A chamber study of second-hand

E-cigarette “smoke” – a methodology and

some preliminary results Gordon McFiggans1 & Roy Harrison2

Rami Alfarra1, James Allan1, Jamie Whitehead1

David Beddows2 1. University of Manchester

2. University of Birmingham

g.mcfiggans@manchester.ac.uk; r.m.harrison@bham.ac.uk

PM is the most important contributor to Air Quality

COMEAP, 20101 estimated 340,000 years of total survival time was lost to the current population across the UK in 2008

Speculated that 200,000 annual premature deaths attributable to air pollution higher than the 116,000 attributed to the combined effects of alcoholism, obesity

and smoking.

estimated cost of PM in the UK of €15K - €40K / emitted tonne in terms of mortality2

1. COMEAP, 2010, ISBN 978-0-85951-685-3

2. Revealing the costs of air pollution from industrial facilities in Europe, ISSN 1725-2237

Several different major atmospheric particle types

Primary

mechanical

(“dust”, pollen

etc.) Primary combustion

(“smoke”, “soot” etc.)

Secondary (natural

e.g. “smokey

mountains” or

manmade “smog”)

Volatile primary / secondary

(clouds, spray perfumes, air

fresheners etc…)

3m x 3m x 2m FEP Teflon bag

Simulated solar spectrum,

filtering to get rid of excess UV

Ultraclean dilution air (pptv level

of gaseous contaminants and

< 0.1 μg m-3 particles)

Photochemical chamber experiments

Inject individual chemicals as particle

precursors

…or real emission sources at real

atmospheric concentrations e.g. continuous

emission from tree saplings

…or exhaust sampled from diesel engine

sample with sensitive research-grade online

atmospheric instruments

10 x 5 second puffs diluted into 18 m-3

ultraclean air

Measure:

particle size

particle number

particle composition

their changes with time

…or active / passive e-cigarette or real cigarettes emissions

10 Puffs of E-Cigarette diluted into 18 m3 air, in the dark

1st Mode

2nd Mode

(near identical)

1st Mode 2nd Mode

(smaller)

Quite high numbers, small particles (40-70 nm), low mass concentration, simple

composition that doesn’t change much, evaporating and depositing with time

1st Mode

2nd Mode

Light only

Light & Ozone

Ozo

ne

in

jecte

d

Quite high numbers of small particles (40-60 nm), low mass concentration,

simple composition that oxidises moderately, low evaporation plus deposition

1st Mode 2nd Mode

10 Puffs of E-Cigarette diluted into 18 m3 air, light + O3

SP-AMS (composition of soot

containing particles)

AMS (composition of all

particles)

Moderately high numbers of larger (400 nm) sooty particles, much higher

mass concentration, complex composition (paraffinic, olefinic and aromatic)

that oxidises moderately, deposited but no evidence of evaporation

7 Puffs of Traditional Cigarette diluted in 18 m3 air, light + O3

Diesel Engine: 2000RPM, 40% load, Dilution 275:1 “roadside”,

with catalytic converter

SP-AMS (composition of soot

containing particles)

AMS (composition of all

particles)

High numbers of quite small (100 nm) sooty particles, moderate mass

concentration, complex composition (paraffinic and olefinic), deposited but

no evidence of evaporation

Secondary Organic Aerosol from 250 ppb Limonene

(levels reported in indoor environments)

Quite high numbers of large secondary particles (300 nm), high mass

concentration, moderately complex composition quite highly oxidised,

deposited but no evidence of evaporation

We can measure the size, number, composition, properties and

atmospheric changes to particles made from e-cigarettes

E-cigarettes produce fine particles that can persist but evaporate and

deposit with time

The particles are simple in composition that changes little with time in

the atmosphere

In comparison, traditional cigarette smoke is involatile, comprising larger

sooty particles with a complex organic matrix

E-cigarette particles are produced at low mass loading compared to

recognised sources of particle pollution such as diesel exhaust

Particle emissions from e-cigarettes should also be set in context of

those made in the indoor atmosphere from some household products

such as cleaning materials

We have the capability to cover a much wider range of measurements of

all properties of interest. These are illustrative first findings.

Summary

1. Particle mass concentration

Size of chamber, versus size of small room:

18 m3 versus 30 m3

Mass concentrations of particulate matter in chamber are

stable initially at about 4 µg m-3 from 10 puffs if all smoke

were exhaled; likely to be much lower under “normal” usage

Implies a concentration increase in the chamber of around

0.4 µg m-3 per puff, or around 0.2 µg m-3 per puff in a small

room

If 5 vapers each generate 5 puffs per minute for 10 minutes,

the implied concentration is 50 µg m-3

Compares with an urban PM2.5 concentration in UK cities of

ca. 15 µg m-3, and a WHO guideline for PM2.5 of 25 µg m-3

(24-hour average) or 10 µg m-3 (annual mean)

What do the chamber data imply for public health?

2. Particle number concentration

Particle number is a measure of the nanoparticles present.

There is some evidence that these are more toxic per unit mass

than larger particles

The most recent epidemiology from London (Atkinson et al.,

2010) showed a statistically significant association between

particle number concentration and cardiovascular mortality

Initial particle count in the chamber was 20 x 103 particles/cc,

from equivalent to 10 puffs directly exhaled; likely to be much

lower under “normal” usage

Implies a concentration increase in the chamber of around 2 x

103 particles/cc per puff, or around 1 x 103 per puff in a small

room

If 5 vapers each generate 5 puffs per minute for 10 minutes, the

implied concentration is 250 x 103 particles per cc

Compares with a typical urban concentration of around 10 x 103

particles per cc, and exceeds concentrations measured

alongside busy roads

What do the chamber data imply for public health?

CONCLUSIONS

The data are preliminary and need to be repeated and

extended

The preliminary data provide evidence for a possible

exposure risk to passive smokers in enclosed spaces with

no ventilation if all the emissions from e-cigarettes were

exhaled

Particle mass concentrations are about 100-fold lower than

from conventional cigarettes, but particle number

concentrations are similar if directly exhaled

Health risks are likely to be smaller than those associated

with conventional cigarettes

Further measurements, especially for nanoparticle number

concentrations, are strongly recommended

What do the chamber data imply for public health?