United States Environmental
Protection Agency
Office of Research and Development
Research Triangle Park, NC 27711
a EPA
EPA/600/N-96-002 Spring/Summer 1996
Inside I A Q
EPA's Indoor Air Quality Research Update
Engineering Solutions to
Indoor Air Quality Problems
Symposium
July 21-23, 1997
Research Triangle Park, NC
(See Page 12 for Call for Papers)
In This Issue Page
lEMB's Large Chamber 1
Effects of HVAC Fan Cycling on the
Performance of Particulate Air Filters . . 2
Reducing Indoor Air Emissions from
Engineered Wood Products 5
Cost-Effectiveness of Alternative
IAQ Control Techniques 6
Quality Assurance for EPA's IAQ
Research 7
Emissions of Carbonyl Compounds
from Latex Paint 8
Glossary of Acronyms 8
Summaries of Recent Publications 9
Contacts in IEMB 11
Inside IAQ is distributed twice a year by the
Office of Research and Development's
National Risk Management Research
Laboratory's (NRMRL) Air Pollution
Prevention and Control Division (APPCD).
Indoor air quality (IAQ) research conducted by
APPCD's Indoor Environment Management
Branch (IEMB) is highlighted. If you would
like to be added to or removed from the
mailing list, please mail, fax, or e-mail your
name and address to:
Inside IAQ, Attn. Kelly Leovic
U.S. EPA (MD-54)
Research Triangle Park, NC 27711
Fax: 919-541-2157
E-mail: kleovic@engineer.aeerl.epa.gov
lEMB's LARGE CHAMBER
IEMB has designed and installed a state-of-the-art large chamber in their
Research Triangle Park Facility. The room-sized (30-m3) stainless steel test
chamber and sophisticated analytical instrumentation will permit
characterization of emissions from products and processes that cannot
readily be studied using small chambers. The new facility will enable
researchers to study, under highly controlled environmental conditions,
indoor pollution episodes such as interior painting and use of other
consumer products that impact IAQ. These types of processes often result
in high initial personal exposures and also load other surfaces (i.e., sinks)
such as carpets, wall coverings, and ceiling tiles with pollutants that may be
re-emitted to the indoor air over a long period of time.
The test chamber's versatile air distribution system (Figure 1) permits
researchers to simulate home or office air distribution patterns and test
in-room and in-duct air cleaning devices. System design permits single
pass, partial, or complete recirculation of highly filtered air that is
supplied to the chamber through glass ducting. Chamber temperature, air
exchange rate, relative humidity (RH), and pressure are automatically
set and controlled by a computer.
Many of the basic elements of the large chamber design have been
incorporated into large chambers constructed in Canada and Australia.
Initial experiments conducted in the large chamber will include tests to
evaluate the performance of EPA's chamber and determine
comparability with these other chambers. Future collaborative research
will be directed toward development and validation of test methods and
indoor air models as well as investigation of important sources and
control strategies.
Currently, IEMB is conducting tests to fine tune the chamber. Tests that
are underway are designed to evaluate critical factors that may influence
experiments. These tests are designed to evaluate the 1) ability of the
chamber control system to maintain a wide variety of temperature and
RH set points; 2) air velocities within the chamber at different flow
conditions; 3) mixing of pollutants at low, elevated, and normal
temperatures and at high and low air flow rates; and 4) adsorption of
volatile organic compounds (VOCs) by chamber walls, air duct walls,
and components of the air-conditioning system.
(Continued on Page 2)
-------
EXHAUST TO OUTDOORS
MAX. 700 CFM
1 CUBIC FOOT/MINUTE fCFM) =
0.47 LITER/SECOND
MAX. 500 CFM
MIN.5CFM
Figure 1. Schematic of lEMB's Large Environmental
Chamber
Results indicate that the automated control system can
maintain temperatures over a range of 15 to 30 ° C with RHs
ranging from 30 to 70% when chamber air is recirculated
through the air-conditioning system. As expected, when the
chamber is operated in single pass, low flow mode, the
temperature inside the chamber varies with the air
temperature of the room housing the chamber. Mixing tests
indicate that pollutants introduced into the chamber mix
rapidly and do not appear to "short circuit" between the
inlets near the floor and the outlet in the ceiling. Chamber
wall loss tests have demonstrated insignificant to slight
adsorption of several typical indoor air contaminants when
the chamber is operated in single pass mode (no
recirculation of air through the chamber air-conditioning
system). These results indicate that wall effects in the large
chamber are very small compared to wall effects that have
been observed in small test chambers. Adsorption of low
volatility and polar compounds has been observed when
chamber air is recirculated through the air-conditioning
system. These effects are manageable and are not expected
to interfere with use of the chamber to characterize sources
and develop source management methods that result in
reduced exposure to indoor air pollutants. Future issues of
Inside IAQ will provide updates on tests conducted in the
chamber. (EPA Contacts: Mark Mason, 919-541-4835,
mmason@engineer. aeerl.epa.gov and Betsy Howard, 919-
541-7915, bhoward@ engineer.aeerl.epa.gov)
EFFECTS OF HVAC FAN CYCLING ON THE
PERFORMANCE OFPARTICULATE AIR FILTERS
Heating, ventilating, and air-conditioning (HVAC) system
components have been identified as potential emission
sources that may affect IAQ under some conditions (HVAC
Systems as Emission Sources Affecting Indoor Air Quality:
A Critical Review, EPA-600/R-95-014; NTIS PB95-
178596, February 1995). Emissions include dust, dirt, and
other airborne particles entrained from outdoor air (OA)
and from air recirculated from the occupied spaces. These
contaminants accumulate on HVAC surfaces including the
filtration systems. Dirty or loaded filters have been
associated with total particle and bioaerosol shedding as the
system fan cycles on and off.
