May 29, 2024 03:54 PM
https://www.acsh.org/news/2024/05/28/eve...ungs-17835
INTRO: In an invisible dance, micro and nanoplastics move about, ubiquitous yet unnoticed. These minuscule particles bob and weave into every corner of our existence. Yet, their impact on our respiratory health is unclear. How do these particles navigate the pathways of our respiratory tree, and what does this mean for our well-being?
EXCERPT: The lungs are asymmetric, the right side having three lobes, the left two (one “displaced” by the presence of the heart). The main stem bronchi, the first division of the lungs to left and right, differ with the right main stem bronchus, which is shorter, straighter, and wider. Larger particles settle to the left, smaller to the right.
Size matters, with larger particles settling in the upper airways along the front of the nasal cavity and throat (larynx). Smaller particles distribute more evenly and deeply.
The respiratory rate also influences distribution. Faster rates favor inertia and gravity, depositing more of those larger particles in the upper airways. Slower rates favor diffusion, depositing smaller particles evenly enhancing asymmetries.
Slower breathing facilitates longer and deeper transportation.
The throat and mid-level bronchi are the deposition hotspots.
Particulate shape also plays a role. Cylindrical particles align with airflow and avoid mucus and other filtration methods but tend to deposit in the upper respiratory tract. Tetrahedral shapes tumble about with the edges catching on division points in the bronchial tree (bifurcations), enhancing their deposition in these areas. Additionally, their smaller size increases a more dispersed distribution.
The escape fraction (EF) is the proportion of inhaled particles that escape upon exhalation. Smaller particles have a greater EF, as does increasing respiratory rates. Particles deposited in the upper airways have a greater EF, as do spherical particles over other shapes.
The deposition fraction (DF) is those inhaled particles staying put. Slow breathing, with increased deposition in the nose and throat, increases DF. Faster breathing moves deposits deeper but in smaller amounts, a lower DF... (MORE - missing details)
INTRO: In an invisible dance, micro and nanoplastics move about, ubiquitous yet unnoticed. These minuscule particles bob and weave into every corner of our existence. Yet, their impact on our respiratory health is unclear. How do these particles navigate the pathways of our respiratory tree, and what does this mean for our well-being?
EXCERPT: The lungs are asymmetric, the right side having three lobes, the left two (one “displaced” by the presence of the heart). The main stem bronchi, the first division of the lungs to left and right, differ with the right main stem bronchus, which is shorter, straighter, and wider. Larger particles settle to the left, smaller to the right.
Size matters, with larger particles settling in the upper airways along the front of the nasal cavity and throat (larynx). Smaller particles distribute more evenly and deeply.
The respiratory rate also influences distribution. Faster rates favor inertia and gravity, depositing more of those larger particles in the upper airways. Slower rates favor diffusion, depositing smaller particles evenly enhancing asymmetries.
Slower breathing facilitates longer and deeper transportation.
The throat and mid-level bronchi are the deposition hotspots.
Particulate shape also plays a role. Cylindrical particles align with airflow and avoid mucus and other filtration methods but tend to deposit in the upper respiratory tract. Tetrahedral shapes tumble about with the edges catching on division points in the bronchial tree (bifurcations), enhancing their deposition in these areas. Additionally, their smaller size increases a more dispersed distribution.
The escape fraction (EF) is the proportion of inhaled particles that escape upon exhalation. Smaller particles have a greater EF, as does increasing respiratory rates. Particles deposited in the upper airways have a greater EF, as do spherical particles over other shapes.
The deposition fraction (DF) is those inhaled particles staying put. Slow breathing, with increased deposition in the nose and throat, increases DF. Faster breathing moves deposits deeper but in smaller amounts, a lower DF... (MORE - missing details)