# Impact of Ambient PM₁₀ and SO₂ Levels on Intensive Care Unit Admissions Due to Cardiopulmonary Diseases in a Tertiary Care Hospital

## TL;DR

The study finds that higher PM₁₀ pollution is linked to more ICU admissions for lung and heart issues, but not higher mortality.

## Contribution

This study is the first to examine the link between PM₁₀ and ICU admissions with a one-month lag for cardiovascular cases.

## Key findings

- Higher PM₁₀ levels were significantly associated with increased pulmonary ICU admissions.
- PM₁₀ showed a delayed effect on cardiovascular ICU admissions when using a one-month lag model.
- SO₂ levels were not significantly linked to ICU admissions or mortality.

## Abstract

Ambient air pollution, especially particulate matter (PM₁₀) and sulfur dioxide (SO₂), has been implicated in exacerbating cardiopulmonary diseases. While emergency department visits have been widely studied, the impact of pollution on intensive care unit (ICU) admissions and mortality is less understood. This retrospective observational study aimed to evaluate the association between monthly air pollutant levels and ICU admissions for cardiopulmonary conditions, as well as in-hospital mortality.

We retrospectively analyzed 6,112 ICU admissions in a tertiary hospital from January 2012 to November 2019. Using defined inclusion criteria, 227 pulmonary and 344 cardiovascular ICU admissions were selected. Monthly PM₁₀ and SO₂ levels were obtained from official air monitoring stations. A one-month lag model was applied for cardiovascular admissions. Multivariate models were used to assess associations, and results were reported with 95% confidence intervals (CIs).

Higher PM₁₀ levels were significantly associated with pulmonary ICU admissions (β=0.017; 95% CI: 0.003–0.031; P=0.020) and with cardiovascular admissions using a one-month lag structure (β=0.018; 95% CI: 0.005–0.030; P=0.006). SO₂ showed no significant associations. No significant relationship was observed between air pollution and in-hospital mortality. Chronic kidney disease (HR=1.309; 95% CI: 1.031–1.663; P=0.027) and higher Simplified Acute Physiology Score (SAPS) scores (HR=1.012; 95% CI: 1.006–1.017; P<0.001) were independent mortality predictors.

This study indicates that long-term exposure to PM₁₀ significantly affects ICU hospitalization rates for both pulmonary and cardiac conditions, particularly reflecting delayed effects in cardiovascular admissions, without a corresponding impact on in-hospital mortality.