United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-98/080 August 1998
Project Summary
Indoor Air Emissions from
Office Equipment: Test Method
Development and Pollution
Prevention Opportunities
Coleen Northeim, Linda Sheldon, Don Whitaker, Bob Hetes, and Jennifer
Calcagni
The report describes development
and evaluation of a large chamber test
method for measuring emissions from
dry-process photocopiers. Application
of the test method will lead to a better
understanding of emissions from of-
fice equipment and to the development
of lower emitting machines. Challenges
and complications encountered in de-
veloping and implementing the test
method include: heat generation, which
can cause large increases in chamber
temperature; finite paper supplies for
photocopiers, which limit test duration;
toner off-gassing between tests, or
toner carryover if different types of
toner are tested; varying power require-
ments that may require changes in
chamber electrical supply; and remote
starting of the machines, which is nec-
essary to maintain chamber integrity.
The test method was evaluated in
two phases. Phase I was a single labo-
ratory evaluation at Research Triangle
Institute (RTI) using four, mid-range,
dry-process photocopiers. Phase I re-
sults indicate that the test method pro-
vides acceptable performance for
characterizing emissions, adequately
identifies differences in emissions be-
tween machines both in compounds
emitted and their emission rates, and
is capable of measuring both intra- and
inter-machine variability in emissions.
For Phase I, the compounds with the
highest emission rates from the four
different machines tested are:
ethylbenzene (28,000 ug/hour), m,p-xy-
lenes (29,000 ug/hour), o-xylene (17,000
|jg/hour), 2-ethyl-1-hexanol (14,000 ug/
hour), and styrene (12,000 uxj/hour). Al-
though many of the same compounds
were detected in emissions from each
of the four photocopiers, the relative
contribution of individual compounds
varied considerably between machines,
with differences greater than an order
of magnitude for some compounds. The
toners appear to be the primary source
of organic emissions from the photo-
copiers.
To investigate whether all chambers
produce similar results, a four-labora-
tory, round-robin evaluation of the test
method was performed in Phase II. A
single, dry-process photocopier was
shipped in turn to each of four labora-
tories along with supplies (i.e., toner
and paper). Phase II results demon-
strate that the test method was used
successfully in the different chambers
to measure emissions and that differ-
ences in chamber design and construc-
tion appear to have minimal effect.
This Project Summary was developed
by the National Risk Management Re-
search Laboratory's Air Pollution Pre-
vention and Control Division, Research
Triangle Park, NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Emissions from office equipment include:
volatile organic compounds (VOCs), alde-
hydes/ketones, ozone, and particles. Ex-
posure to these chemicals can contribute
to health effects such as eye, nose, and
respiratory system irritation, and several
are listed as hazardous air pollutants un-
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der the Clean Air Act (e.g., styrene,
ethylbenzene, m,p-xylene, o-xylene, tolu-
ene, and formaldehyde).
In March 1994, a group of technical
advisors met to discuss research on pol-
lution prevention approaches for reducing
indoor air emissions from office equip-
ment and to solicit input on technical pri-
orities for the research. The technical
advisors strongly recommended that a test
method be developed that could be used
to evaluate emissions from office equip-
ment. It was felt that such a method is
needed to evaluate different equipment
types and to establish comparable baseline
emission data that could be used as a
starting point for the development of spe-
cific pollution prevention approaches. Con-
currently with the technical advisors
meeting, a literature search was conducted
to identify and review published informa-
tion on office equipment design; indoor air
emissions of ozone, particulates, and or-
ganics; and potential pollution prevention
approaches for reducing these emissions.
Based on the literature review and on
input provided by the technical advisors,
this research focused on development and
evaluation of a large chamber test method
for measuring emissions from dry-process
photocopiers. EPA's objective in develop-
ing the test method is to promote emis-
sion testing of office equipment by
manufacturers and others in order to in-
crease understanding of emissions and
encourage the development and manu-
facture of lower emitting equipment.