Filters are installed in HVAC systems by design engineers
for two primary reasons: 1) protection of system
components (fans, motors, control devices, etc.) from the
degrading effects of dust and dirt, and 2) reduction of
occupant exposure to airborne particles and bioaerosols. It
has been suggested that dirty or loaded filters may be
associated with total particle and bioaerosol shedding as the
HVAC system fan cycles on and off.
IEMB and the University of Minnesota performed research
to determine the shedding contribution from loaded filters
(see Effects of Fan Cycling on the Performance of
Particulate Air Filters Used for IAQ Control on page 9).
Fiberglass and synthetic organic media bag filters were
tested using two laboratory test duct setups. Each test duct
was 2 by 2 ft (0.6 by 0.6 m). The blower fan, which was
cycled on and off, was configured as a draw-through system
that challenged the filters with 100% OA. Total airborne
particle counts were made with an optical particle counter,
and viable bioaerosol counts were obtained with a slit
impactor with a rotating plate. Filter surface microorganism
samples were obtained with growth plates. The two filters
tested were a fiberglass bag filter with a rated dust spot
efficiency of 85% and a synthetic organic media bag filter
with a rated dust spot efficiency of 65%. Both filters have
eight pleated pockets.
The filters were loaded with outdoor aerosols with the fan
running continuously except for the time when the fan
cycling data were obtained. Initial tests on clean filters
were inconclusive so the tests reported here were made after
the filters had been loaded for approximately 1 year.
(Continued on Page 3)
Inside IAQ, Spring/Summer 1996
Page 2
-------
Figures 2 and 3 illustrate typical total particle concen-
trations measured upstream and downstream from the
fiberglass filter when the fan was cycled off and on.
Figures 4 and 5 show the bioaerosol collected versus time
by the slit impactor downstream from the fiberglass filter
when the fan was cycled. Results from the synthetic organ-
ic filter are similar. Table 1 shows the results of a surface
sampling test using Inhibitory Mold Agar (IMA) growth
media.
Figure 2 shows that the particle concentration in the upstream
duct (i.e.,OA) does not change during the fan cycling. In some
of the runs, the concentration dropped when the fan was turned
off. However, the total concentration in these runs was much
higher than the values shown in Figure 2 and settling losses
were significantly higher.
The downstream concentration of particles in Figure 3
shows a trend found in most of the tests. When the fan is
turned off, the air velocity through the filter gradually
decreases as the fan wheel slows to a stop. Media filters
become more efficient when the velocity through them is
reduced as the particles have longer residence time to
diffuse to the filter media. Therefore, the particle
concentration downstream of the filter decreases shortly
after the fan is turned off. The fan discharges air through a
set of open dampers and a short duct section directly
outdoors. With the fan off, outdoor contaminants can
diffuse into the discharge duct. This causes the
concentrations on the downstream side of the filter to
increase. Note that the downstream concentration at
readings 10 and 11 on Figure 3 are still much lower than
the upstream levels shown in Figure 2. Long term tests
with the fan off indicated that the downstream
concentrations never reach upstream concentrations. This
is caused by settling and diffusion to surfaces between the
filter and outdoors. When the fan is restarted, the down-
stream particle concentrations rapidly return to the level
before the fan was stopped.
Results from one of the viable bioaerosol tests are shown in
Figures 4 and 5. Concentrations of colony forming units
(CPUs) are high immediately after the impactor is started
and the access door closed. This is caused by room air
entering the ductwork downstream of the filter because the
duct is at a negative pressure with respect to the room.
Particles may also be dislodged from the duct surfaces and
perhaps the filter when the door is closed. Shortly after the
door is closed, the downstream bioaerosol counts decrease
to nearly zero. The counts remain low during the fan
cycling. There are a few random counts but no repeatable
pattern of bioaerosol concentrations was observed.
(Continued on Page 4)
500,000
j, 400,000
°- 200,000
100,000
Ifan
turnec
off
I fan tur
ned on again
1 2 3 4 5 6 7
9 10 11 12 13 14 15 16 17 18 19 20 21
Readings
Figure 2. Total particle concentration versus time upstream
from the fiberglass filter (31 seconds between
successive readings) (1 ft3 = 28 L)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Readings
Figure 3. Total particle concentration versus time down-
stream from the fiberglass filter (31 seconds
between successive readings) (1 ft3 = 28 L)
30
25
20
15
10
5
n -
f duct access door
closed
I Fan turned off
I Fan turned on
Time span (seconds)
Figure 4. Total bioaerosol concentration versus time down-
stream from the fiberglass filter (IMA media)
(1 ft3 = 28 L)
duct access door
closed
Fan turned off
Fan turned on
lagain
Time span (seconds)
8 8
i §
Figure 5. Total bioaerosol concentration versus time down-
stream from the fiberglass filter (Standards
Method Agar media) (1 ft3 = 28 L)
Inside IAQ, Spring/Summer 1996
Page 3
-------
Table 1 shows the results of one of the surface sampling
tests for both the fiberglass and synthetic organic filters
using IMA media. The microbial counts upstream of the
filters are high on the filter surface and on the bottom
surface of the duct. Counts are lower on the side walls of
the duct. Downstream, the counts are very low almost
everywhere indicating good bioaerosol removal by both bag
filters.
