Air Pollution Linked to Increased Hospital Admissions for Lower Respiratory Infections: Study Finds - Video

A new research showed that long-term exposure to PM2.5, PM10, NO2 and ozone (O3) air pollution is associated with more hospital admissions for lower respiratory tract infections in adults. The associations were stronger in men, people over 65 years of age and those diagnosed with hypertension. The results have been published in the journal Environment International.

Researchers from the Barcelona Institute for Global Health assessed the effect of air pollution on hospital admissions for lower respiratory infections in adults, and investigated the existence of subgroups that are particularly vulnerable to these infections.

The study involved 3,800,000 adults from the COVAIR-CAT cohort. The research team used exposure models to estimate annual average concentrations of PM2.5, PM10, NO2 and ozone during the warm season (May-September) between 2018 and 2020 at the participants' residences. Information on hospital admissions, mortality and comorbidities was obtained from various administrative databases. The study included hospital admissions for all lower respiratory infections and, separately, the subgroup of hospital admissions for influenza and pneumonia. A statistical model was then used to assess the association between air pollution and hospital admissions.

Specifically, elevated levels of air pollution were associated with approximately three times higher rates of hospital admissions for lower respiratory infections among people aged 65 years and older compared with younger people.

In addition, exposure to elevated levels of NO2, PM2.5 or PM10 (but not O3) was associated with about a 50% increase in hospital admissions in men, while the association was about 3% higher in women.

“The association between air pollution and hospital admissions for lower respiratory tract infections was observed even at pollution levels below current EU air quality standards,” says Anna Alari, ISGlobal researcher and first author of the study. “It is crucial to adopt stricter air quality standards, as more ambitious measures to reduce air pollution would decrease hospital admissions and protect vulnerable populations,” she adds.

Reference: Anna Alari, A., Ranzani, O., Milà, C., Olmos, S., Basagaña, X., Dadvand, P., Duarte-Salles, T., Nieuwenhuijsen, M., Tonne, C. Long-term exposure to air pollution and lower respiratory infections in a large population-based adult cohort in Catalonia. Environment International, 2025. Doi: https://doi.org/10.1016/j.envint.2024.109230