Overview of Test Method
Research Triangle Institute (RTI) and
EPA's Air Pollution Prevention and Con-
trol Division collaborated with several of-
fice equipment manufacturers to develop
the large chamber test method. It is based
on the experience of RTI and EPA in
product testing, a published American So-
ciety of Testing and Materials (ASTM) test
method, and existing test methods used
by the participating manufacturers of of-
fice equipment. The test method utilizes
large, flow-through dynamic chambers be-
cause they are generally applicable to all
types of equipment and can be used to
mimic typical use conditions found in an
office. Listed below are some unique con-
siderations that are incorporated into the
test method.
1. Chamber Size: The test chamber's
linear dimensions must be a mini-
mum of 1.4 times the dimensions of
the equipment tested in accordance
with typical industry testing proce-
dures.
2. Heat Generation: To account for heat
generation, a temperature range of
28.5 + 2.5° C and an air exchange
rate of 2 air changes per hour (ACH)
are specified. Relative humidity (RH)
within the chamber is to be main-
tained at 30-35%. (A RH of 35% at
31° C represents a mass of water
equivalent to 50% RH at 23° C.)
3. Limited Paper Supply: A finite paper
supply for copy machines limits test
duration. For this study, a paper sup-
ply of 2000 sheets was used for
each test.
4. Remote Starting: Remote starting of
the machines from outside of the
chamber is necessary to maintain
chamber integrity.
5. Toner Carryover: When testing
equipment that uses toner, a toner
depletion and replenishment proce-
dure is to be followed to avoid
carryover of the previous toner be-
tween tests. Without the toner deple-
tion/replenishment, toner from a new
cartridge may be diluted by the toner
still retained in the delivery system
or the "old" toner may off-gas be-
tween tests, affecting emission re-
sults.
The sequence of operations below was
performed for the testing. Appendix B of
the report presents a complete descrip-
tion of the test method.
1. Check out copier (by service repre-
sentative);
2. Perform toner depletion/replenish-
ment;
3. Collect background air samples from
empty chamber;
4. Place copier in chamber;
5. Power up copier, load paper, and
test remote start;
6. Equilibrate copier in chamber over-
night in idle mode (i.e., powered but
not copying);
7. Collect integrated chamber air
sample for the copier in the idle mode
for a total of the estimated copying
time plus a time period equal to 4 air
changes (i.e., for a chamber oper-
ating at 2 ACH, the total idle period
sample collection time is the copy-
ing time plus 120 minutes);
8. Collect integrated chamber air
sample during full copier operation
and continue for a post-copying time
period equal to 4 air changes (i.e.,
for a chamber operating at 2 ACH,
the total sample collection time is
the copying time plus 120 minutes);
and
9. Determine air exchange rate using
pulse injection of a tracer gas (e.g.,
carbon monoxide) during the test.
In this study, toner recommended by
the manufacturer and the same type of
paper (containing 25% recycled materi-
als) were used. A standard image, repre-
senting about 15% coverage of the paper,
was used to represent a typical maximum
image for copying. For the copiers evalu-
ated in this study, 2000 copies were pro-
duced for each test. Copying time for the
2000 sheets ranged, depending on the
machine, from 20 to 40 minutes, for a
total sample collection time of 140 to 160
minutes. Chamber air concentrations of
VOCs were determined using multisorbent
tubes analyzed by a gas chromatograph/
mass spectrometer (GC/MS). Aldehyde/
ketone samples were collected on 2,4-
dinitrophenylhydrazine (DNPH)-coated
silica gel cartridges and analyzed by high
performance liquid chromatography. At
RTI, ozone was monitored continuously
using a DASIBI monitor. Limited particle
measurements were made using a LAS-X
optical particle counter.
Evaluation of the Test Method
The test method was evaluated in two
phases: I) four, dry-process photocopiers
were evaluated in RTI's chamber; and II)
a round-robin evaluation of one dry-pro-
cess photocopier was done in four differ-
ent laboratories (including RTI). Results
of triplicate measurements made in Phase
I show that the test method provides ac-
ceptable performance for characterizing
emissions from copiers. Percent recovery
for calculated emission rates for standard
materials released into the chamber at
known rates was greater than 85%. Preci-
sion of replicate tests using both standard
emitters and copiers was good, with less
than 10% Relative Standard Deviation
(RSD).
