United States Environmental
Protection Agency
Office of Research and Development
Research Triangle Park, NC 27711
EPA/600/N-97/003 Spring/Summer 1997
&EFA
Inside I A Q
EPA's Indoor Air Quality Research Update
VOC EMISSIONS FROM LATEX PAINT: SINK
EFFECTS
Interior latex paint - used for ceilings, walls, and wood
products - is a source of volatile organic compounds
(VOCs) in the indoor environment. Emissions are primarily
from the release of organic solvents commonly used as
coalescents and from freeze/thaw stabilizers in the paint.
Over the past 2 years, EPA has been evaluating VOC
emissions from latex paint. Efforts have been concentrated
on a flat white latex paint with a vinyl acetate monomer.
VOC emissions from this paint consist of four major
compounds: propylene glycol, ethylene glycol,
butoxyethoxyethanol (BEE), and Texanol. Initial testing
identified significant substrate effects on VOC emission
profiles and, as a result, "real" substrates such as gypsum
board and wood were suggested for future testing. Models
were also developed and validated for prediction of both
short- and long-term emission rates.
To further assess the impact of VOC emissions from latex
paint on indoor air quality (IAQ) and human exposure, sink
effects (i.e., the adsorption and desorption interactions
between the emitted VOCs and the interior surfaces) were
evaluated in environmental chambers. This article covers
the results of the sink effect evaluations of two common
indoor materials, carpet and gypsum board, on the four
major VOCs emitted from the latex paint tested.
Method
Each chamber test included two phases. Phase 1 was the
dosing/adsorption period during which sink materials
(carpet and gypsum board samples) were exposed to the
four VOCs. The sink strength of each material tested was
characterized by the amount of the VOCs adsorbed. Phase
2 was the purging/desorption period during which the
chambers containing the dosed sink materials were flushed
with purified air. The reemission rates of the adsorbed
VOCs from the sinks were reflected by the amount of the
VOCs being flushed.
(Continued on Page 2)
In This Issue
VOC Emissions from Latex Paint: Sink Effects 1
The Effectivness of Antimicrobial
Surface Treatments 5
Field Study on Residential Air Duct Cleaning 6
Emissions from Acid-Catalyzed Varnishes 8
Measuring Toner Emissions Using Headspace Analysis 9
A Large Chamber Test Method for Measuring
Emissions from Office Equipment 10
Glossary of Acronyms 11
IEMB Papers from Symposium 12
Summaries of Other Recent Publications 15
Inside IAQ is distributed twice a year and highlights IAQ
research conducted by EPA's National Risk Management
Laboratory's (NRMRL) Indoor Environment Management
Branch (IEMB). 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
Art. Kelly Leovic (MD-54)
U.S. EPA
Research Triangle Park, NC 27711
Fax: 919-541-2157
E-Mail: kleovic@engineer.aeerl.epa.gov
Inside IAQ, Spring/Summer 1997
Page 1
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Results
Tables 1 and 2 summarize results for the adsorption and the
desorption phases, respectively. Chamber concentration
profiles are in Figures 1 through 4 for the adsorption and
desorption of ethylene glycol and Texanol on gypsum board.
If there were no sink effects and the chamber air was well
mixed, mass balance indicates that the chamber VOC
concentration in the adsorption phase, Cs, should approach
the value of Cm (the average inlet concentration) as:
Cs = Cm (1 - e-Nt)
where t = time, h, and N=air exchange rate, h"1 .
(1)
The chamber VOC concentration during the desorption
phase, Cd, should decrease exponentially:
Cd = Cdoe-Nt (2)
where Cdo = chamber VOC concentration at the inception of
desorption phase, mg/m3.
Figures 1 and 3 show that, during the adsorption phase, the
chamber outlet concentrations, Cs, were considerably lower
than those predicted by Equation (1) which assumes no sink.
The differences between the predicted concentration and the
actual chamber concentration were attributed to sink effects.
Table 1 shows that, even at the end of the 168 hour
adsorption period, chamber concentrations, Cout, were still
considerably lower than Cm.
The sink effects during the desorption phase are reflected by
the differences between the concentrations predicted by
Equation (2) and the chamber data shown in Figures 2 and 4.
Equation (2) predicts that, without sink effects, the chamber
concentration should decrease to below 0.1 mg/m3 within 10 h.
Nevertheless, experimental data in Figures 2 and 4 show that
the actual chamber concentrations were well above 0.1 mg/m3.
Table 2 indicates that, when carpet was the sink material, the
chamber concentrations, Cend, were greater than 0.1 mg/m3
even after 300 hours of purging.
(Continued on Page 3)
Table 1. Mass Balance for the Dosing Period (Adsorption)
Test
Compound
Propylene Glycol
Ethylene Glycol
BEE
Texanol
Propylene Glycol
Ethylene Glycol
BEE
Texanol
Test
Material
Gypsum
Gypsum
Gypsum
Gypsum
Carpet
Carpet
Carpet
Carpet
cm
(mg/m3)
5.32
7.12
3.43
5.43
5.38
5.68
3.80
6.21
Dosing
Period (h)
168
168
168
168
168
168
169
169
^out
(mg/m3)
1.53
3.69
1.83
2.68
2.11
2.56
1.72
4.60
Dosage
(mg/m2)
893
1196
576
921
903
954
642
1049
Mads
(mg/m2)
488
628
317
483
627
662
264
232
Mads/Cm
(m)
91.7
88.2
92.4
89.0
116.5
116.5
69.5
37.4
Cm = average inlet concentration
Cout = outlet concentration at the end of dosing period
Mads = mass adsorbed by the sink by the end of dosing period
Table 2. Mass Balance for the Purging Period (Desorption)
Test
Compound
Propylene Glycol
Ethylene Glycol
BEE
Texanol
Propylene Glycol
Ethylene Glycol
BEE
Texanol
Test
Material
Gypsum
Gypsum
Gypsum
Gypsum
Carpet
Carpet
Carpet
Carpet
Cend
(mg/m3)
0.09
0.11
0.03
0.08
0.45
0.52
0.13
0.16
Purging
Period (h)
356
356
387
387
291
291
340
340
Mads
(mg/m3)
488
628
317
483
627
662
264
232
Mdes
(mg/m2)
55.7
76.8
43.4
85.5
204
246
78
163
Mdes/Mads
(%)
11
12
14
18
33
37
30
70
Cend = outlet concentration at the end of purging period
Mdes = mass desorbed from sink during purging period
Inside IAQ, Spring/Summer 1997
Page 2
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10
o
O
40 80 120
Elapsed Time (h)
160
Average Inlet Cone. (Cin) No-Sink Model
Outlet Cone. (Cs) — Surface Adsorption Model
Figure 1. Adsorption of Ethylene Glycol from
Gypsum Board in Dosing Phase
-S 6
OB
o
§ 2
O
40 80 120
Elapsed Time (h)
160
Average Inlet Cone. (Cin) No-Sink Model
D Outlet Cone. (Cs) - Surface Adsorption Model
Figure 3. Adsorption of Texanol from
Gypsum Board in Dosing Phase
10
o
O
0.1
100 200 300
Elapsed Time (h)
400
° Outlet Cone. (Cd)
• Surface Adsorption Model
— No-Sink Model
Figure 2. Desorption of Ethylene Glycol from
Gypsum Board in Purging Phase
10
•3 1
I
o
0.1
100 200 300
Elapsed Time (h)
400
° Outlet Cone. (Cd)
• Surface Adsorption Model
— No-Sink Model
Figure 4. Desorption of Texanol from
Gypsum Board in Purging Phase
Sink Strength
The sink strength of the gypsum board and carpet test
samples can be characterized by a factor Ke defined as:
Ke = Me/Ce (3)
where Me = sink surface organic concentration in
equilibrium with Ce, mg/m2, and Ce = gas-phase organic
concentration in equilibrium with Me, mg/m3.
