Global Warming & Air Quality: Impact on Airways

Global Warming Could Worsen Lung Disease by Inflaming Airways, Study Finds

New research highlights the dangers of increased air dryness and its potential impact on respiratory health.

April 2025

the Link Between Climate Change and Respiratory Health

As global temperatures continue to rise, a concerning trend is emerging, linking climate change to the exacerbation of lung diseases. A recent study featured in Nature Communications Earth & Habitat sheds light on how warmer, drier air can considerably impact respiratory health, perhaps worsening conditions such as asthma and COPD.

The research, led by David A. Edwards, MD, at John Hopkins, with significant contributions from Brian Button, PhD, professor of Biochemistry and Biophysics at the UNC School of Medicine’s Marsico Lung Institute, and Alessandra Livraghi-Butrico, PhD, associate professor in the Department of Medicine, explores the impact of high vapor pressure deficit (VPD) on human airways. VPD, a measure of air dryness, is increasing due to global warming, leading to a rise in water evaporation and potentially harmful effects on the lungs.

“This isn’t just a lab experiment — it’s a glimpse into how breathing hotter and drier air can result in more asthma flare-ups, worse allergies, and tougher breathing for millions of individuals,”

Brian Button, PhD, UNC Marsico lung Institute

for U.S. residents, particularly those in urban and rural areas, the implications are significant.Climate models project that by 2060-2099 summer conditions could push VPD to levels where the air struggles to saturate with water, heightening the risk of respiratory issues.

How dry Air Inflames Airways: The Science behind the Study

The study introduces a novel mechanism explaining how elevated VPD affects airway epithelial cells.Researchers discovered that airway mucus, a crucial protective layer, undergoes a process called transpiration – similar to water loss in plants. High VPD causes water to evaporate from this mucus layer, concentrating mucins and forming a denser gel.

This process, modeled mathematically by Drs. Edwards and Chung, thins the mucus and compresses the epithelial cells. This compression acts as a trigger, stimulating inflammation within the airways. Imagine a drought affecting your lawn; the grass becomes brittle and easily damaged.Similarly,dry air weakens the protective barrier in your lungs,making them more susceptible to inflammation and irritation.

Experimental evidence supported this theory. In experiments led by Dr. Button, human bronchial epithelial (HBE) cells exposed to dry air exhibited thinner, more concentrated mucus. Furthermore, these cells secreted high levels of cytokines, indicators of airway inflammation. These findings align with the theoretical predictions that mucus thinning in dry environments can produce sufficient cellular compression to trigger inflammation.

To further validate these findings, Dr. Livraghi-Butrico conducted studies using mice with defective airway mucus clearance. When exposed to intermittent dry air,these mice exhibited increased lung inflammation compared to those breathing standard room air. These in vivo results underscore the critical link between airway dehydration and worsening lung health in susceptible individuals.

This research highlights a critical public health concern and suggests a need for proactive measures. In the United States,where respiratory conditions like asthma and COPD are prevalent,strategies to maintain airway hydration could be crucial in mitigating the effects of climate change on respiratory health.

The Role of Mouth Breathing and Indoor Air Quality

The study also emphasizes the impact of mouth breathing. The increasing prevalence of chronic mouth breathing, frequently enough linked to obesity, allergic rhinitis, and aging, exacerbates the effects of dry air on the airways.When breathing through the mouth,air bypasses the nasal passages,which naturally humidify the air before it reaches the lungs. This leads to further dehydration and inflammation.

Moreover, the research raises concerns about the impact of prolonged exposure to air-conditioned and heated indoor air. While these systems provide comfort, they often reduce humidity levels, creating environments that can dry out the airways. This is particularly relevant in the U.S., where many peopel spend a significant amount of time indoors, whether at home, in the office, or in other enclosed spaces.

Consider the typical American office building during the winter. The heating system pumps out warm,dry air,creating an environment that can irritate the airways and exacerbate respiratory symptoms.Similarly, air conditioning during the summer can have a similar effect, removing moisture from the air and contributing to airway dehydration.

practical Implications and Potential Solutions

The findings of this study have significant implications for public health and offer potential avenues for intervention. The researchers suggest that maintaining airway hydration is a critical priority. This can be achieved through several strategies:

• Humidification: Using humidifiers in homes and workplaces can help increase the moisture content of the air, reducing the risk of airway dehydration.
• Nasal Breathing: Encouraging nasal breathing, especially during physical activity and sleep, can definitely help humidify the air before it reaches the lungs.
• Hydration: Staying adequately hydrated by drinking plenty of water can definitely help maintain overall moisture levels, including in the airways.
• Targeted Therapies: Further research could lead to the advancement of targeted therapies that specifically address airway dehydration and inflammation.

“This research underscores the urgent need to address airway hydration as a public health priority, suggesting that without intervention, millions could face heightened risks of chronic respiratory diseases by century’s end, while opening doors to new protective measures like enhanced humidity control or targeted therapies,”

Brian Button, PhD, UNC Marsico Lung Institute

The potential impact of these interventions is significant. By prioritizing airway hydration, we can potentially mitigate the harmful effects of climate change on respiratory health and improve the quality of life for millions of americans.

looking Ahead: future Research and Public Health Strategies

While this study provides valuable insights into the link between climate change and respiratory health, further research is needed to fully understand the complex interactions involved. Specifically, future studies could focus on:

• Identifying individuals who are most susceptible to airway dehydration and inflammation.
• Developing personalized strategies for maintaining airway hydration based on individual needs and environmental conditions.
• Evaluating the effectiveness of diffrent interventions, such as humidifiers and nasal breathing exercises, in preventing respiratory exacerbations.

Ultimately, addressing the impact of climate change on respiratory health requires a multi-faceted approach that combines individual actions with public health initiatives. By working together, we can create a healthier future for all Americans.

“This is the tip of the iceberg,”

Alessandra Livraghi-Butrico, PhD, UNC School of Medicine

Livraghi-Butrico adds, “In our line of research we cannot change the trajectory of climate change. Though, we can work on effective measures to prevent the exacerbations that these changes are causing. That’s where our job gets the most rewarding,when our research can contribute to people living healthier lives,and in this case,breathe better.”

This research was supported by NIH grants R01HL125280, P01HL164320, and P30DK065988.