In conclusion, no statistically significant particle shedding
from the bag filters was observed by either the optical
particle counter or the viable bioaerosol slit impactor when
the fan was cycled. These results are different from
previous research; however, the filter media and types may
have been different. When the fan was turned off, total
particle concentrations downstream of the filter decreased
initially followed by a marked increase. This can be
explained by an increase in filter capture efficiency at low
air velocity and by diffusion of outdoor particles into the
discharge ductwork when the fan was off. Surface samples
for viable fungi and bacteria generally indicated high levels
on the upstream sides of the filters and on the upstream duct
surfaces but very low counts downstream. (EPA Contact:
Russ Kulp, 919-541-7980, rkulp@engineer. aeerl.epa.gov)
Table 1. Surface Sampling Test Results (IMA Media)
Filter Type
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Fiberglass
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Synthetic Organic
Location
Upstream
Upstream
Upstream
Upstream
Upstream
Downstream
Downstream
Downstream
Downstream
Downstream
Upstream
Upstream
Upstream
Upstream
Upstream
Downstream
Downstream
Downstream
Downstream
Downstream
Sample
Bag 5, upper end
Bag 5, lower end
Side duct wall
Side duct wall (door)
Bottom duct wall
Bag 5, upper end
Bag 5, lower end
Side duct wall
Side duct wall (door)
Bottom duct wall
Bag 5, upper end
Bag 5, lower end
Side duct wall
Side duct wall (door)
Bottom duct wall
Bag 5, upper end
Bag 5, lower end
Side duct wall
Side duct wall (door)
Bottom duct wall
Results *
overgrowth
overgrowth
moderate growth
moderate growth
overgrowth
no growth
no growth
no growth
low growth
low growth
overgrowth
overgrowth
moderate growth
moderate growth
overgrowth
low growth
no growth
no growth
no growth
moderate growth
low growth
moderate growth
overgrowth
1-10 CPUs
11-30 CPUs
colonies merge together
Inside IAQ, Spring/Summer 1996
Page 4
-------
REDUCING INDOOR AIR EMISSIONS FROM
ENGINEERED WOOD PRODUCTS
Research over the past two decades has shown that
engineered wood products can be emission sources for
many organic compounds. Emissions can arise from the
engineered wood (both the wood and resin); finishing
materials applied to the engineered wood for decorative
purposes such as finished wood veneer, ink prints, and
paper overlays; and glues used to fasten pieces of finished
engineered wood together. Research Triangle Institute is
working cooperatively with IEMB to characterize indoor
emissions from engineered wood products and to identify
and evaluate pollution prevention approaches for their
manufacture that may reduce indoor emissions.
18,000
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
0
PBVST
HBVSST
PBVY
Figure 6.
PBVST = Veneered Particleboard with Sealer and Topcoat
HBVSST = Veneered Hardboard with Stain, Sealer, and Topcoat
PBVY = Particleboard with Vinyl
PBM = Particleboard with Melamine
Emission Rates of Total VOCs from Selected
Types of Finished Engineered Wood after 24 Firs
As part of the project, emissions have been characterized
from four types of finished engineered wood: 1)
particleboard finished with melamine; 2) particleboard
finished with vinyl; 3) finished veneered hardboard; and 4)
finished veneered particleboard. The test samples were
obtained directly from the manufacturing line at the
finishing plant. The finished samples were cut into small
coupons (3 by 3 in., 7.44 by 7.44 cm) and placed in 1-gal.
(3.785 L) steel containers with one coupon per container.
The containers were transported to Research Triangle
Institute within 24 hours of collection.
Figure 6 shows 24-hour emission rates of total VOCs from
each of the substrates. The finished veneered particleboard
and hardboard have substantially higher emission rates of
total VOCs compared to the vinyl and melamine
particleboard. As seen in Figure 7,31-day emission rates of
formaldehyde from the finished substrates were also higher
than 24 hr emissions rates of formaldehyde from the
melamine and vinyl particleboard (217 and 275 (ig/m2/hr
compared to 53 and 71 (jg/m2/hr).
Additional testing indicated that surface finishes applied to
the veneered particleboard and hardboard were a significant
source of emissions from the finished board (Figure 8).
These tests also showed that particleboard was also a
significant source of emissions from the finished veneered
particleboard.
Two studies are currently underway to evaluate low-
emitting surface finishes and engineered wood materials.
The goal is to identify low-emitting materials that may be
substituted for the existing finishes and engineered wood to
reduce emissions from the finished board. (EPA Contact:
Kelly W. Leovic, 919-541-7717, kleovic@engineer.
aeerl.epa.gov)
D Acetone D Formaldehyde Hexanal D Other
s
HI
1,400
1,200
1,000
800
600
400
200
0
31 days
275
PBVST
HBVSST
PBVY
PBVST = Veneered Particleboard with Sealer and Topcoat
HBVSST = Veneered Hardboard with Stain, Sealer, and Topcoat
PBVY = Particleboard with Vinyl
PBM = Particleboard with Melamine
Figure 7.
2,000
_ 1,800
I 1,600
1 1'400
t 1,200
I 1,000
j, 800
.8 600
ui 400
200
0
Figure 8.
