Effects of Common Alcohols on the Particle Size Distribution

of Atomized Aerosol in E-cigarette Vapour

WANG Shitai, JIN Yong, LI Ke, ZHAO Guoling PENG Xinhui, FAN

Hongmei, TAN Haifeng, LIU Jinyun, YU Saibo

Technology Center, China Tobacco Hunan Industrial Co.,Ltd.,

NO.426 Laodong Road, Changsha, Hunan, 410007, P.R. China

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Outline

1

2

3

4

Introduction

Method

Results and Conclusion

Summary

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Introduction :Background

◆ Electronic cigarettes (E-cigarettes) are perceived as a healthier alternative to

combustible tobacco products.

◆ Electronic cigarettes produce a condensation aerosol containing glycerol or propylene

glycol or mixture with water nicotine and flavor.

◆The dynamic qualities of the atomized aerosols present a considerable challenge for

measurement.

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Formation process of the aerosol

Introduction :Background

Different Similar

Conventional cigarette Burns tobacco leaves The same process from

vapor to aerosols

(vapor—aerosols)

Condensation

Unstable

High temperature

E-cigarette Heats the e-liquid

Low temperature

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Author Description

Laugesen et al.,2009 Count average particle size for e-cigarette aerosol less than

50nm(TSI3090 )mobility analyzer)

Schripp et al.2012

A predominant small diameter mode in the size distribution at about 50nm;a less

populated larger mode at around 100-200nm”(faster mobility particle sizer)

Ingebrethsen et al.,2012

particle size for e-cigarette aerosol at around 200-450nm(spectral transimission)

Zhang et al.,2013

Puffs generated peak particle counts at (VG) 180 nm and (PG) 120 nm. Steady-

state peaks occurred around 400 nm.”(SMPS)

Fuoco et al., 2014

Particle number distribution modes of the electronic cigarette –generated aerosol

were in the 120-165nm range, then similar to the conventional cigarette one.”

Vladimir B et al.,2016

A bimodal particle size distribution : nanoparticles (11-25nm count median

diameter) and submicron particles (96-175nm count median diameter)

Introduction: Published data(particle size )

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◆ WHY is it difficult to draw definitive conclusions from documents?

1. Obstacles to the measurement of particle size of high number concentration

aerosol containing volatile materials

2. Different methods and dilution ratio

3. The smoking regimes (puff profiles)

4. The compositions of the e-liquids were not described in detail

5. The voltage and other conditions of the e-cigarette device in experiments were

unclear.

Introduction

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Introduction

◆ The main objectives of this study was to measure the particle size distribution of

aerosol atomized by various alcohols and compositions of e-liquid under the same

atomization conditions known from e-cigarettes.

(1) The particle size of aerosol generated by various alcohols were determined under the

atomization conditions known from e-cigarettes ,respectively .

(2) The particle size distribution of atomized aerosol of e-liquid containing different

concentration of the propylene glycol and glycerol were studied.

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Aerosol from e-cigarettes was measured by electrical low pressure impactor (ELPI FINLAND)

Instrument & Method

The ELPI (Electrical Low Pressure Impactor) is a real-time

particle size spectrometer. The main components of the

instrument are a corona charger, low-pressure cascade impactor

and multi-channel electrometer.

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Instrument & Method

◆ Conditions: 1. The same volume e-liquid were added in atomizer.

2. Smoking profiles were square wave, 55 mL volume, 3s

duration at 30s intervals.

3. E-cigarette atomizer were used in experiment with the

same voltage and resistance.

4. The same dilution ratio.

E-cigarette atomizer

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Two carbon Three carbon Four carbon

One hydroxyl group CH3CH2OH

[Alcohol]

CH3CH2CH2OH [Propanol]

CH3CH2CH2CH2OH

[Butanol]

Two hydroxyl groups HOCH2CH2OH

[Ethylene glycol]

CH3CHOHCH2OH

[Propylene glycol]

HOCH2CH2CH2CH2OH

[1,2-Butanediol]

Three hydroxyl groups HOCH2(CH2O·CH2)CH2OH

[Glycerol]

HOCH2CH2CH(OH)CH2OH

[1,2,4-Butanetriol]

Many hydroxyl groups HOCH2[CH2O·CH2]mCH2OH

[Polyethylene glycol 200

(PEG200)]

