ASHRAE Journal - August 2014 - 8

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Hazards of E-Cigarettes
I commend Bud Offermann for
addressing the important issue of airborne contaminant exposure from
e-cigarettes in June's IAQ column "The
Hazards of E-Cigarettes." His analyses
show that while manufacturers claim
that e-cigarettes only emit harmless
water vapor, they actually emit many
harmful chemicals, including some
that are carcinogenic. In addition, Mr.
Offermann's exposure assessment
shows that the chemical emissions from
e-cigarettes are substantial and the risk
to those not "vaping" cannot be controlled with ventilation.
Thus he concludes that
e-cigarettes must be regulated in the same manner as tobacco smoking,
i.e., prohibited indoors
and in public spaces. I
completely agree with
his conclusions, and
I would like to add
some additional arguments against the use of
e-cigarettes in shared
environments.
Two contaminants
exceed the concentrations of concern noted in the article
for indirect exposure: propylene glycol
by 23 times and nicotine by 5.4 times.
Some readers may think that adjusting
the analysis, e.g., by modeling e-cigs
without propylene glycol, using lower
emission rates, larger spaces, or fewer
"vapers," the problem can be managed
by increased dilution ventilation. This
would be the wrong take-away message.
The risk of exposure to contaminants
does not disappear at some magic number set by regulatory authorities. Risk
assessments often arrive at the "acceptable" level by compromise for a healthy
working population.
Risks may be unacceptably high for
the young, pregnant, elderly, ill or
otherwise vulnerable populations.
Furthermore, acceptable levels are
often a trade-off between the risk and
expected benefits; occupants who
receive no benefit from the contaminant get a one-sided trade: only the risk.
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Occupants who are not "vaping" are
often receiving higher concentrations of
emissions than the fully mixed roomwide average concentration would suggest. This is especially true if, as is often
the case, they are adjacent to or across
the table from the "vaper."
There is often a lack of data on health
effects of exposures to low-level concentrations of contaminants. Furthermore,
according to the EPA, tens of thousands
of chemicals are currently in commerce,
and hundreds more are introduced
every year. Since current chemical testing is expensive and
time consuming, only a
small fraction of chemicals have been fully
evaluated for potential
human health effects
("Chemical Toxicity
Databases," http://
tinyurl.com/qe8axa6).
As a result, we frequently consider only
contaminants that are
known to cause shortterm health effects
from exposures to high
concentrations. Mr.
Offermann points out this lack of data
concerning inhaled flavorants.
There is also little or no data on effects
that result from exposures to multiple
contaminants in combination. This can
underestimate risks since combinations
of pollutants can be more hazardous
than the sum of the pollutants separately. For instance, VOCs can react with
each other and with other chemicals to
sometimes form chemicals of greater
concern (Weschler and Shields, 1999.
"Indoor Ozone/Terpene Reactions as a
Source of Indoor Particles." Atmospheric
Environment 33: 2307 - 2318). This is yet
another reason to eliminate nonessential sources.
The primary goal for the health of
building occupants is to eliminate
nonessential sources of indoor pollution entirely, not to calculate acceptable levels and try to dilute to these
levels. Source control, i.e., eliminating
exposures entirely where possible and

Au g ust 2014

minimizing them when they can't be
eliminated, is widely recognized as the
most cost-effective and efficient means
of protecting occupant health and is a
basic principle of public and occupational health.
HVAC engineers do this by selecting
clean locations for outdoor air intakes,
filtering outdoor air, using local exhaust
systems (e.g., in kitchens, industrial
facilities and laboratories), maintaining
pressure differentials and controlling
humidity. Our partners in the built
environment assist us by using paint
without lead, insulation without asbestos, low-emissions building materials
and office equipment; by segregating
contaminants in limited areas (copy
and print rooms, for example); and
eliminating activities that generate pollutants, such as smoking or operating
combustion engines indoors.
Of course, there are contaminant
sources that cannot be eliminated
entirely: our exhaled breath, sweat,
our skin, and our clothing give off pollutants, but we are necessary parts of
the indoor environment. E-cigarettes
are not, and based on Bud Offermann's
exposure assessment, they pose significant risk. For this reason and the others
stated above, they should be banned
from public spaces and workplaces to
prevent unwitting and unwilling exposure to others.
Larry Schoen, P.E., Fellow ASHRAE, Columbia, Md.

The Author Responds
Mr. Schoen's proposed IAQ control
philosophy, "Don't add unnecessary pollutants to indoor air," which dispenses
with any engineering consideration of
the actual chemical exposures, certainly
begs the question, "Just what are these
unnecessary pollutants?" Whatever
these are, I am sure there would be
arguments regarding what constitutes
an "unnecessary" pollutant. It would
seem that an IAQ control philosophy
based upon a subjective determination
of "unnecessary pollutants" would likely
force us into a future of indoor environments where only those things deemed
"necessary" would be allowed with

ASHRAE Journal - August 2014

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