Ambient air pollution exposure and COVID-19 related hospitalizations in Santiago, Chile

Morbidity and mortality from several diseases are increased on days of higher ambient air pollution. We carried out a daily time-series analysis with distributive lags to study the influence of short-term air pollution exposure on COVID-19 related hospitalization in Santiago, Chile between March 16 and August 31, 2020. Analyses were adjusted for temporal trends, ambient temperature, and relative humidity, and stratified by age and sex. 26,579 COVID-19 hospitalizations were recorded of which 24,501 were laboratory confirmed. The cumulative percent change in hospitalizations (95% confidence intervals) for an interquartile range increase in air pollutants were: 1.1 (0.2, 2.0) for carbon monoxide (CO), 0.30 (0.0, 0.50) for nitrogen dioxide (NO₂), and 2.7 (1.9, 3.0) for particulate matter of diameter ≤ 2.5 microns (PM_2.5). Associations with ozone (O₃), particulate matter of diameter ≤ 10 microns (PM₁₀) and sulfur dioxide (SO₂) were not significant. The observed effect of PM_2.5 was significantly greater for females and for those individuals ≥ 65 years old. This study provides evidence that daily increases in air pollution, especially PM_2.5, result in a higher observed risk of hospitalization from COVID-19. Females and the elderly may be disproportionately affected.