# Spatial Cluster of Air Pollutants and Its Association with Life Expectancy, Age-Specific Mortality Risk, and Cause-Specific Mortality Rate: A County-Level Ecological Study Across the USA

## TL;DR

This study explores how clusters of air pollutants across the USA are linked to lower life expectancy and higher mortality rates, especially in older adults.

## Contribution

The study identifies specific pollutant clusters and their real-world health impacts using county-level data and latent class analysis.

## Key findings

- PM2.5 mass, PM10 speciation, and NONOxNOy were linked to reduced life expectancy.
- A severe pollutant cluster was associated with increased mortality in middle-aged and elderly populations.
- The cluster was also linked to higher mortality rates from respiratory, cardiovascular, and neoplastic diseases.

## Abstract

Air pollution has been one of the major threats to public health. The study aimed to determine latent patterns of geographical distribution of health-related air pollutants across the USA and to evaluate real-world cumulative effects of these patterns on public health metrics. It was an ecological study using county-level data on the concentrations of 12 air pollutants over 20 years. Latent class analysis was used to identify the common clusters of life expectancy-associated air pollutants based on their concentration characteristics in the final counties studied (n = 699). Multivariate linear regression analyses were then applied to assess the relationship between the LCA-derived clusters and health measurements with confounding adjustment. We found that PM2.5 mass, PM10 speciation, and NONOxNOy (the reactive nitrogen species) were associated with life expectancy and thus were included in LCA. Among five identified clusters, the one with a more severe pollutant profile was associated with a decreasing life expectancy, an increasing mortality risk among middle-aged and elderly populations (≥45 years), and an increasing mortality rate caused by chronic respiratory conditions, cardiovascular diseases, and neoplasms. Our study brings new perspectives on real-world geographical patterns of air pollution to explain health disparities across the USA.