 73.2% (95% CI: 71.8%-76.6%) of attributable deaths while affecting 32% of at-risk person-days.
Key findings
- For every 10 μg/m³ increase in short-term PM2.5, the pooled cardiovascular mortality risk ratio was 1.0090 (95% CI: 1.0074-1.0106).
- The exposure-response curve was supralinear: marginal risk flattened at ∼75-150 μg/m³ and rose sharply above 150 μg/m³.
- The estimated 2023 global cardiovascular deaths attributable to PM2.5 episodes exceeding 75 μg/m³ were 59,399 (95% CI: 38,126-82,413).
- An alert value of 136 μg/m³ (95% CI: 129-148) was estimated to prevent 73.2% (95% CI: 71.8%-76.6%) of attributable deaths while affecting 32% of at-risk person-days.
Why it matters
The analysis quantifies how cardiovascular mortality risk varies across short-term PM2.5 concentrations, rather than assuming a uniform increase in risk. Its modelled alert threshold offers a way to consider health protection alongside the disruption of alerts. These estimates may inform evaluation of warning systems, while remaining dependent on the underlying epidemiologic evidence and modelling assumptions.
What to keep in mind
The alert threshold and deaths prevented are model-based estimates derived from pooled epidemiologic studies and global exposure, population, and baseline mortality data; they are not results of a trial of an alert system.