Ke is the equilibrium capacity of the sink surface for the
specific VOC. That is, Ke indicates the maximum quantity
(mg/m2) of the VOC adsorbed by the test sample in
equilibrium with the gas-phase VOC concentration (mg/m3).
If equilibrium were reached at the end of the adsorption
phase, the chamber concentration should be equal to the
inlet concentration and can be considered as Ce. Me should
be equal to the amount of VOC adsorbed per unit area, Mads,
at the end of each adsorption phase:
(Continued on Page 4)
Inside IAQ, Spring/Summer 1997
Page 3
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Mads = NV(Am-Aout)/S (4)
where, Am = area under Cm curve in chamber concentration
profile for adsorption phase, (mg/m3)h; Aout = area under
Cout curve in chamber concentration profile for adsorption
phase, (mg/m3)h; and S = sink surface area, m2.
However, Table 1 shows that equilibrium was not reached at
the end of the adsorption phase in any of the chamber tests.
The estimated values for Mads, based on chamber data and
Equation (4), are listed in Table 1. By definition, Me should
be greater than the Mads estimated for current cases.
Correspondingly, the value of Ke should always be greater
than that of Mads/Cm listed in the last column of Table 1.
The sink strengths meaured in this study are much higher than
those measured in previous studies. For example, earlier IEMB
research measured the sink strength of a carpet and a
wallboard for tetrachloroethylene and ethylene. The values of
K, were in the range of 0.142 to 0.97 m. Another IEMB study
estimated the sink strength in a test house (a combination of
carpet and gypsum board) for four alkane species: octane,
nonane, decane, and undecane. The values of K,, were in the
range of 0.90 to 6.25 m. It is apparent that the values of
Mads/Cm listed in Table 1 and the corresponding K,, values are
considerably greater than those K^ values measured in these
previous studies. One explanation is that the sink strength is a
function of the physical and chemical properties of the VOCs
being adsorbed and desorbed. It also possible that the sink
strength of materials such as carpet and gypsum board toward
oxygenated polar compounds is considerably higher than that
toward non-polar VOCs.
Reemissions
Table 2 shows that, after approximately 300 h of purging
with clean air, the majority of the VOCs adsorbed still
remained in the sinks. Overall, after over 300 h, less than 18
and 70% of the VOCs were reemitted from the gypsum
board and the carpet, respectively. Assuming that all the
VOCs in the sinks are reemittable and that the reemissions
proceed at a level similar to the purging rates measured at
the end of the desorption period, it will take several years for
all the VOCs adsorbed to reemit. The extremely slow
reemission process reflects the extraordinarily high sink
strength estimated from the adsorption data.
Surface Adsorption/Desorption Model
To account for the sink effects, a model based on a first
order reversible surface adsorption/desorption phenomenon
was applied. According to the model, the chamber
concentration during the adsorption phase can be predicted
by Equation (5) with initial conditions, Cs = 0 at t = 0,
Cs = Cm {1 - [(N - ri)exp(-r2t) - (N - r2)exp(-rit)]/ (r2 - r^} (5)
and the desorption phase chamber concentration predicted by
Equation (6) with initial conditions, Cd = Cdo at t = 0,
Cd = {[LkdMdo - (N+Lka- r2) Cdo]exp(-rit)-[LkdMdo-
(N+Lka-ri)Cdo]exp(-r2t)}/(r2 -rO (6)
where, It, = adsorption rate constant, m/h, kd = desorption rate
constant, h"1; Mdo = sink surface organic concentration at the
beginning of the desorption phase, mg/m2, N = air exchange
rate, h"1, L = chamber loading (S/V), m ~\ V = volume at
chamber, m3, and ^ and r2 = two parameters estimated by
ri 2 = {(N + Aka/V + kd) ± [(N + Ak./V + kd)2
-4Nkd]a5}/2 (7)
Equations (5), (6), and (7) were used to analyze the chamber
data, and the values of sink parameters, ka and kd, were
estimated by a non-linear regression curve fit routine,
implemented on a microcomputer. As illustrated by Figures 1
through 4, the model fit the adsorption phase data reasonably
well (Figures 1 and 3) but failed to predict the slow reemission
process (Figures 2 and 4). In general, the reemission model
tended to overpredict, and a better fit was obtained if one
assumed that only part of the adsorbed VOCs were reemittable.
The poor fit of the surface adsorption/ desorption model to the
long and slow reemission data seems to imply that other
mechanisms (such as diffusion or chemical reaction) were
controlling the desorption process.
Summary
In summary, the carpet and gypsum board tested have
significant sink effects on the four VOCs evaluated: propylene
glycol, ethylene glycol, BEE, and Texanol. Analysis of
environmental chamber data indicated that the sink strength of
the carpet and the gypsum board toward the four VOCs is
orders-of-magnitude higher than that toward other VOCs
studied previously (i.e., tetrachloroethylene, ethylene, and
alkane species). It is suspected that the physical/chemical
properties of those oxygenated polar compounds may have
significant effects on the sink behavior. If all the VOCs in the
sinks are reemittable, it will take years to complete the
desorption process for the four VOCs tested in this study. A
sink model based on surface adsorption and desorption
assumptions failed to simulate the chamber data during the
long-term reemission process but predicted the adsorption
phase fairly well. It is likely that the adsorption/desorption of
those four VOCs were not controlled by surface phenomena
but involved mechanisms such as chemisorption and/or
diffusion related processes. To determine whether 100% of the
adsorbed VOCs were reemittable, long-term desorption data
would be needed. (EPA Contact: John Chang, 919-541-3747,
e-mail, jchang@engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1997
Page 4
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THE EFFECTIVENESS
SURFACE TREATMENTS
OF ANTIMICROBIAL
The efficacies of three commercially available fungicidal
surface treatments for heating, ventilating, and air-conditioning
(HVAC) systems are being evaluated in a joint project between
IEMB and the National Air Duct Cleaning Association
(NADCA). The treatments are designed to prevent the
regrowth of microorganisms in HVAC systems.
Poor source control and/or ineffective filtration can cause the
interior surfaces of HVAC systems to become soiled with dirt,
dust, and debris overtime. Non-porous surfaces such
as galvanized sheetmetal can be treated using current air duct
cleaning (ADC) methods. Such techniques and equipment are
well established and are generally very effective. (See related
article on page 6, "Field Study on Residential Air Duct
Cleaning.")
However, if the HVAC surface is porous and is contaminated
with microbiological growth, as can occur on fiberglass duct
lining (FGDL), effective remediation procedures are not well
established. In fact, the EPA recommends that microbially
contaminated FGDL be removed rather than treated in-place.
Because FGDL replacement can be very expensive, some
ADC companies treat the contaminated FGDL in-place by: 1)
vacuuming the contaminated FGDL to remove as much
surface deposition and contamination as possible, 2) misting or
fogging the HVAC system with a biocide to kill the microbial
growth, and 3) encapsulating the remaining contamination in-
place with a fungicidal protective coating.
The primary objective of this research will be to determine the
efficacy of three commercially available fungicidal
encapsulants in preventing microbial regrowth over a period of
1 to 2 years when coated on existing contaminated FGDL.