Comparison of Aldehyde and Ketone
Emission Rates at 24 Hrs and 31 Days
D Alcohols Aldehydes/Ketones D Other VOC
S"
J"
.. -
-19 ^22
PB V PBV PBVS
PB = Particleboard
V = Veneer
PBV = Veneered Particleboard
PBVS = Veneered Particleboard with Sealer
PVBST = Veneered Particleboard with Sealer and Topcoat
Emission Rates of Total VOCs from Various
Components of Finished Veneered Particleboard
(31 Days)
Inside IAQ, Spring/Summer 1996
Page 5
-------
COST-EFFECTIVENESS OF ALTERNATIVE IAQ
CONTROL TECHNIQUES
IEMB is developing technical guidance that will assist users
in selecting and designing the most cost-effective
combination of IAQ control options in any specific
circumstance. The initial guidance will be general guidance
for commercial and institutional buildings, based on a
limited number of case studies. The first case study to be
conducted under this program has been partially completed.
A case study involves: 1) detailed definition of all key
building, HVAC, source, occupancy, and lAQ-related
parameters for the particular scenario to be studied; and 2)
a sensitivity analysis estimating the cost-effectiveness of
ventilation, air cleaning, and specific source management
steps as each of these parameters is varied.
The initial case study has addressed an existing 3-story
office building with an area of 10,000 ft2 (930 m2) per
story. To consider a range of possible interior
configurations, the first and third floors were assumed to
consist of enclosed offices around the perimeter, while the
second floor was open, containing modular workstations. A
suitable HVAC system was specified for the building, and
a variety of typical VOC emission sources were distributed
throughout the building. The incremental changes in total
annual costs (including annualized capital costs as well as
operating and maintenance costs) and the incremental
changes in annual VOC exposure to occupants at various
locations within the building, calculated as the IAQ control
approaches, were systematically varied. The parameters
varied in this sensitivity analysis included: the amount of
OA provided by the HVAC system; the efficiency of a
retrofit carbon-sorption VOC air cleaner; and the extent of
source management (which in this case consisted of the use
of low-emitting VOC sources).
The results for increased OA and for VOC air cleaners are
presented in Figure 9 for the case study building. The y-axis
shows cost-effectiveness, defined as the dollar cost per unit
reduction in individual exposure during the first year of
building occupancy - i.e., the total incremental cost for the
IAQ control step during the first year, divided by the
reduction in VOC exposure to the average occupant
(expressed as mg/m3-hr) during that year. Cost-
effectiveness is shown as a function of the percentage
reduction in exposure, relative to the baseline ("no-control")
case, to identify the more efficient control measures.
Source management is not shown in Figure 9, since the
costs of "low-emitting" materials are difficult to estimate.
This figure will be used to determine what premium could
be paid for low-emitting materials before that source
management step would no longer be cost-competitive with
increased ventilation and air cleaning.
The baseline case corresponds to an OA supply of 5
cfm/person (2.35 L/sec), and no VOC air cleaning. The
five circles on the curve for increased OA ventilation in
Figure 9 correspond to increases in the OA supply to 20,
40, 60, 80, and 100 cfm/person (9.4, 18.8, 28.2, 37.6, and
47 L/sec). The three points marked on each curve for the air
cleaning system show the effects if the fixed charge of
carbon in the system were assumed to provide an average
VOC removal efficiency of 12, 50, or 88% over each of the
indicated carbon lifetimes.
The cost of air cleaning will depend significantly on the
frequency with which the carbon sorbent needs to be
replaced. That frequency, in turn, will depend on the nature
and the concentration of the VOCs. Due to this uncertainty,
a parametric family of curves is included for air cleaning,
showing the effect of alternative carbon replacement
frequencies. As shown in the figure, replacement at more
frequent intervals results in a substantial increase in cost. It
is reasonable to assume that the higher percentage
reductions will require more frequent replacement, and that
the lower reductions will require less frequent replacement.
The curve for increased ventilation shows a significant
increase in cost as the percentage reduction in exposure is
increased above 80% (corresponding to 80-100 cfm or 37.6
- 47 L/sec OA/person). This results from an increase in
HVAC retrofit capital cost when one increases to 100
cfm/person (47 L/sec).
Figure 9 suggests that, for building-wide VOC reductions
below about 70% in the study building during its first year,
increased OA ventilation is likely the more reasonable
approach, costing about $3 to 4 per mg/m3-hr reduction in
individual exposure. For building-wide reductions of 70 to
80%, VOC air cleaning could be competitive or perhaps even
slightly less expensive - with costs of about $2.50 to 4 per
mg/m3-hr - if the air cleaner is able to reliably achieve the
stated VOC removals with carbon lifetimes longer than 3
months. For very high reductions in exposure - above 80% -
it might be expected that the costs with either ventilation or air
cleaning might increase to about $7 per mg/m3-hr. In the case
of ventilation, this increase results from the required
replacement of existing HVAC equipment; in the case of air
cleaning, it results from the expected increase in carbon
replacement frequency. (EPA Contact: Bruce Henschel, 919-
541-4112, bhenschel@ engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1996
Page 6
-------
2 a
^ ^
w o
o o
Q. O
X
11
10
9
i§!
in
0
D) O
E 0
KEY:
- Increased OA Ventilation
' VOC Air Cleaning
7R -\j
3'm°nthc
7 .^"HMfa
3 6-irjonfh e.. ~ ~ - -;4 -\
H -...
carbon lifetir
e
-X--X
50 55 60 65 70 75 80 85 90 95
% Reduction in VOC Exposure by Average Occupant During First Year
100
Figure 9. Cost-effectiveness of Increased OA Ventilation and of VOC Air Cleaning in the 3-story Office Building
(Assumptions: Equipment Lifetime - 10 years; Interest Rate - 7%; Cost of Electricity - $0.06/kWh)
QUALITY ASSURANCE FOR EPA'SIAQ RESEARCH
IEMB research covered in Inside IAQ responds to EPA quality
assurance (QA) requirements mandated by EPA Order 5360.1,
which establishes policy and program requirements for the
conduct of QA for all environmentally related measurements
performed by or for EPA. Its primary goal is to ensure that all
measurements supported by EPA produce data of known quality.
