Dry air danger for lungs identified

Scientists from the US National Institutes of Health have discovered that dry air can cause dehydration and inflammation of the respiratory tract. The work is published in the journal Communications Earth & Environment (CEE).

Researchers have found that as the Earth's average temperature rises, relative humidity remains at the same level, but the vapor pressure deficit (VPD) - an indicator of how "thirsty" the surrounding air is for water - is rapidly increasing. High VPD increases the rate of water evaporation, causing dehydration of both natural ecosystems and human respiratory tracts.

During the study, the team of scientists examined the effects of dry air on human bronchial epithelial cells. After exposure to dry air, the cells showed thinning of the mucous layer and high levels of cytokines - proteins indicating inflammation. These results are consistent with theoretical predictions that dry air causes dehydration and inflammation of respiratory tract cells.

Animal experiments confirmed these findings: mice exposed to dry air for a week showed signs of inflammation in the lungs, while mice breathing humid air did not have such reactions. Inflammation was particularly severe in mice predisposed to respiratory tract dryness, which is characteristic of chronic respiratory diseases.

Scientists predict that by the middle of the 21st century, most of the United States will be at increased risk of respiratory inflammation due to rising temperatures and decreasing air humidity. This may also lead to an increase in diseases associated with dry mucous membranes, such as chronic cough, allergic rhinitis, and asthma.

"This discovery changes our understanding of medicine. Dehydration of mucous membranes already poses a serious threat to human health, and in the future, this problem will only worsen due to global warming," says Justin Hanes, a professor of ophthalmology at the Wilmer Eye Institute at Johns Hopkins University and co-author of the study.

The results of the study raise the question of the need for new methods to protect the respiratory tract and mucous membranes from dehydration. Scientists believe that lifestyle adjustments, the use of air humidifiers, and the development of therapeutic solutions will help reduce the negative impact of dry air on health.