The Lancet Planetary Health, June 2025

Estimates of submicron particulate matter (PM1) concentrations for 1998–2022 across the contiguous USA: leveraging measurements of PM1 with nationwide PM2·5 component data

Excess health risk estimates of exposure per unit mass concentration of fine particulate matter (PM2·5) still exhibit a wide range, potentially due to variations in aerosol size and composition. Submicron particulate matter (PM1) was recently reported to exert stronger health impacts than PM2·5 from studies in China, but an absence of long-term PM1 data in the USA has prohibited such investigations despite a wealth of cohorts.

This study aims to fill this data gap and estimate PM1 concentrations over 1998–2022 across the USA.