IEMB researchers use systematic planning to develop
acceptance or performance criteria for data collection whether it
is collected in the laboratory, in the field, or is produced by
models using information obtained from the literature.
Many of IEMB's research programs are carried out in on-site
facilities which include small chambers, a large chamber, and a
test house. All IEMB facilities have established fully functional
facility operating manuals as guidance documents to operations.
These facility manuals describe laboratory design specifications
and equipment, personnel capabilities and work capacity,
planning protocols, operating procedures, QA and quality control
requirements, and health and safety requirements. They also
contain test plan matrices including schedules and milestones.
They are living documents kept current, and once a year they are
formally reviewed and updated.
IEMB extramural research occurs off-site using the services of
contractors or cooperates. This work is performed via
contracts, cooperative agreements, or interagency agreements
(lAGs). Research using "in-kind" resources can occur via
cooperative research and development agreements (CRADAs) or
memoranda of understanding (MOU). When cooperating with
other federal agencies or organizations, EPA works with the
agency or organization to establish adequate QA requirements.
IEMB personnel produce various work products. Research
results are disseminated in published reports, at technical
meetings, or in the technical literature. EPA publications that
report measurement data contain sections discussing the quality
of the data in the report. The quality section discusses data
quality indicators such as accuracy (measurement system bias),
precision, completeness, representativeness, and comparability of
data. In quality research, standard sampling and analysis
methods are used where feasible, although because of the cutting
edge nature of some research, some methods may be developed
as the work progresses. Instruments are calibrated, and quality
control checks are performed periodically to keep the
measurements on track. Audits may be performed by QA
personnel as an independent check on performance. All of these
topics may be among the indicators of quality discussed in the
QA section of published reports.
Another product of IEMB research is computer models which
can predict the possible outcomes of various environmental
measurements using as input the often vast databases on the
subject in the technical literature. Care is taken that the
mathematical manipulations of the data produced by the
software are those intended. (EPA Contact: Shirley Wasson,
919-541-1439, swasson@ engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1996
Page 7
-------
EMISSIONS OF CARBONYL COMPOUNDS FROM
LATEXPAINT
Emissions of carbonyl compounds from an interior latex paint
were investigated in lEMB's test house. A white flat latex
paint purchased from a local store was applied to the walls of
a bedroom in the test house. The windows were open for the
first 4 hours, and a box fan was placed in one of the windows.
To determine the concentrations of carbonyl compounds, air
samples were collected on dinitrophenylhydrazine (DNPH)
cartridges and analyzed by high performance liquid
chromatography (HPLC). The OA samples were taken in the
backyard; indoor samples were taken from the painted
bedroom and the den area of the house.
Three carbonyl compounds were consistently found in the OA
samples and seven in the indoor samples (see Table 2). Trace
amounts of methacrolein [methacrylaldehyde
CH=C(CH3)CHO] were found in the OA samples.
Crotonaldehyde (2-butenal, CH3=CHCHCHO) was found in
the indoor air samples after paint application, but only in the
painted room on day 1. Low levels of butanone (methyl ethyl
ketone, CH3COCH2CH3) and butanal (CH3CH2CH2CHO)
were found in indoor samples before and after painting.
During this test, indoor concentrations of carbonyl compounds
were higher than outdoor concentrations. After paint
application, indoor formaldehyde concentrations in the painted
bedroom increased slightly (less that 30%). Among the seven
carbonyl compounds listed in Table 2, only the acetaldehyde
concentration changes were significant (see Figure 10). The
levels of carbonyl compound concentrations in the den are
consistently lower than those in the bedroom. However, all the
indoor carbonyl compound concentrations decreased to the
background indoor levels within 24 hours. (EPA Contact: John
Chang, 919-541-3747, jchang@ engineer.aeerl.epa.gov)
Table 2. Carbonyl Compounds Measured Indoors and
Outdoors During Latex Paint Application *
Inside Inside
Compound Outdoors (Before Test) (During Test)
Formaldehyde
Acetaldehyde
Acetone
Propanal
Benzaldehyde
Pentanal
Hexanal
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
* Minimum Quantification Limit =
E
i1
d
g
o
30
2b
20
15
10
5
; !
-
: \
^
I , I
\
w^-^^
0-^~-D D ^^t""
I , I
Bedroom
Den
Outdoors
4
e
-200 -100 0 100 200 300 400
Figure 10. Acetaldehyde (gteffi^tfeJfon Profile (paint
was applied at 0 hours)
APPCD-Air Pollution Prevention &
Control Division
CFM-Cubic Feet per Minute
CFU-Colony Forming Units
CRADA-Cooperative Research and
Development Agreement
DNPH-dinitrophenylhydrazine
FS-Floating Slab
HPLC-High Performance Liquid
Chromatography
GLOSSARY OF ACRONYMS
HVAC-Heating, Ventilating, and Air-
Conditioning
lAG-Interagency Agreement
lAQ-Indoor Air Quality
lEMB-Indoor Emissions Management
Branch
IMA-Inhibitory Mold Agar
MOU-Memoranda of Understanding
NRMRL-National Risk Management
Research Laboratory
NTIS-National Technical
Information Service
OA-Outdoor Air
QA-Quality Assurance
RAETRAD-Radon Emanation and
Transport into Dwellings
RH-Relative Humidity
SSW-Slab-In-Stem Wall
VOC-Volatile Organic Compound
Inside IAQ, Spring/Summer 1996
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SUMMARIES OF RECENT PUBLICATIONS
This section provides summaries of recent
publications on EPA's indoor air research.