HOCH2[CH2OCH2]nCH2OH

[Polyethylene glycol 400

(PEG400)]

◆ Molecular structure and formula:

Materials

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Results and Discussion

1. A single peak at around 0.02-0.05μm range.

2. Mostly particles in the 0.02-0.1μm range.

3. The peak value of number concentration of butanol is highest.

4. The number concentration of alcohol and propanol have not significant differences.

Material Boiling point℃

（101.3kPa）

Viscosity

（20℃）mPa·s

Butanol 117.5 2.9

Propanol 97.1 2.1

Alcohol 78.3 1.1

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◆The effect of alcohols on the size distribution(one hydroxyl group)

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Results and Discussion

1. A single peak at around 0.02-0.05μm range.

2. Mostly particles in the 0.02-0.1μm range.

3. The peak value of particle number concentration is the order:

1,2-butanediol>1,2-propanediol>ethylene glycol.

Material Boiling point℃

（101.3kPa）

Viscosity

（20℃）mPa·s

Butanediol 228.0 88.0

Propylene glycol 187.3 56.0

Ethylene glycol 197.3 16.5

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◆ The effect of alcohols on the size distribution(two hydroxyl groups)

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1. A double peak: one peak at 0.02-0.05μm and another peak at 0.1-1μm range .

2. The peak value of number concentration is higher at 0.1-1μm range.

3. The peak value of number concentration of butanetriol is lower than Glycerol at 0.02-

0.05μm. The peak value of number concentration of butanetriol is higher than Glycerol at 0.1-

1μm.

Results and Discussion

Material Boiling point℃

（101.3kPa）

Viscosity（25℃）

mPa·s

Butanetriol 312.0 1227

Glycerol 290.0 945

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◆ The effect of alcohols on the size distribution(three hydroxyl groups)

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Results and Discussion

1. A bimodal particle size distribution with one peak at 0.02-0.1μm and another peak at 0.1-

1μm.

2. The peak value of number concentration is higher at 0.1-1μm range.

3. The aerosol size distribution generated by PEG200 , PEG400 is different from low

molecule weight alcohols.

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◆ The effect of alcohols on the size distribution(many hydroxyl groups)

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Results and Discussion:

1. The number of large particles increase with increasing hydroxyl number .

2. The peak value of particle number concentration decrease with increasing hydroxyl number.

3. The relationship between the particle size distribution and molecular structure and properties.

Material Boiling point℃

（101.3kPa）

Viscosity（20℃）

mPa·s

Glycerol 290 1412

Propylene glycol 187.3 56.0

Propanol 97.1 2.1

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◆ The effect of alcohols on the size distribution(three carbon chain )

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Results and Discussion

1. The number of large particles increase with increasing hydroxyl number .

2. The peak value of particle number concentration decrease with increasing hydroxyl number.

3. The relationship between the particle size distribution with molecular structure and

properties(viscosity).

Material Boiling

point℃(101.3kPa)

Viscosity

(20℃)mPa·s

Butanetriol 312 1227(25℃)

Butanediol 228.0 88.0

Butanol 117.5 3.0

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◆ The effect of alcohols on the size distribution(four carbon chain)

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◆ The effect of the concentration of the propylene glycol and glycerol in

Solvent on the particle size distribution

Tab.1 the concentration of the propylene glycol and glycerol in Solvent

Glycerol% Propylene glycol% Tobacco extracts %

Solvent 1 10 88 2

Solvent 2 27 71 2

Solvent 3 45 43 2

Solvent 4 60 38 2

Solvent 5 70 28 2

Solvent 6 88 10 2

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Results and Discussion

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Results and Discussion

1. The peak value of number concentration increase at 0.02-0.05 range and decrease at 0.1-1

range with the proportion of glycerol decrease and propylene glycol increase in solvent.

2. The relationship between the particle size distribution and concentration of the propylene

glycol and glycerol.

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◆ The effect of the concentration of the propylene glycol and glycerol in

solvent on the particle size distribution

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Summary

1. The molecular structure and physical properties of alcohols in e-liquid are the factor

influencing the aerosol particle size distribution of e-cigarette vapor.

2. As the boiling point and viscosity increases , the number of large particles

increases.

3. With the increase of glycerol and the decrease of propylene glycol in the e-liquid,

the number of large particles in atomized aerosol increase, while the number of

small particles and the particle number concentration in aerosol decreased.

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Thank you for your attention!

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