Two simultaneous phases will be conducted: 1) in-situ field
experiments conducted at EPA's IAQ test house in Gary,
NC, and 2) laboratory experiments using static and dynamic
test chambers. The 121 m2 IAQ test house is 20 years old
including the air handler and duct work. The duct material is
galvanized sheetmetal and flexible ducts with FGDL. The main
supply air ductwork is located in the crawl space, and the air
handler is located in a closet in the living area.
The in-situ field experiments will involve applying the three
encapsulants on selected patches of FGDL in the test house
supply air ductwork. Surface samples from this ductwork
show that it is contaminated primarily with the fungus
cladosporium. Bioaerosol sampling in the air shows a
predominance of the fungus Penicillium spp.
Once applied, long-term monitoring microbiological
evaluations will be performed every 3 months for a period of
1 to 2 years. Field evaluations will include:
• sampling surface microbials on each coated patch,
• moisture meter readings,
• sampling the HVAC evaporator condensate during the
cooling season,
• measuring temperature and relative humidity (RH)
indoors and outdoors,
• measuring duct temperature and RH, and
• monitoring heating and cooling system duty cycle.
FGDL samples will be taken from the IAQ test house and
coated with the encapsulants for use in the laboratory growth
studies. Dynamic chambers will be used to determine growth
factors under "worst case" conditions of very high RH. Static
chambers will be used to evaluate the performance of the
encapsulants using an American Society of Testing and
Materials (ASTM) method developed under EPA sponsorship.
All air duct cleaning services, equipment, and personnel are
being provided by NADCA under the authority of the Federal
Technology Transfer Act. (EPA Contact: Russell N. Kulp,
919-541-7980; rkulp@engineer.aeerl.epa.gov)
Inside IAQ, Spring/Summer 1997
Page 5
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FIELD STUDY ON RESIDENTIAL AIR DUCT
CLEANING
A nine-home field study was conducted to investigate the
impact of mechanical ADC methods on IAQ and system
performance. ADC services were provided by NADCA. The
objectives were to: evaluate mechanical ADC methods
commonly used on non-porous surfaces; measure pre- and
post-ADC environmental system parameters to investigate any
impacts on IAQ; and measure system performance pre- and
post-ADC. Surface treatments, such as biocides and
encapsulants were not a part of the field study. All nine
residences are located in the Research Triangle area of NC.
Methods
Eight of the residences in the field study were occupied and the
ninth was the EPA's IAQ test house (TH). Each house was
equipped with a central heating and air-conditioning (HAC)
forced air distribtion system. ADC had not been performed on
the air handling unit (AHU) or duct system for at least 10
years. All occupants were nonsmokers and none of the houses
had IAQ complaints. Table 3 shows the characteristics of each
house.
Sampling procedures and instrumentation were identical for
each of the test houses, and measurements were made during
a 1-week study of each house. Pre- and post-ADC
measurements included: supply and return air duct dust surface
mass; airborne particle mass (PM) and fiber measurements;
microbial bioaerosol and surface sampling; temperature; RH;
carbon dioxide; and system performance factors such as static
pressure, air flow rates, motor current, and refrigerant
temperature.
The mechanical ADC methods and equipment used by
NADCA varied according to the house air distribution system,
configuration, and accessibility. ADC methods included
portable negative air systems to collect and remove loosened
dust and debris. Silica-carbide rotating brushes, air washing
with compressed air and air whips, contact vacuuming, and
hand wiping were used to loosen the dust and debris.
Substantial effort was required to clean the AHUs.
AHUs were substantially disassembled and cleaned using
hand wiping and contact vacuuming. The fan, impeller, and
scroll housing were removed and wet-cleaned using anon-toxic
cleaning fluid. The condensate drain pan, piping, and pumps
were inspected and cleaned as necessary. System filters were
removed and cleaned or replaced. System cooling coils were
wet-cleaned in place using a non-toxic cleaner. Heating coils
were wiped and hand vacuumed.
Table 3. Characteristics of Field Study Test Houses
House
ID#
TH
2
3
4
5
6
7
8
9
House
Age
(yrs)
20
22
18
10
9
28
25
26
35
House
Size
(m2)
121.2
141.2
134.7
183.9
185.8
181.6
92.9
185.8
139.3
# of
Floors
1
1
1
2
2
1.5
1.5
2
2
Duct
Age
(yrs)
20
22
18
10
9
NA
25
26
35
AHU
Age
(yrs)
20
22
0.5
10
9
NA
NA
26
NA
Duct
Material
a
b
c
d
d
b
c
b
b
a - Galvanized sheet-metal ducts with internal fiberglass ductliner
insulation and insulated flexible branch ducts
b - Galvanized sheet-metal ducts with external fiberglass wrap
insulation
c - Galvanized sheet-metal ducts with external fiberglass wrap in
insulation and insulated flexible branch ducts
d - Insulated flixible ducts
NA - Not available
NADCA routinely performed numerous visual inspections
during the cleaning to ensure that the ADC process was
proceeding satisfactorily. Access to the ductwork was
generally through end-caps and flexible duct connections.
Access doors were installed in the ductwork when access to
work areas was difficult. Registers and diffusers were removed
and wet-cleaned using a non-toxic cleaning fluid.
Results
The mechanical ADC methods used were effective in removing
deposited dust deposition from the duct surfaces. Figure 5
shows pre- and post-ADC supply duct deposition levels. Pre-
ADC measurements ranged from 1.0 to 35.1 g/m2, whereas
post-ADC measurements ranged from 0.12 to 1.11 g/m2.
Indoor respirable (PM2 5) and inhalable (PM10) particle mass
concentrations in the houses were relatively low, ranging from
4.2 to 32.7 jWg/m3, consistent with studies in houses without
tobacco smoking. Interpretation of the PM measurement data
was difficult because outdoor concentrations had an apparently
strong influence on indoor concentrations. The outdoor
concentrations varied over the course of each week-long study
making it difficult to determine if the changes in indoor
concentrations after ADC were the result of cleaning or
changes in occupant activities.
Inside IAQ, Spring/Summer 1997
Page 6
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ftf
ft
TH 2 3 4 5 6
House Number
Figure 5. Supply Duct Deposition Levels
A comparison of average pre- and post-ADC bioaerosol levels
showed a reduction in airborne fungi; however, these
reductions are not considered substantial. Initially, the test
houses were not biocontaminated; therefore, a small change
would not be surprising. Pre-ADC airborne fungi levels in the
supply ducts ranged from 14 to 646 colony forming units
(cfu)/m3 while the post-ADC levels ranged from 2 to 300
cfu/m3. Bacteria in samples collected from the surfaces of the
HAC system were highly variable. Pre-ADC bacteria levels
ranged from 5 to 1100 cfu/cm2 in the supply ducts and from 5
to 2300 cfu/cm2 in the return ducts, with a mean of less than
200 cfu/cm2 in most houses. Mean concentrations of return air
bacteria levels were lower after ADC in six of seven houses
measured; however, in the supply ducts, this was true for only
four of the occupied houses. Pre-ADC versus post-ADC
differences were generally small. Fungal levels were generally
higher than bacteria levels and ADC had the most impact on
the ducts with the highest levels of fungi and noticeably
reduced the level of fungi in surface samples collected from
ducts in most houses.
