Particulate Matter Exposure and Accelerated Cardiovascular Aging: Mechanistic Evidence, Biomarker Integration, and the PACA Framework.

Particulate matter exposure, particularly PM2.5 and ultrafine particles, is a well-established risk factor for cardiovascular morbidity. However, whether pollution-associated cardiovascular abnormalities represent transient toxicity, cumulative injury, developmental programming, aging-like phenotypes, or a genuine alteration in the trajectory of cardiovascular aging remains unresolved. Here, we propose the Pollution-Accelerated Cardiovascular Aging (PACA) framework as a conceptual, hypothesis-generating approach for interpreting this distinction. Rather than proposing new molecular mechanisms, we integrate established pathways, including mitochondrial and redox dysfunction, genomic and epigenetic alterations, cellular senescence and senescence-associated secretory phenotype signaling, impaired proteostasis, endothelial dysfunction, and autonomic dysregulation within an explicit evidentiary framework. We also consider the pulmonary neural cardiac axis as a potential route through which pulmonary sensory activation may influence autonomic regulation, calcium handling, and cardiac electrophysiological function. To distinguish exposure-associated toxicity from evidence consistent with altered cardiovascular aging, we introduce a Temporal-Evidence Matrix that integrates exposure kinetics, life-course timing, persistence and recovery after exposure cessation, exposure response relationships, and longitudinal change relative to age-referenced comparators. Persistence, incomplete recovery, or cumulative loss of cardiovascular reserve support chronic or sustained injury but do not independently establish accelerated aging. Stronger evidence for PACA requires repeated longitudinal demonstration that particulate exposure is associated with a greater rate or altered trajectory of aging-related cardiovascular or biological change than expected from chronological aging. Finally, we propose a tiered biomarker framework that separates candidate biological-aging integrators from mechanistic stress and injury indicators and contextual inflammatory markers, while treating vascular and cardiac functional or imaging measures as complementary cardiovascular phenotypes. The principal contribution of PACA is therefore evidentiary rather than mechanistic, providing a structured approach for testing whether particulate exposure is associated with cardiovascular toxicity alone or with an altered cardiovascular-aging trajectory.