The source of the publication is listed after
each summary. Publications with NTIS
numbers are available (prepaid) from the
National Technical Information Service
(NTIS) at : 5285 Port Royal Road,
Springfield, VA 22161, 703-487-4650 or
800-553-6847.
Demonstration of Radon Resistant
Construction Techniques, Phase II-Subslab
mitigation systems were installed (in
accordance with draft standards) in 15 new
Florida houses in 1992. Soil radon levels
ranged from just under 500 to over 8000
pCi/L. Evaluation of the systems showed
that: 1) all systems extend negative pressure
to practically all areas under the slab; 2)
slabs tended to crack less than expected; and
3) intact vapor barriers under new houses
prevent radon intrusion through slab cracks
in most instances, but slab pipe penetrations
not sealed in accordance with standards can
contribute to relatively high indoor radon
levels. Eleven mitigation systems were
installed using ventilation matting, and four
systems used a wellpoint suction pipe. Both
systems performed well if carefully installed.
The highest indoor radon level with the
mitigation system capped off was 5.6 pCi/L
over 48 hours. Ten houses were under 2.9
pCi/L and did not require activation of their
mitigation systems. Five houses required
activation of their mitigation systems. All
houses are currently under 2.9 pCi/L.
Source: EPA Report, EPA-600-R-95-159,
NTIS PB96-121512, November 1995. (Lead
Author: James L. Tyson; EPA Contact:
David C. Sanchez, 919-541-2979,
dsanchez@ engineer.aeerl. epa.gov)
Entrainment by Low Air-Liquid Ratio
Effervescent Atomizer Produced Sprays-
This paper describes entrainment into sprays
produced by an aerosol consumer product
dispenser that allows substitution of waterfor
VOC solvents and air for hydrocarbon
propellants. Experimental data are analyzed,
along with measured momentum rate data.
The analysis shows that dimensionless
entrainment by sprays produced using this
type of atomizer is accurately predicted,
using: 1) distance along the spray axis; 2)
exit orifice diameter; 3) spray momentum
rate at the exit orifice; 4) density of the
entrained air; 5) entrained gas mass flow
rate; 6) mass flow rate of liquid exiting the
dispenser; and 7) an entrainment number
whose value is 0.15 ± 0.056. Source:
Proceedings of Institute for Liquid
Atomization and Spray Systems, May 1996.
(Lead Author: Jeff J. Sutherland; EPA
Contact: Kelly W. Leovic, 919-541-7717,
kleovic@engineer .aeerl.epa.gov)
Evaluation of Radon Emanation from Soil
with Varying Moisture Content in a Soil
Chamber-Measurements of the emanation
coefficient and diffusion of radon in soil
contained in a 2 by 2 by 4 m chamber using
a range of moisture contents are described.
In addition, equal amounts of well-mixed
over-dried soil were placed in 20 L
aluminized gas-sampling bags, and after
approximately 1 month of in-growth, radon
samples were taken, after which water was
added, and another period of in-growth and
sampling followed. The emanation
coefficients and radon concentrations in the
gas bag experiment were observed to
increase with increasing moisture content
and then decrease before reaching saturated
conditions. The emanation and diffusion
effects on the radon concentration soil
gradient were identified for this sandy soil
having approximately 200 Bq kg "' radium
and a soil density of 1682 kg m"3. Source:
Accepted for publication in Environment
International, Alexandria, VA, January
1996. (Lead Author and EPA Contact: Marc
Y. Menetrez, 919-541-7981, mmenetrez@
engineer.aeerl. epa.gov)
Growth Evaluation of Fungi (Penicillium
and Aspergillus ssp.) on Ceiling Ji'fes-The
potential for fungal (Penicillium and
Aspergillus ssp.) growth on four different
types of ceiling tiles was evaluated in static
chambers. It was found that even new
ceiling tiles could support fungal growth
when at equilibrium with a RH as low as
85% and corresponding moisture content
greater than 2.2%. Used ceiling tiles
appeared to be more susceptible to fungal
growth than new ones. In the 70% RH
chamber with wetted tiles under slow-drying,
non-equilibrium conditions, fungi could still
proliferate as long as the moisture level in
the ceiling tiles was adequate. Fungal growth
could be limited if the wetted ceiling tiles
were dried quickly and thoroughly. Source:
Atmospheric Environment, 29, 17, 2331-
2337,1995. (Lead Author and EPA Contact:
John Chang, 919-541-3747, jchang@
engineer.aeerl.epa.gov)
HVAC Systems as a Tool in Controlling
Indoor Air Quality: A Literature Review-
This report reviews the literature on the use
of HVAC systems to control LAQ. One
conclusion of the review is that HVAC
systems often contribute to indoor air
pollution because of 1) poor system
maintenance, 2) overcrowding or the
introduction of new pollution-generating
sources within buildings, and 3) the location
of OA intakes near ambient pollution
sources. Additionally, failure to trade off
between energy conservation and employee
productivity may result in increased IAQ
problems. Source: EPA Report, EPA-600/R-
95-174, NTIS PB96-140561, December
1995. (Lead Author: MaxM. Samfield; EPA
Contact: David C. Sanchez, 919-541-2979,
dsanchez@ engineer.aeerl .epa.gov)
Measurement of Indoor Air Emissions from
Dry-Process Photocopy Machines- A
standard test method to measure emissions
from office equipment is being developed in
order to investigate pollution prevention
approaches for reducing emissions (e.g.,
ozone, VOCs, and particles). Initial results
from four dry-process photocopy machines
indicate that the method provides acceptable
performance for characterizing emissions,
can adequately identify differences in
emissions between machines, and is capable
Inside IAQ, Spring/Summer 1996
Page 9
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of measuring both into- and inter-machine
variability in emissions. The compounds
with the highest emission rates overall were
ethylbenzene (28,000 ^g/hour), wz,/?-xylenes
(29,000 Mg/hour), o-xylene (17,000 Mg/hour),
2-ethyl-l-hexanol (14,000 Mg/hour), and
styrene (12,000 ^g/hour). Although many of
the same compounds tended to be emitted
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.
