Summary
Introduction:
This text provides an overview of the respiratory tract deposition of electronic cigarette (E-cig) particles, which is important for predicting the toxicity associated with vaping. The deposition of E-cig particles in the respiratory tract depends on particle size and breathing pattern, and understanding these factors is crucial for assessing the potential health risks of E-cig use.
Key Points:
* E-cig particle sizes range from 0.2 to 1.2 μm in mass median aerodynamic diameter (MMaD) and include an additional mode of ultrafine particles (<0.1 μm) in count median diameter (CMD).
* The mass median aerodynamic diameter (MMaD) of E-cig particles is typically in the range of 0.2 to 1.2 μm, while the count median diameter (CMD) likely includes an additional mode of ultrafine particles (<0.1 μm).
* The MPPD (Multiple-Path Particle Dosimetry) model predicts 10% to 45% total lung deposition by mass and 30% to 80% for ultrafine particles depending on the breathing patterns.
* The greatest fraction of inhaled E-cig particles is exhaled without depositing, but of those that deposit, most are in the alveolar region of the lung.
* The smaller MMaDs and CMDs of E-cig particles may be due to greater evaporation with the addition of higher room air flow for NGI (Next Generation Pharmaceutical Impactor) sampling.
* The dynamic properties of E-cig aerosols, such as volatility and hygroscopicity, may affect particle size distribution and deposition in the respiratory tract.
* There is a paucity of data on breathing and puffing patterns associated with a large variety of devices and inter-individual habits, and new methods for measuring the range of profiles associated with the variety of E-cig use may better predict dosimetry.
Main Message:
Understanding the respiratory tract deposition of E-cig particles is crucial for assessing the potential health risks associated with vaping. The particle size and breathing pattern of E-cig use are key factors that determine deposition in the respiratory tract, and accurate measurement of these factors is essential for predicting toxicity. While there is limited data on breathing and puffing patterns associated with E-cig use, new methods for measuring these patterns may improve deposition predictions. additionally, the dynamic properties of E-cig aerosols, such as volatility and hygroscopicity, may also affect particle size distribution and deposition in the respiratory tract. Overall, a more comprehensive understanding of E-cig particle deposition in the respiratory tract is necessary for assessing the potential health risks associated with vaping.
Citation
Bennett WD, Clapp PW, holbrook LT, Zeman KL. Respiratory Tract Deposition of E-Cigarette Particles. Comprehensive Physiology. 2022;12(4):3823-3832. doi:10.1002/cphy.c210038