Measurements of system performance factors suggest that
ADC had a positive impact. Because of the small sample size
and the limited duration of the measurements, it is not possible
to quantitatively determine the significance of ADC on system
performance and energy use. Generally it resulted in increased
air flow to the house. Supply air flows increased between 4 to
32% in eight of the houses based on measure-
ments at the floor registers and diffusers in the house. Part of
the increase in supply air flow rates may have been
attributable to minor duct repair. Return air flows measured at
the return air grilles increased 14 to 38% at two houses, but
were not substantially different after ADC at the other seven
houses.
AHU blower motor current increased after ADC in four of the
houses where the measurements were performed. Static
pressure increased in the return air duct at the six houses with
complete measurements. The increase in blower motor current
and in static pressure in the return air ducts suggest improved
system performance. There was no clear trend for changes in
static pressure in the supply ducts or the differential pressures
across the cooling coil. Refrigerant line surface temperatures
did not provide useful information.
Summary
FIAC systems contaminated with dirt and dust are potential
IAQ emission sources. Research shows that FIAC total VOC
emission rates and odors may be effectively reduced by
removing deposition. This field study demonstrated that
mechanical ADC methods can be an effective source
management tool when applied to non-porous bare sheet-metal
ducts. Porous surfaces, such as FGDL, were not evaluated
because houses with FGDL systems, but without visible
surface microbial contamination, were not identified during
selection of the study houses. When FGDL becomes
microbially contaminated, the EPA recommends removal and
replacement rather than any form of ADC. Further research is
required to evaluate ADC effectiveness on porous surfaces.
Differentials in indoor PM levels from pre-ADC to post-ADC
could not be detected. This is consistent with previous research
and is probably due to the strong influence of outdoor PM
sources.
Mechanical ADC methods alone did not substantially reduce
bioaerosol and surface microbial levels; however, surface
treatments such as biocides or encapsulants may be required if
it is determined that substantial reductions are necessary. To
fully evaluate this, future research could include comparisons
using mechanical ADC in combination with surface treatments.
Results of measurements of HAC system-related parameters
suggest that there is a positive impact on HAC system
performance from mechanical ADC. These measured impacts
cannot be considered significant due to the small sample size
and the short monitoring period. Further research would help
substantiate these findings. (EPA Contact: Russell N. Kulp,
919-541-7980, rkulp@engineer.aeerl.epa.gov)
Inside IAQ, Spring/Summer 1997
Page 7
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EMISSIONS FR OM A CID- CA TAL YZED
VARNISHES
Practically all furnishings sold in the U.S. have a coating on
the surface to provide water and stain protection and to
enhance appearance. One type of coating used extensively in
the furniture industry is the alkyd/urea-formaldehyde topcoat.
These are thermosetting resins and are frequently called
conversion varnishes or catalyzed finishes. They do not cure by
drying, as do many coatings, but by a chemical reaction,
creating a durable water- and chemical-resistant coating that
protects the wood during its use.
Conversion varnishes are of interest for ambient air quality
because of emissions during manufacturing. From an indoor air
perspective, these varnishes are of interest because VOCs,
including formaldehyde, may be emitted during use. EPA has
conducted analyses to gain an understanding of the magnitude
of emissions from conversion varnishes and to develop methods
and protocols for testing and analysis of these emissions.
Method
Three conventional conversion varnish systems, coded A, B,
and C, were obtained from three different manufacturers.
Four tests were run:
• EPA Method 24 - Determination of Volatile Matter
Content, Water Content, Density, Volume Solids, and
Weight Solids of Surface Coatings;
• Proposed EPA Method 311 - Analysis of Hazardous Air
Pollutant Compounds by Direct Injection into a Gas
Chromatograph;
• Determination of Free Formaldehyde - Determination of
content in amino resin; and
• Small Chamber Testing - Determination of emission rate
profiles.
The free formaldehyde content of the amino resins was
determined using a method based on the quantitative liberation
of sodium hydroxide when formaldehyde reacts with sodium
sulfite:
HCHO + Na2SO3 + H2O -> NaOH + HOCH2SO3Na.
The small chamber tests were conducted according to the
procedures in ASTM D5116-90, except that alterations were
necessary to accommodate the required high-temperature
drying period specified by the manufacturer for two of the
varnishes. Stainless steel 53-L chambers were used. One
chamber was outfitted with heating jackets. Three
thermocouples were placed inside the chamber to monitor
chamber air, substrate surface temperature, and internal
temperature of the substrate. The chamber air temperature was
monitored in the center of the chamber directly below the
mixing fan. Each test was performed with a temperature
protocol developed using the manufacturer's recommendations
for curing temperatures and times.
The organic solvents used in these varnishes are fairly volatile.
The majority of the VOCs from these solvents are released into
the air within several hours of application. A comparison of
emissions measurements on three different substrates (glass,
oak board, oak veneered hardboard) showed no effect of
substrate on emissions.
Results
The free formaldehyde contents of the three conversion varnish
systems ranged from 1.46 to 5.35 mg/g varnish. Results of
small chamber tests confirmed that the amount of free
formaldehyde (HCHO) initially applied to the surface
represents only a fraction of the total formaldehyde emitted.
Formaldehyde is generated during cure and ageing. For the
three conversion varnishes tested, the total formaldehyde
emissions are 2 to 8 times the amount of free formaldehyde
applied. Varnish B has the highest short-term emission rate,
and varnish C the lowest. Two factors may have contributed to
this result: 1) varnish B has the highest free formaldehyde
content, and 2) higher curing temperatures may accelerate the
emissions.
The long-term emission data show a very different picture. The
decay of the formaldehyde emission rate is a slow process.
Varnish C has the highest rate, but the three varnishes follow
a very similar pattern. Even 3000 hours (125 days) after
application the formaldehyde emission rate is greater than 0.1
mg/m2/hr.
The long-lasting formaldehyde emissions can cause elevated
concentrations in indoor environments. To assess the impact,
we assume that a set of kitchen cabinets is installed in a typical
house (300 m3 volume) with a formaldehyde emission rate of
0.5 mg/m2/hr, which is about the rate at 42 days (1000 hours)
after varnish application. Figure 6 shows the expected
formaldehyde concentrations for various loadings (5 to 20 m2)
and air exchange rates (0.1 to 1.0 air changes per hour). For
example, at 0.5 air exchanges per hour, the indoor
formaldehyde concentration due to cabinets alone could be 16
(jg/m3 (12 ppb) if the source area is 5 m2, and 67 (ig/m3 (50
ppb) if the source area is 20 m2. The irritancy threshold for
formaldehyde is 100 ppb. (EPA contact: Betsy Howard, 919-
541-7915, bhoward@ engineer.aeerl.epa.gov)
Inside IAQ, Spring/Summer 1997
PageS
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400
co
E
,300
-200
d
c
o
O
100 --
0.2 0.4 0.6
Air Exchange Rate (1/hr)
0.8
— 5
m2
-— 10
m2
—
15
m2
+
20
m2
Figure 6. Predicted Indoor HCHO Concentrations in a 300 m3 House Due to Installation of Kitchen Cabinets
With Varnish Applied 1000 Hours Previously
MEASURING TONER EMISSIONS USING
HEADSPACE ANAL YSIS
As part of a larger project to identify pollution prevention
approaches for reducing indoor air emissions from office
equipment (see related article on page 10, "A Large Chamber
Test Method for Measuring Emissions from Office
Equipment"), headspace analyses were performed to evaluate
three toners. The three toners are each manufactured by the
same company in different plants but use the same raw
materials. It was hoped that the results might help to provide
insight into options for developing lower emitting toners. The
headspace tests are simpler and less labor intensive than the
large chamber test method discussed on page 10.
