Fig 1.
Experimental setup for diluting and sampling EC and cigarette aerosol.
a.) Static dilution process of conducting a 60mL puff into a 100mL glass syringe, conducting a 1:10 syringe dilution then 1:28 dilution by injecting into a Tedlar bag for aerosol sampling. b.) System for dynamic dilution and characterization of aerosol by SMPS and APS simultaneously. Unique dilution rates were applied to SMPS and APS to achieve aerosol concentrations within single particle counting ranges. MFC—mass flow controller, HEPA—high efficiency particulate air.
Fig 2.
Vaporization rate per puff of a G2 EC atomizer with total resistance of 3.02Ω.
Vaporization rate per puff of a 3.02Ω single coil EC atomizer was measured by weight difference across a 10 puff series with 30 seconds between puffs at 9 wattages. EC atomizer was powered by a laboratory power supply for these experiments. Each point is the average vaporization per puff with standard error bars.
Fig 3.
Particle size and mass distributions for EC aerosols and tobacco smoke.
a.) EC aerosols produced by a 2nd generation EC atomizer powered by a laboratory power supply at 9 different levels. Nano-sized particle count decreased as power increased but micron sized particles increased as power increased. b.) Mass distribution of EC aerosol calculated from particle size distribution. Large particles make up the majority of aerosol mass. c.) EC aerosols produced by the same atomizer powered by a variable voltage EC battery at Vmin and Vmax dial settings and compared to a Kool Blue cigarette smoke aerosol. Note the distinct difference between EC aerosol and cigarette smoke. Data shown are average of three trials. d.) Mass distribution of EC aerosol and cigarette smoke calculated from particle size distribution. Battery powered EC aerosol has a smaller particle mode around 1 μm than observed in power supply experiments which may be due to battery underperformance. Data shown are average of three trials.
Fig 4.
Cumulative mass fraction by size for EC aerosol and cigarette smoke.
a.) EC aerosol generated with laboratory power supply at 9 levels. As power increases, a greater fraction of the mass is below 4 μm which is within the respirable fraction, left of the vertical line. b.) Cigarette smoke (Kool Blue) and EC aerosol powered by a variable voltage EC battery at Vmin and Vmax dial settings. Respirable fraction of cigarette smoke and EC aerosol at minimum dial setting are very similar. Respirable fraction does not increase as greatly when powered by battery compared to laboratory power supply, this may be due to battery underperformance.