National PM2.5 spatiotemporal model integrating intensive monitoring data and land use regression in a likelihood-based universal kriging framework in the United States: 2000-2019

Environ Pollut. 2024 Nov 27:125405. doi: 10.1016/j.envpol.2024.125405. Online ahead of print.

Abstract

Nationwide PM2.5 exposure models typically rely on regulatory monitoring data as the only ground-level measurements. In this study, we develop a high-resolution spatiotemporal PM2.5 model for the contiguous United States from 2000 to 2019 with dense monitoring data at both regulatory and residential sites. Specifically, we combine publicly-available data from 1843 regulatory monitors with our own set of multiple 2-week measurements at 939 residential locations. As we show, these additional data enhance the spatiotemporal prediction capabilities of the model. The model can handle varying data densities and regional variations; it predicts two-week average PM2.5 concentrations at fine spatial scale for the contiguous United States. Cross-validation performance indicates a spatial R2 of 0.93 and a root mean square error (RMSE) of 1.19 (μg/m3), and a temporal R2 of 0.85 and RMSE of 2.05 (μg/m3). Regional spatial R2 ranged from 0.80 (northwest) to 0.93 (northeast and central). Over time, the average PM2.5 across the United Stats decreased from 7.6 μg/m3 in 2000 to 4.7 μg/m3 in 2019. Our model effectively captured local PM2.5 gradients, highlighting its ability to address fine-scale variations related to local sources and roadways.

Keywords: exposure assessment; fine particulate matters; fine-scale monitors; spatiotemporal model.