A Comprehensive Review of Air Quality Science, Measurement, Health Impacts, and Policy Pathways for Clean Air

Abstract

Air pollution remains the leading environmental risk factor for premature mortality worldwide, driven primarily by fine particulate matter (PM₂.₅) and ozone exposure. This review synthesizes advances in atmospheric science, exposure assessment, health evidence, and policy design to inform effective clean‑air strategies. We summarize the physical and chemical formation pathways of key pollutants, evaluate the expanding measurement toolkit from regulatory reference monitors to satellite remote sensing and dense low‑cost sensor networks, and compare modeling architectures that convert emissions and meteorology into concentration fields and population exposure. We assess the strength of the epidemiological evidence linking air pollution to cardiovascular, respiratory, and metabolic outcomes, emphasizing developments in causal inference, non‑linear concentration–response relationships, and the global transferability of risk functions. The review highlights source apportionment insights that prioritize action on residential solid fuel use, traffic, industry, power generation, agriculture, and natural sources. We discuss policy architectures—ambient standards, emission controls, market instruments, and integrated climate‑air frameworks—and quantify health, climate, and economic co‑benefits of mitigation. Six original illustrative figures and three methodological tables are provided to aid teaching and practice. We conclude with a research and policy agenda centered on equity, transparency, sensor fusion, accountability, and sustained implementation