Ozone emissions ranged from 1,300 to
7,900 Aig/hour. Source: Journal of the Air &
Waste Management Association, September
1996 (Lead Author & EPA Contact: Kelly
W. Leovic, 919-541-7717,
kleovic@engineer.aeerl. epa.gov)
Re-Entrainment and Dispersion of
Exhausts from Indoor Radon Reduction
Systems: Analysis of Tracer Gas Data-
Tracer gas studies were conducted around
four model houses in a wind tunnel and one
house in the field to quantify re-entrainment
and dispersion of exhaust gases released
from residential radon reduction systems.
Field re-entrainment tests suggest that active
soil depressurization systems exhausting at
grade level can contribute indoor radon
concentrations 3 to 9 times greater than
systems exhausting at the eave. With a high
exhaust concentration of 37,000 Bq/m3, the
indoor contribution from eave exhaust re-
entrainment may be only 20 to 70% of the
national average ambient level in the U.S.
(about 14 Bq/m3), while grade-level exhaust
may contribute 1.8 times the average. The
grade-level contribution would drop to only
0.18 times ambient if the exhaust were 3,700
Bq/m3. Wind tunnel tests of exhaust
dispersion outdoors suggest that grade-level
exhaust can contribute mean concentrations
beside houses averaging 7 times greater than
exhaust at the eave, and 25 to 50 times
greater than exhaust midway up the roof
slope. With 37,000 Bq/m3 in the exhaust, the
highest mean concentrations beside the
house could be less than or equal to the
ambient background level with eave and
mid-roof exhausts, and 2 to 7 times greater
with grade exhausts. Source: Indoor Air,
5(4):270-284 (1995). (Lead Author and EPA
Contact: D.B. Henschel, 919-541-4112,
bhenschel@engineer.aeerl. epa.gov)
Residential Radon Resistant Construction
Feature Selection System-T\ns report
describes a proposed residential radon
resistant construction feature selection
system that consists of engineered barriers to
reduce radon entry. Proposed standards in
Florida require radon resistant features in
proportion to regional soil radon potentials.
The effectiveness of different radon control
features was estimated from new laboratory
measurements, analyses of new and previous
house studies, and mathematical model
simulations. The laboratory measurements
characterized five polyethylene subslab
membranes. The analyses showed that both
monolithic-slab (mono) and Slab-in-Stem
Wall (SSW) foundation designs can
passively control indoor/subslab radon ratios
to average levels that are slightly lower than
measurements in other houses the previous
year, and two to four times lower than ratios
from earlier studies. The mono design offers
about twice as much passive radon
resistance as SSW designs. A Florida radon
protection map was developed to show
where the active and passive features are
needed. Source: EPA Report, EPA-600/R-
96-005, NTISPB96-153473, February 1996.
(Lead Author: Kirk K. Nielson; EPA
Contact: David C. Sanchez, 919-541-2979,
dsanchez@ engineer.aeerl.epa.gov)
Site-Specific Characterization of Soil
Radon Potentials-Empirical measurements
suggest that the precision of soil radon
measurements is marginal, leaving an
uncertainty of about a factor of 2 in site-
specific estimates. Although this may be
useful for some applications, it probably is
inadequate for most decisions about
construction of radon-resistant features.
More detailed site characterization (soil
borings and measurements of radium,
emanation, moisture, and permeability
profiles) can improve precision; however, the
additional expense may not be justified in
comparison to the cost of installing the
features. Field tests of soil radon flux and
moisture measurements were conducted at
26 house sites in Polk County, Florida, to
evaluate their utility in predicting site-
specific radon potentials. Results showed
localized trends in radon potential that
compared well with mapped radon
potentials in some cases, but not in others.
For the 26 houses, the site-specific radon
potentials averaged twice the potentials from
the generalized radon maps. Source: EPA
Report, EPA-600/R-95-161, NTIS PB96-
140553, November 1995. (Lead Author:
Kirk K. Nielson; EPA Contact: David C.
Sanchez, 919-541-2979, dsanchez@
engineer.aeerl.epa.gov)
Status of EPA 'sBioresponse-Based Testing
Program-Since 1990 EPA has been
investigating the feasibility of using
biological methods based on human, animal,
or in vitro responses to characterize sources
of indoor air emissions. The "bioresponse"
methods being evaluated measure odor and
sensory irritation of mucosal tissues in the
eyes, nose, and upper airways. Chambers for
creating controlled emissions from sources
are basically the same as those used for
traditional studies of emission rates and
chemical compositions. Studies of human
subject responses to known odorous or
sensory irritant chemicals using nose-only,
eye-only, facial, and whole-body exposures
are providing baseline data against which
animal and in vitro results will be validated.