For each headspace test, 50 mg of toner powder was placed in
a 28.3 mL container and allowed to equilibrate for 1.5 hours at
which time a 1 mL headspace air sample was taken for
analysis using a gas chromatograph-flame ionization detector.
Tests were conducted at 150°C which is within the range of
typical fusing temperatures in dry-process photo-
copy machines (100-160°C). Four of the major VOCs
identified in earlier large chamber tests - ethylbenzene, m,p-
xylene, styrene, and o-xylene - were quantified (Table 4).
The headspace concentrations shown in Table 4 show
concentrations from Toners A and B that are typically 2-5
times higher than concentrations from Toner C. According to
the Material Safety Data Sheets, all three toners are composed
of: 80-90% by weight styrene/acrylate copolymer; 5-10% by
weight carbon black; 5-10 % polypropylene wax; 1-3 %
titanium dioxide; and less than 1 % quarternary ammonium
salt.
Toner C is manufactured using the extrusion process.Toners A
and B are manufactured using the Banbury® process. The
extrusion process (Toner C) is more modern and, in addition,
the toner can be manufactured under a vacuum, which may
decrease the amount of VOCs in the toner. These preliminary
results indicate that it may be of value to further investigate the
extrusion process as a potential option for producing lower-
emitting toners. (EPA Contact: Kelly Leovic, 919-541-7717,
e-mail:kleovic@engineer. aeerl.epa.gov)
Table 4. Toner Headspace Concentrations (ng/mL)
Chemical Emitted
Ethylbenzene
/Mjp-Xylene
Styrene
o-Xylene
Toner A
1100
1100
290
740
Toner B
950
930
260
660
Toner C
220
470
130
290
Inside IAQ, Spring/Summer 1997
Page 9
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A LARGE CHAMBER TEST METHOD FOR
MEASURING EMISSIONS FROM OFFICE
EQUIPMENT
Indoor air emissions from dry-process photocopy machines
include: VOCs, ozone, and particles. These emissions can
contribute to adverse health effects such as eye, nose, and
respiratory system irritation, and several are listed as
hazardous air pollutants under the Clean Air Act.
IEMB, Research Triangle Institute, and a group of industry
technical advisors are working together to better understand
indoor air emissions from office equipment so that lower-
emitting equipment can be developed. The project includes: 1)
reviewing the literature on emissions from office equipment
(summarized in Inside IAQ, Spring/Summer 1995,
EPA/600/N-95/004); 2) developing a standard test method to
characterize emissions; 3) measuring emissions from dry-
process photocopy machines using this test method; and 4)
identifying pollution prevention approaches (e.g., source
reduction) for reducing emissions.
Review of the literature showed that no standard test method
exists to evaluate emissions from office equipment, thus
making it difficult to compare the results from different
studies. To address this lack of standardization, a test method
specific to measuring emissions from office equipment was
developed as part of this project. The method was then
evaluated at Research Triangle Institute using four dry-process
photocopy machines. This article covers the test method and
the results from using the test method to evaluate emissions
from the four machines.
Test Method
The test method developed as part of this project uses flow-
through dynamic chambers because they are generally
applicable to all types of equipment and generally mimic
typical use conditions found in an office. Unique
characteristics of the the test method include:
• Chamber Size: The test chamber's linear dimensions must
be a minimum of 1.4 times the dimensions of the
equipment tested in accordance with typical industry
testing procedures.
• Heat Generation: Depending on the machine, heat
generation in the chamber may be a problem. To account
for this, the method specifies a temperature range of 28.5
± 2.5 °C and an air exchange rate of 2 changes per hour.
RH within the chamber is maintained between 30 and 35%.
(A RH of 35% at 31°C represents a mass of water
equivalent to 50% RH at 23°C.)
• Limited Paper Supply: A finite paper supply for copy
machines limits the duration of the test. For this study, a
paper supply of 2000 sheets was used for each test. This
supply was copied after 20 to 40 minutes for the four dry-
process photocopy machines evaluated.
• Toner Carryover: When testing equipment that uses toner,
a toner depletion and replenishment procedure is followed
to avoid carryover of the previous toner between tests.
• Power Requirements: The type of outlet required varies
among copiers. Installation of new outlets, changing
outlets, or multiple outlets may be required.
• Remote Starting: Remote starting of the machines is
necessary to maintain chamber integrity. Problems can be
minimized if an experienced service technician installs, sets
up, and checks out the equipment.
Before placing the photocopy machine in the chamber,
background levels of target pollutants in the chamber air are
measured. A service representative from the manufacturer
serviced and installed the photocopier in the chamber prior to
testing. A toner recommended by the manufacturer was used
for each test, and the same type of paper - containing 20%
recycled materials - was used for all testing. A standard
image, representing about 15% coverage, was used to represent
a typical maximum image for copying.
The chamber air was then measured with the equipment idling
(i.e., powered but not operating) to obtain data on off gassing.
For this study, 2000 copies were copied for each test, and an
integrated chamber air sample was collected from the start of
operation until 2 hours (4 air changes) after the paper supply
was exhausted. The 2000 sheets were copied after 20 to 40
minutes (depending on the machine) for a total sample
collection time of 140 to 160 minutes.
Chamber air concentrations of VOCs were collected with
multisorbent tubes and analyzed by gas chromatograph/mass
spectrometry. Aldehyde/ketone samples were collected on 2,4-
dinitro phenylhydrazine-coated silica cartridges and analyzed
by high performance liquid chromatography. Ozone was
monitored continuously using a DASIBI monitor. Particle
concentrations were monitored continuously for two of the four
machines using a LAS-X optical particle counter.
Results
The estimated emission rates for the four mid-range dry-
process photocopy machines tested in this study are shown in
Table 5. Emissions of VOCs are consistently lower for Copier
4, which uses a mono-component toner, than for the three
machines that use dual-component toners (Copiers 1,2, and 3).
However, emission rates for many of the aldehydes and ketones
are higher for Copier 4. Also, ozone levels for Copier 4 are
higher than for the other three machines tested.
Inside IAQ, Spring/Summer 1997
Page 10
-------
The data presented in Table 4 also show that, although the
same compounds are emitted from all four machines, the
emission rates of these compounds can vary considerably
between machines. For example, the emission rate for
ethylbenzene is 28,000 pg/h for Copier 1 and <50 pg/h for
Copier 4.
Limited particulate data were collected for two of the four
machines tested. Results showed that operation of one of the
machines increased particulate levels to 30 times chamber
background levels for particles smaller than 2 pm in diameter.
Summary
Results of this study have provided valuable information on the
performance of the test method and on emission characteristics
of selected dry-process photocopiers. The testmethod provided
acceptable performance for characterizing emissions from dry-
process photocopy machines. Percent recovery for calculated
emission rates for standard materials emitted into the chamber
at known rates was greater than 85%. Precision of replicate
tests using both standard emitters and photocopiers was good
(less than 10% Relative Standard Deviation). In order to
evaluate the performance of the test method in different
laboratories, a round-robin evaluation in four different U.S.
laboratories was recently performed, and the results will be
presented in a future issue of Inside IAQ.