The data were also analyzed to deter-
mine differences in emissions between the
four copiers (Table 1). Emissions of VOCs
were consistently lower for Copier 3, which
used a mono-component toner, than for
the three machines that used dual-com-
ponent toners (Copiers 1, 2, and 4). How-
ever, emission rates for many of the
aldehydes and ketones were higher for
Copier 3. Also, ozone levels for Copier 3
were higher than for the other three ma-
chines. The data show that, although the
same compounds were emitted from all
four machines, the emission rates of these
compounds varied considerably between
machines. For example, the emission rate
for ethylbenzene was 28,000 |ig/h for
Copier 1 and <50 |ig/h for Copier 3. Lim-
ited particulate data were collected for two
of the four machines tested. Results show
that operation of one of the machines
increased particulate levels to 30 times
chamber background levels for particles
smaller than 0.2 :m in diameter.
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Table 1. Estimated VOC, Aldehyde/Ketone, and Ozone Emission Rates from Four Copiers.
(|ig/h • copier)
Chemical
Copier 1
Copier 2
CopierS
Copier 4
ethylbenzene
m,p-xylene
styrene
o-xylene
propylbenzene
2-ethyl-1-hexanol
n-nonanal
formaldehyde
acetaldehyde
acetone
benzaldehyde
ozone
28,000
29,000
9,900
17,000
790
230
1,100
<500
710
2,000
1,800
3,000
2,400
6,100
12,000
4,500
2,100
14,000
3,600
2,600
960
<500
2,600
4,700
<50
100
300
<50
<50
130
2,000
2,200
1,200
2,800
<100
7,900
360
510
3,000
850
460
5,600
3,900
<500
<500
<100
3,800
1,300
To investigate whether all chambers pro-
duce similar results (results may vary due
to differences in sink effects, for example),
a round-robin evaluation of the test method
was performed in four U.S. laboratories
during Phase II. To establish a common
basis for comparison, a single, dry-pro-
cess photocopier was shipped to each
laboratory in turn along with supplies (i.e.,
toner and paper). The tests followed the
same methodology used in Phase I with
one exception: a procedure for toner deple-
tion/replenishment was developed for the
copier in the round-robin testing. As dis-
cussed above, without the depletion/re-
plenishment process, off-gassing from a
toner cartridge left in the copier for an
extended time period prior to testing (at
least 1 month for these tests) would affect
emissions during subsequent testing.
The round-robin evaluation demon-
strated that differences in chamber design
and construction had minimal effect on
results. Excluding problems with suspected
analytical bias observed from one of the
laboratories, measurement agreement be-
tween laboratories is excellent for VOCs,
with RSDs of less than 10% in most cases.
More variability was observed between
laboratories for aldehydes/ketones (RSD
of 20% for formaldehyde). Ozone emis-
sion rates between three of the laborato-
ries were consistent (RSD of 15%), but
emission rates measured at the fourth
laboratory were much higher. Particle mea-
surements were not a focus of the study
because of the complexity of generating
known masses of particles (which would
be required for method evaluation).
Conclusions and
Recommendations
Conclusions and recommendations are
included for both Phase I and Phase II.
Phase I
Results of Phase I testing provided valu-
able information on the performance of
the test method and the emissions char-
acteristics of dry-process photocopiers.
The large chamber test method devel-
oped as part of this project provides ac-
ceptable performance for characterizing
emissions from dry-process photocopy
machines. In general, precision was much
better for the emission rate measurements
in the print mode than in the idle mode,
where measured emission rates had much
lower values.
A standard test method for measuring
indoor air emissions from office equip-
ment can present numerous challenges
and complications. Specific considerations
identified and addressed during this study
are: heat generation, limited paper sup-
ply, power requirements, remote starting,
and toner depletion and replenishment.
Although many of the same compounds
tended to be detected in emissions from
each of the four photocopiers, the relative
contribution of individual compounds var-
ied considerably between machines, with
differences greater than an order of mag-
nitude for some compounds. The varia-
tion in compounds is most likely due to
different toner formulations and/or toner
manufacturing processes.
Many of the compounds detected in
this study (benzaldehyde, ethylbenzene,
nonanal, ozone, styrene, and xylenes) are
consistent with compounds identified in
the literature from photoimaging equip-
ment. Again, any variation in compounds
is most likely due to the different toner
formulations used for different machines.
