Today I learned that lymph nodes are heavily impacted by air pollution. This photo shows lymph nodes specifically associated with the lungs and how they are affected by air pollution as we age. It’s gruesome. I already knew fine particulates were bad, but this image has visceral impact and I’ll strengthen the advice I give to clients about how to reduce PM2.5 particles inside their buildings.
I have US building scientist Allison Bailes to thank for alerting me to this research. His blog post on this issue refers to a scientific paper published in Nature Medicine in 2022. (That’s his caption and citation in the image above.)
For a long time, I’ve been advising clients to avoid installing or using gas cooking appliances indoors and to install proper F7 filters in their ventilation systems. Those are the most important ways to reduce PM2.5 particulate levels indoors. Now I’ll be waving these images at them.
This photo, from the same research, shows lymph nodes associated with the lungs on the left and those associated with the stomach on the right, at different ages. Big difference.
The editorial team at Nature Medicine had this to say about the significance of the research: ““This work … stood out because it examined the effects of age on human immune system function using [lymph node] samples, rather than blood samples as is common, and because it offered new insight into how environmental pollutants may alter immune activity. The results will hopefully motivate further research into how carbon emissions and other forms of pollution affect immune responses.” Emphasis mine.
The full paper is currently freely available to read online:
Effect of air pollution on the human immune system.
Nat Med 28, 2482–2483 (2022).