For the four machines tested in this study, the compounds with
the highest emission rates overall were ethylbenzene (28,000
pg/hour), w,/>-xylene (29,000 pg/hour), o-xylene (17,000
pg/hour), 2-ethyl-l-hexanol (14,000 pg/hour), and styrene
(12,000 pg/hour). To put these results in perspective, chamber
air concentrations of styrene were about 100 pg/m3
for one machine. Since emissions were tested using chamber
conditions that might approximate conditions found in office
buildings, it is likely that the indoor air concentrations of this
magnitude would also be found in offices. (EPA Contact:
Kelly Leovic, 919-541-7717, e-mail: kleovic@engineer.
aeerl.epa.gov)
Table 5. Estmated VOC and Ozone Emission Rates from
Four Dry-Process Photocopiers (pg/h • copier)
Chemical
Ethylbenzene
jw,/7-Xylene
Styrene
o-Xylene
Propylbenzene
2-Ethyl-l-hexanol
w-Nonanal
w-Undecane
Formaldehyde
Acetaldehyde
Acetone
Benzaldehyde
Ozone
Copier
1
28,000
29,000
9,900
17,000
790
230
1,100
2,000
<500
710
2,000
1,800
3,000
Copier
2
360
510
3,000
850
460
5,600
3,900
62
<500
<500
>100
3,800
1,300
Copier
3
2,400
6,100
12,000
4,500
2,100
14,000
3,600
70
2,600
960
>500
2,600
4,700
Copier
4
<50
100
300
<50
<50
130
2,000
103
2,200
1,200
2,800
<100
7,900
GLOSSARY OF ACRONYMS
ACS-Air Conveyance System
ADC-Air Duct Cleaning
AHU-Air Handling Unit
AMSI-Aerosol Mass Spectral Interface
ASTM-American Society of Testing and Materials
A&WMA-Air & Waste Management Association
BEE-Butoxyethoxyethanol
FGDL-Fiberglass Duct Lining
GAC-Granular Activated Carbon
HAC-Heating and Air-Conditioning
HUD-Housing and Urban Development
HVAC-Heating, Ventilating, and Air-Conditioning
lAQ-Indoor Air Quality
lEMB-Indoor Environment Management Branch
MS-Mass Spectrometer
NADCA-National Air Duct Cleaning Association
NRMRL-National Risk Management Research Laboratory
NTIS-National Technical Information Service
OA-Outdoor Air
PFV-Particle Image Velocimetry
PCO-Photocatalytic Oxidation
PM-Particle Mass
RH-Relative Humidity
TH-Test House
VOC-Volatile Organic Compound
Inside IAQ, Spring/Summer 1997
Page 11
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IEMB PAPERS ATENGINEERING SOLUTIONS TO INDOOR AIR QUALITY PROBLEMS SYMPOSIUM
An international symposium, Engineering
Solutions to Indoor Air Quality
Problems, was held July 21-23, 1997, in
Research Triangle Park, NC. The
symposium was cosponsored by APPCD
and the Air & Waste Management
Association (A&WMA) and was attended
by more than 100 participants.
Summaries of the lEMB-sponsored oral
and poster papers presented at the
Symposium follow. Proceedings from the
Symposium will be available from
A&WMA (412-232-3444) in early 1998.
Copies of the IEMB papers should soon
be available from the National Technical
Information Service (703-487-4650).
Characterization of VOC Emissions
From an Alkyd Paint-Tests have been
performed to identify VOCs emitted from
alkyd paint, to characterize the emission
profiles, and to determine the emissions
rates. The approach includes both
analysis of the paint formulation to
identify and quantify VOC concentrations
and dynamic small chamber emissions
tests to characterize the emissions after
application. The predominant
constituents of the paint selected for
testing are alkanes (C9-C12) and C8-C9
aromatics. Primer and paint have been
applied to glass, gypsum, and pine to
assess substrate effects in small chamber
emissions tests. The VOCs in these
solvent-based paints are rapidly emitted
after application, with over 90% of the
target VOCs emitted during the first 24
hours following application. The data do
not indicate any substantial effect of the
substrate on the VOC emissions. In
addition to the alkanes and aromatics,
aldehydes are detected in the emissions
during paint drying. (EPA Contact: John
Chang, 919-541 -3747; jchang@engineer.
aeerl.epa.gov)
Characterizing Sink Effects in Large
Environmental Chambers-lEMB
conducted experiments to characterize the
capacity of a large chamber to absorb and
re-emit VOCs. Test mixtures used were:
1) octane, nonane, decane, undecane, and
dodecane; and 2) ethyl benzene, octanol,
p-dichlorobenzene, decane, dodecane, and
ethylene glycol. This paper presents the
methods used to characterize sink
behavior of the chamber, the results, and
a discussion of the implications for source
characterization using large chambers.
(EPA Contact: Mark A. Mason, 919-541-
4835; mmason@ engineer.aeerl.epa.gov)
Cost Analysis of Activated Carbon vs.
Photocatalytic Oxidation for Removing
VOCs from Indoor ^4/r-The capital,
operating, and maintenance costs were
compared for VOC air cleaning by in-
duct granular activated carbon (GAC)
and photocatalytic oxidation (PCO) units
for new (i.e., non-retrofit) office buildings.
A steady concentration of 1 ppm VOC
was assumed in the indoor air. Even with
the relatively optimistic assumptions for
the PCO system, this analysis suggests
that a VOC air cleaner based on current
PCO technology could have an installed
cost about 10 times higher, and a total
annual operating cost about 2 times
higher than the costs of a comparable
GAC air cleaner. (EPA Contact: D. Bruce
Henschel, 919-541-4112: bhenschel@
engineer.aeerl.epa. gov)
Defining Requirements and Data
Outcomes for Environmental
Verification Program for Indoor Air
Products-Building on existing test
methods, IEMB and Research Triangle
Institute are developing a test protocol for
office furniture as part of EPA's
Environmental Technology Verification
Program. The method will be validated at
Research Triangle Institute and Air
Quality Sciences and then will be
submitted for approval by a stakeholders
group. Results will be provided to clients,
but will also be incorporated in a database
of industry-specific statistical averages
which may be used for modeling pollutant
concentrations within a building. A matrix
of data outcomes such as emission
factors, room concentrations, emission
rates, input for models, time to reach
acceptable level of emissions, exposures,
and risk factors will be developed. (EPA
Contact: Leslie E. Sparks, 919-541-2458;
lsparks@ engineer.aeerl.epa. gov)
Design of an Aerosol Mass Spectral
Interface-An Aerosol Mass Spectral
Interface (AMSI) has been designed and
constructed to chemically characterize
aerosol consumer products. The product
is sprayed into the ASMI, reduced to dry
particles, and passed into the mass
spectrometer (MS) for characterization
for real-time, on-line analysis. Chemical
separation is achieved mass spectrally.
The AMSI can also be operated to
introduce only specific sizes of aerosol
particles into the MS allowing for
chemical characterization by particle size.
The AMSI has been successfully used on
a particle beam MS and on an
atmospheric MS. The ASMI is being
applied to help analyze aerosol consumer
products so that industry can produce
lower-emitting, more efficacious products.