The animal and in vitro methods being
investigated measure changes in respiratory
patterns and chemosensory evoked
potentials. The status of current and future
projects is reported. Source: American
Society of Testing & Materials publication
STP1287, 1996. (Lead Author and EPA
Contact: W. Gene Tucker, 919-541-2746,
gtucker@engineer.aeerl. epa.gov)
Test Cell Studies of Radon Entry-Tbis
report compares slab-in-stem wall (SSW)
with floating slab (FS) construction
practices, measures radon transport and
entry for model testing, develops protocols
relevant to depressurized radon measure-
ments, and determines the effect of high
radium fill soil on indoor radon. The indoor
radon concentrations in the FS cell were 3.5
times higher than those in the SSW cell.
These results agreed with predictions by a
radon entry and transport (RAETRAD)
model. Whole building stresses and slab area
and crack length radon entry were
measured, and they yielded comparable
results. Experiments in the fill study suggest
that the amount of emanating soil radium is
a good predictor for radon entry into a
structure. Source: EPA Report, EPA-600/R-
96-010,NTISPB96-153549,February 1996.
(Lead Author: Ashley D. Williamson; EPA
Contact: David C. Sanchez, 919-541-2979,
dsanchez@ engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1996
Page 10
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Name
Michael C. Osborne
John C. S. Chang
D. Bruce Henschel
Betsy M. Howard
Mark A. Mason
Marc Y. Menetrez
Ronald B. Mosley
Richard B. Perry
Leslie E. Sparks
W. Gene Tucker
James B. White
CONTACTS IN IEMB
Research Areas
Branch Chief
Biocontaminants, VOC Source/Sink Characterization, VOC
Emissions Modeling
Cost Analysis of IAQ Control Techniques, Building Energy
Modeling, Radon Reduction in Existing Houses
Pollution Prevention, Particle Board, Large Chamber Testing,
Conversion Varnishes
Bioresponse Methods Development, Chemical Source Characteriz-
ation, Large Chamber Testing
Large Building Measurements (IAQ, Ventilation, Building
Dynamics HVAC, Diagnostic Strategy)
Indoor Air Pollutants Originating in Soil, Mathematical Modeling,
Indoor Particles, Soil Contaminants
Radon Diffusion Measurement, Test Method Development,
Ventilation Systems Research
IAQ and Exposure Modeling, Air Cleaners, Indoor Particles
Control of IAQ, ASHRAE Standard 62, Bioresponse Methods,
Source Emissions, Indoor/Outdoor Particles
Development of Low-Emitting/Low-Impact Sources, IAQ Emission
Source Catalog & Database, IAQ & Life Cycle Assessment, Envir-
onmental Resources Guide, Expert Systems for Facilities Design &
Operation Development of CADD-based LCA for IAQ, Textiles
Phone E-mail
919-541-4113 mosborne@*
919-541-3747 jchang@*
919-541-4112 bhenschel@*
919-541-7915 bhoward@*
919-541-4835 mmason@*
919-541-7981 mmenetrez@*
919-541-7865 rmosley@*
919-541-2721 rperry@*
919-541-2458 lsparks@*
919-541-2746 gtucker@*
919-541-1189 jwhite@*
: (all E-mail @) engineer.aeerl.epa.gov
Inside IAQ, Spring/Summer 1996
Page 11
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Call for Papers
Engineering Solutions to Indoor Air Quality Problems
The second biennial Engineering Solutions to Indoor Air Quality Problems Symposium, an international symposium cosponsored by
the Air & Waste Management Association and EPA's National Risk Management Research Laboratory, will be held July 21-23,1997,
at the Sheraton Imperial Hotel and Conference Center in Research Triangle Park, NC. Papers are invited on the following topics:
! Managing the Risk of Indoor Air Pollution ! Ventilation
! Indoor Air Source Characterization Methods ! HVAC Systems as Sources of
! Indoor Air Source Management Indoor Air Pollution
! Low Emitting/Low Impact Materials Development ! Air Duct Cleaning
(Pollution Prevention) ! Particles in Indoor Air
! Biocontaminant Prevention and Control ! Indoor Air Quality Modeling
! Indoor Air Cleaning Methods ! Costs of Managing Indoor Air Quality
The two and a half-day symposium will consist of one general session so that participants will be able to attend all sessions. A poster
session, continuing education courses, and an exhibition of related products and services are also planned.
Send abstracts of 200-300 words by January 10, 1997 to: Kelly W. Leovic, U.S. EPA, MD-54, Research Triangle Park, NC 27711;
Telephone (919) 541-7717; Fax (919) 541-2157; E-mail: kleovic@engineer.aeerl.epa.gov. Abstracts should include paper title and
author(s) names, address(es), and phone, fax number(s), and e-mail address (if applicable).
United States
Environmental Protection Agency
Indoor Environment Management Branch
MD-54
Research Triangle Park, NC 27711
Official Business
Penalty for Private Use
$300
EPA/600/N-96-002, Spring/Summer 1996
An Equal Opportunity Employer
FIRST CLASS MAIL
POSTAGE AND FEES PAID
EPA
PERMIT No. G-35
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