Exploring the Taste of Electronic Cigarettes - Aerosol Chapter (2)

Summary:
This article discusses the basic parameters of electronic smoke aerosols, such as particle size and distribution, as well as the movement and deposition characteristics of aerosols in smoking utensils and respiratory tract. The particle size distribution is usually described by D10, D50, and D90, where D50 represents the median particle size. The movement of aerosols is related to factors such as environmental temperature and gas flow rate, while their deposition in the respiratory tract is closely related to particle size. The particle size of electronic cigarettes is mostly within 1 μ Below m, the suction method (lung suction or oral suction) can also affect the sedimentation and detoxification effects of particles.
In the previous issue, we learned about the formation, evolution, and transport mechanism of aerosols, as well as the composition of electronic smoke aerosols. In this issue, we will introduce the basic parameters of aerosols and their movement and deposition characteristics in smoking utensils and respiratory tract.
Topic 2 Basic Parameters and Motion Sedimentation Characteristics of Aerosols
(1) Basic parameters of aerosols
Particle size: The size of aerosol particles, also known as particle size, is a general term for particle size and distribution;
Particle size distribution: refers to the proportion of particles with different sizes in a certain particle group, also known as dispersion;
D10, D50, and D90: The particle size distribution is generally described by the particle size distribution curve, where D represents the particle diameter. D10, D50, and D90 represent the particle sizes with a cumulative distribution of 10%, 50%, and 90%, respectively. D50 is also known as the median particle size. Figure 1 shows the particle size distribution curve of a certain atomizer, D50=0.756 μ m. Indicating that among all particle sizes, particles greater than and less than 0.756 μ The particles of m each account for 50%.
(2) The Movement and Sedimentary Characteristics of Aerosols
The movement of aerosols inside smoking utensils:
The atomized liquid particles generated by the atomization surface meet with room temperature air with a certain velocity, forming aerosols that enter the user's mouth through the airway. Figure 2 is a schematic diagram of the internal aerosol movement in a ceramic core atomizer. The state changes of aerosols during transportation are related to environmental temperature, gas flow rate, wall material, and roughness.
Deposition of aerosols in the respiratory tract:
The deposition pattern and particle size of aerosols in the human respiratory system are closely related to the particles inhaled in the atmosphere.
For electronic cigarettes, the particle size is mostly concentrated in 1 μ Below m, the suction method has a significant impact on the deposition of particles. During lung aspiration, aerosols pass through the mouth at a faster speed, with some particles depositing in the throat, forming a sensation of throat impact. The remaining particles directly enter the lungs and are eliminated through the respiratory tract after gas exchange. At this time, the concentration of aerosols has significantly decreased compared to inhalation, and the impact on nasal and oral receptors is weakened, which may reduce the perception of sweetness, aroma, and coolness; When inhaling, aerosols stay in the oral and nasal cavities for a longer period of time and have a stronger impact on the receptors on the tongue and nasal cavity, resulting in a more pronounced perception of the sweet aroma; In addition, compared to oral inhalation, lung inhalation has a more complete exchange of nicotine with the blood, making it more effective in relieving addiction. The introduction of smoking methods can refer to the sensory evaluation guide for electronic cigarettes (1): Evaluation methods