(EPA Contact: Kelly Leovic, 919-541-
7717; kleovic@engineer. aeerl.epa.gov)
Inside IAQ, Spring/Summer 1997
Page 12
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Development of a Digital Optical
Measurement System for Analysis of
Aerosol Spatial Distribution in the
Indoor Environment-A. new technique to
measure aerosol spatial distribution in
realistic rooms is presented. This
measurement system is based on Particle
Image Velocimetry (PFV) which has non-
intrusive, simultaneous, and whole field
measurement features. Tracer particles
and representative aerosols are introduced
into the indoor air, illuminated by a light
sheet, and photographed. The particle
size, a velocity vector map, and
concentration spatial distribution can be
obtained by applying different data
analysis techniques and calibration
procedures. The results from this research
can be used to help understand aerosol
spatial distribution indoors which can be
used to evaluate occupants' exposure to
indoor pollutants and assist manufacturers
in developing more efficacious aerosol
consumer products. (EPA Contact: Kelly
W. Leovic, 919-541-7717, kleovic®
engineer.aeerl .epa.gov)
Investigation of Contact Vacuuming for
Remediation ofFungally Contaminated
Duct Materials-The objectives of this
research program were to: 1) determine,
under constant temperature, RH, and air
flow test conditions, whether fungal spore
levels on HVAC duct material surfaces
could be substantially reduced by
thorough vacuumming; and 2) evaluate
whether subsequent fungal growth would
be limited or contained by a single
mechanical cleaning treatment. Three duct
materials were tested: two new FGDLs
(one containing an antimicrobial
treatment) and one new galvanized steel
duct material. All were artificially soiled.
Results show that notable amounts of
surface dust were removed and surface
spore levels could be reduced in the short-
term on all materials by vacuuming.
However, fungal re-growth occurred
within 6-12 weeks. (EPA Contact: John
Chang, 919-541-3747;
jchang@engineer.aeerl. epa.gov)
Energy Consumption Comparisons for
High Efficiency vs. Low Efficiency
Central Filters-]^ addition to the
increased initial cost associated with a
high efficiency filter as compared to a
standard low efficiency filter, differences
in pressure losses and changes in air flow
associated with various levels of filter
load can impact the energy consumption
of the system. This paper discusses the
results of an analysis of yearly energy
consumption for high and low efficiency
filters applied to a representative
commercial office building located in
three different climatic regions. Using
computer simulation, yearly energy
consumption is estimated for two different
HVAC system types for two of the most
common packaged system sizes. (EPA
Contact: Leslie E. Sparks, 919-541-2458;
lsparks@engineer. aeerl.epa.gov)
Evaluation of Sink Effects on VOCs
from a Latex Paint-The sink strengths
of two common indoor materials, carpet
and gypsum board, were evaluated by
environmental chamber tests using four
VOCs: propylene glycol, ethylene glycol,
BEE, and Texanol. Results indicate that
the sink strengths measured were more
than 1 order-of-magnitude higher than
those for other VOCs previously tested by
EPA. The high sink strengths reflect the
unusually high adsorption capacity of
common indoor materials for the four
VOCs. Results also show that reemission
was an extremely slow process. If all the
VOCs adsorbed were remittable, it would
take more than a year to completely flush
out the VOCs from the sink materials
tested. The long reemission process can
result in chronic and low level exposure to
the VOCs after painting interior walls and
surfaces. (See related article on page 1,
"VOC Emissions From a Latex Paint:
Sink Effects.") (EPA Contact: John C. S.
Chang, 919-541-3747; jchang@
engineer.aeerl. epa.gov)
Fungal Emission Rates and Their
Impact on Indoor ^4/r-Duct materials
were allowed to develop Penicillium and
aspergillus contaminations in a constant
temperature and high RH environment.
Almost no spore release was seen over 6
weeks with a constant 95% RH, while
surface growth increased at least 2 orders
of magnitude. After 6 weeks, the RH was
decreased in 5% increments at 1 hour
intervals. Decreasing RH had little effect
on the emission rate until the RH was
between 60 and 65%, when a spike of
Penicillium was detected. In another
experiment, the impact of HVAC system
cycling was measured on fiberglass duct
liner contaminated with Penicillium. The
RH was set at either 55 or 95%, and the
air flow was 2.5 m/s. At 95% RH, only
periodic spore emissions were detected. At
55% RH a much higher release was
detected. (EPA Contact: John Chang,
919-541-3747; jchang@ engineer.aeerl.
epa.gov)
Identification and Evaluation of
Pollution Prevention Techniques to
Reduce Indoor Emissions from
Engineered Wood Products-Emissions
were screened from four products:
veneered particleboard with sealer and
topcoat; veneered hardboard with stain,
sealer, and topcoat; particleboard overlaid
with vinyl; and particleboard overlaid with
melamine. Total VOCs were highest from
veneered particleboard with sealer and
topcoat. The acid catalyzed alkyd-urea
sealer and topcoat and the particleboard
were the primary emission sources. Three
types of coatings were identified as
potential substitutes: a 2-component
waterborne polyurethane; an aliphatic
urethane acrylate; and a water-based
acrylic. Four types of fiber panels were
identified as potential alternatives for
particleboard: fiber panels made with
medium density fiberboard using
methylene diisocyanate resin; wheat
straw; corrugated cardboard; and
recycled newspaper. (EPA Contact: Kelly
W. Leovic, 919-541-7717,
kleovic@engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1997
Page 13
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Indoor Air Quality Large Building
Characterization Project Planning-
Three buildings were characterized by
examining radon concentrations and IAQ
as affected by building ventilation
dynamics. Measurements included:
carbon dioxide, particle concentrations,
temperature, RH, pressure differentials,
radon (indoor, ambient, and sub-slab),
and outdoor air (OA) intake flow rates.
The OA intake was adjusted when
possible, and fan cycles were controlled
while tracer gas measurements were taken
in all zones. Techniques to vary OA and
pressure differential, and track IAQ were
incorporated into the experimental plan
and are discussed with project rationale.
(EPA Contact: Marc Y. Menetrez, 919-
541-7981; mmenetrez@
engineer.aeerl .epa.gov)
Indoor Emissions from Conversion
Varnishes-Three commercially available
conversion varnish systems were
evaluated. Results confirmed that the
amount of free formaldehyde initially
applied to the surface represents only a
fraction of the total amount of
formaldehyde emitted, implying that
formaldehyde is formed as a result of the
curing reaction. Long-term (133 days)
tests showed a formaldehyde emission rate
greater than 0.14 mg/m2/hr, which can
cause elevated concentrations in indoor
environments. (See related article on page
8, "Emissions from Acid-Catalyzed
Varnishes.") (EPA Contact: Betsy M.
Howard, 919-541-7915; bhoward@
engineer.aeerl .epa.gov)
Large Indoor Air Test Chamber
Characterization-A 30 m3 stainless steel
test chamber is being used by IEMB to
characterize emissions from products and
processes that cannot readily be studied
using small chambers. Initial experiments
have evaluated chamber performance and
the comparability to two other chambers
recently built in Canada and Australia.
Tests have evaluated critical factors that
may influence experiments: 1) the ability
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 different flow
and temperature conditions; and 4)
adsorption of organic compounds by
chamber walls, air ducts, and components
of the air-conditioning system. (EPA
Contact: Betsy M. Howard, 919-541-
7915; bhoward@ engineer.
aeerl.epa.gov)
A Research Plan for Determining the
Penetration of Ambient Particles into
Buildings-Most people receive over 90%
of their exposure to airborne fine particles
indoors. IEMB has begun a study to
determine the relationship between the
outdoor and indoor particle size
distributions and concentrations, and to
determine the factors that affect their
relationship. The study will include a
detailed theoretical analysis of the ways
that particles can enter the indoor
environment and an analysis of the effects
of these entry pathways on the particle
concentration and particle size
distribution indoors. This presentation
will summarize the scientific literature on
relationships between outdoor and indoor
fine particles, the approach being taken to
theoretical analyses of particle
penetration into buildings, and the
approach to the complementary
experimental studies. (EPA Contact:
Ronald B. Mosley, 919-541-7865;
rmosley@engineer. aeerl.epa.gov)
Pilot Air Conveyance System Design,
Characterization, and Cleaning-The
objective of this project was to develop
and refine surface and airborne
contamination measurement techniques
that could be used to evaluate air
conveyance system (ACS) cleaning in
support of a field study to be conducted
later. (See related article on page 6, "Field
Study on Residential Air Duct
Cleaning.") Apilot air conveyance system
using full-size residential HAC equipment
was constructed and operated to provide
a controlled, artificially soiled, ACS
environment. Three types of duct systems
were evaluated with the proposed
measurement methods under unsoiled and
soiled conditions. Each duct system was
then cleaned by professional ACS
cleaners and reevaluated. As a result of
the pilot study, the surface contamination
measurement methods were evaluated
over a range of conditions and improved.
