Measurements of the Size and Composition of Volatile Particles Generated from a Heated Tobacco Product with Aerosol Fixation Agents

摘要

Accurate measurements of the particle size distribution and chemical composition of particles are important to understanding their influence on human health and the indoor environment. In this research, volatile particles generated from a pod-type Heated Tobacco Product (HTP) were measured with an Aerodyne Aerosol Mass Spectrometer (AMS) and Scanning Mobility Particle Sizer (SMPS) using various aerosol fixation agents to reduce the volatility of the particles. A simple method of aerosol fixation was applied, and the effective fixation agents and the primary factor of fixation were elucidated. The effectiveness of a fixation agent was determined based on the solubility between the aerosol substrates and the agent. Although nonadecanoic acid did not work for aerosol substrates with a low polarity, we found that it achieved greater success in fixing propylene glycol and glycerin. For particles that remained unfixed, the organic mass concentration (derived by AMS) was significantly reduced due to volatilization in the measurement apparatus. By contrast, the fixed volatile particles showed a higher organic mass concentration due to the suppression of volatilization. The peak number diameter of the unfixed volatile particles derived by SMPS was observed to be below 100 nm, whereas that of the fixed volatile particles was about 200 nm. The particle concentration of SMPS with fixation was in agreement with that of a light scattering method (welas~(?)). The elemental and surface compositions of the fixed volatile particles were analyzed by Scanning Electron Microscope-Energy Dispersive X-ray spectrometry (SEM-EDX) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) under vacuum conditions. The results revealed that the fixation agent was localized on the surface of the particles, reducing the volatility of the particles.