The integrated sampling approach for
generating emission rate data was deter-
mined to be acceptable. Time-point
samples were evaluated for two machines.
However, it is more labor-intensive and
costly; thus, the need for collecting time-
point samples should be evaluated on a
case-by-case basis.
Toner headspace testing indicates that
increased temperatures result in increased
organic concentrations in the headspace
gas. Results from the toner headspace
analysis also indicate that there may be
some correlation between toner headspace
analysis and copier emissions; however,
more testing of this relationship is required
before any conclusions can be drawn.
Toner lot, manufacturing process, and
age (as measured by the amount of time
that a cartridge has been opened) have a
significant impact on organic emissions
during both headspace tests and copier
operation. Therefore, any organization
planning to conduct photocopier emission
tests or analyze emissions data needs to
consider and control for this variable.
Phase II
Results obtained from different cham-
ber facilities are comparable. The VOCs
reported to have the highest emission rates
by all of the participating laboratories are
ethylbenzene, o-, m-, p-xylenes, and sty-
rene. These are also the compounds with
the highest emission rates reported from
Phase I testing.
Excluding problems with analytical bias
as seen from one laboratory, agreement
between laboratories for VOC measure-
ments is excellent (RSD of less than 10%
in many cases). Aldehyde/ketone and
ozone emission rates are more variable.
Differences in chamber design and con-
struction at the different laboratories
seemed to have little effect on test re-
sults. However, an analytical bias was
identified at one of the laboratories based
on the analysis of duplicates at RTI.
Potential Pollution Prevention
Opportunities
Potential opportunities for reduced emis-
sions from office equipment, specifically,
dry-process photocopiers, were identified
from the literature, discussions with manu-
facturers, and tests conducted as part of
this research.
The use of charged roller systems de-
creases ozone emissions; however, the
charged roller system presently has copy
rate limitations. Therefore, it is recom-
mended that future research focus on in-
vestigating the application of this design
change to higher throughput machines.
Both the literature and laboratory test-
ing indicate that the greatest level of or-
ganic emissions from dry-process
photocopiers comes from the toner during
the operating mode. As a corollary, higher
temperatures were shown to result in
higher organic emissions during toner
headspace tests. Therefore, additional pol-
lution prevention research should focus
on the relationship between toner formu-
lation and the fusing process. Specifically,
this could include:
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investigating the relationship between
fusing temperature and time in con-
tact with the fusing rollers;
testing of designs that use only pres-
sure fusing;
evaluating specific differences be-
tween mono-versus dual-component
toners and the resulting differences
in emissions;
evaluating the effect of toner particle
size on toner transfer efficiency and
particulate emissions;
investigating methods for increasing
the life of the photosensitive drum
that would result in better transfer
efficiency;
• identifying options for toner reformu-
lation and the use of high purity raw
materials; and
• evaluating other toner/fuser combi-
nations, such as ultraviolet (UV)-cur-
ing technologies, that are being used
by other sectors of the printing in-
dustry.
This research indicates that emissions
can vary depending on the specific toner
manufacturing process. The extrusion pro-
cess for manufacturing toner should be
investigated further. As one measure for
ensuring that multimedia pollution preven-
tion is being achieved, specifications
should be refined to ensure consistent
and "clean" raw materials for the toner
manufacturing process.
Photocopier emissions have been
shown to increase between routine main-
tenance cycles. Therefore, development
of new equipment designs that require
less (or even no) maintenance but are still
able to operate with the lowest possible
emission rates could result in pollution
prevention benefits over the life of a copier.
C. Northeim, L Sheldon, D. Whitaker, B. Hetes, and J. Calcagni are with Research
Triangle Institute, P.O. Box 12194, Research Triangle Park, NC 27709.
Kelly W. Leovic is the EPA Project Officer (see below).
The complete report, entitled "Indoor Air Emissions from Office Equipment: Test Method
Development and Pollution Prevention Opportunities," (Order No. PB98-165137;
Cost: $36.00, subject to change) will be available only from
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at
Air Pollution Prevention and Control Division
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
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