Surface contamination (microbial and
total dust) measurements and visual
inspections showed that the pilot unit was
effectively cleaned by the methods
applied. Submicron and larger particle
counts were reduced following ACS
cleaning, and respirable particle mass was
reduced for two of the three duct systems
used. (EPA Contact: Russell M. Kulp,
919-541-7980; rkulp@engineer.
aeerl.epa.gov)
Pilot Study to Evaluate the Impact of
Air Duct Cleaning on Indoor Air
Quality in Residences-A nine-home pilot
study was performed to evaluate the
effectiveness of air duct cleaning
methods, to test sampling and analysis
methods that might be used to measure
the impact of air duct cleaning on IAQ
and energy use, and to collect an initial
data set in occupied residences. (See
related article on page 6, "Field Study on
Residential Air Duct Cleaning") (EPA
Contact: Russell M. Kulp, 919-541-7980;
rkulp@engineer. aeerl.epa.gov)
Inside IAQ, Spring/Summer 1997
Page 14
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Reducing Solvent and Propellant
Emissions from Consumer Products-
The development of a spray dispenser
that removes the need for VOC solvents
and hydrocarbon propellants, replacing
them with water and air, respectively, is
discussed. Maintaining, or improving,
spray performance using such a dispenser
requires insensitivity to the increases in
product viscosity and surface tension that
result from replacement of alcohol by
water. It also requires a dispenser that
consumes considerably less propellant
since air (a gas) will be substituted for a
hydrocarbon (liquid) without an increase
in container volume or pressure rating.
Such a dispenser was designed by
researchers at Purdue. Results for a
variety of liquid viscosities and surface
tensions spanning the range of current and
anticipated consumer products are
included. (EPA Contact: Kelly W.
Leovic, 919-541-7717, kleovic@
engineer.aeerl .epa.gov)
Research Agenda on Air Duct
Cleaning-Duct cleaning practices
include: source control by removal of
contaminants from the air ducts and
related HVAC system components;
application of antimicrobial agents to kill
bacteria and fungi; encapsulants and
sealants to contain imbedded
contaminants; and the introduction of
ozone to mask odors and kill
microbiological organisms. In addition to
the direct costs of acquiring duct cleaning
services, long-term costs or savings may
be experienced by the consumer due to
duct-cleaning-related changes in energy
use and health care expenditures. Four
priority research areas are discussed for
the purpose of reducing risk and pollutant
exposure: source removal/control
techniques; application and use of
antimicrobial agents; HVAC system
sealants/ encapsulants; and use of ozone
in ventilation systems. (EPA Contact:
Russell M. Kulp, 919-541-7980; rkulp@
engineer.aeerl .epa.gov)
RISK - An IAQ Model for Windows-
RISK, a computer model for calculating
individual exposure to indoor air
pollutants from sources, is presented.
The model calculates exposure due to
individual, as opposed to population,
activity patterns. Source emissions
models include empirical first and second
order decay and mass-transfer models.
The model allows for consideration of the
effects of room-to-room air flows, air
exchange with the outdoors, and air
cleaners on the concentration/time history
of pollutants. Comparison of model
predictions with data from experiments
conducted in lEMB's IAQ test house is
discussed. The model predictions are
generally in good agreement with the test
house measurements. (EPA Contact:
Leslie E. Sparks, 919-541-2458,
lsparks@ engineer.aeerl.epa.gov)
Round-Robin Evaluation of a Test
Method to Evaluate Indoor Air
Emissions From Dry-Process
Photocopiers-A. test method for
measuring emissions from office
equipment and a specific version of the
method for the evaluation of dry-process
photocopy machines were developed.
Because different test chambers may not
perform similarly because of sink effects,
temperature and humidity control, air
exchange, and pollutant monitoring, a
"round-robin" evaluation was performed
in four U.S. laboratories. Results
demonstrate that the test method
developed can be used successfully in
different chambers to measure VOCs
from dry-process photcopiers. Excluding
problems with suspected analytical bias
observed from one of the laboratories, the
precision between laboratories was
excellent with relative standard deviations
below 10% in most cases. (EPA Contact:
Kelly W. Leovic, 919-541-7717,
kleovic@ engineer.aeerl. epa.gov)
SUMMARIES OF OTHER 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.
Characterization of Emissions from
Conversion Varnishes-Emissions from
three commercially available conversion
varnish coating "systems" (stain, sealer,
and topcoat) were measured.
Formaldehyde emissions were 6-7 times
the free formaldehyde content, indicating
that the formaldehyde is formed during the
curing process. Results of formulation
analyses and emission tests are described
in this paper. Source: Proceedings: The
Emission Inventory: Key to Planning,
Permits, Compliance and Reporting, New
Orleans, LA, September 4-6,1996. (EPA
Contact: Elizabeth M. Howard, 919-541-
7915, bhoward@engineer.aeerl.epa.gov)
Effects of Fan Cycling on the Particle
Shedding of Particulate Air Filters
Used for IAQ Control-Loaded fiberglass
and synthetic organic media bag filters
were tested in a laboratory test duct for
total particle and bioaerosol shedding as
the fan cycled off and on. No measurable
particle shedding was observed due to fan
cycling. Source: Proceedings of Indoor
Air'96. (EPA Contact: Russ N. Kulp,
919-541-7980, rkulp@
engineer.aeerl .epa.gov)
(Continued on Page 16)
Inside IAQ, Spring/Summer 1997
Page 15
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Reducing Indoor Air Emissions from
Dry-Process Photocopy Machines-
Emissions from dry-process photocopy
machines include :VOCs, ozone, and
particles. A number of the compounds
emitted can contribute to adverse health
effects such as eye, nose, and respiratory
system irritation, and several are listed as
hazardous air pollutants under the Clean
Air Act. Through measuring emissions in
a large chamber, reviewing the literature,
and interacting with industry, a number of
potential pollution prevention approaches
for reducing emissions from dry-process
photocopy machines have been identified:
1) formulating toners using high purity
raw
materials and state-of-the-art manufact-
uring processes; 2) using a charged roller
system (rather than electrically charged
corona wires) to reduce ozone emissions;
3) minimizing the need for and/or
improving equipment maintenance to
improve machine performance; 4)
reducing temperature of the fusing
operation to reduce the VOC volatilization
from the toner; and 5) improving transfer
efficiency of the toner to the paper to
minimize toner emissions. Source: In
proceedings of Healthy Buildings/IAQ
'97, Washington, DC, Sept. 27 - Oct. 2,
1997. (EPA Contact: Kelly W. Leovic,
919-541-7717, kleovic@engineer.aeerl.
epa.gov)
Update on EPA's Air Duct Cleaning
Research Activities-The paper focuses on
the IEMB/NADCA pilot field study
conducted in nine homes during the
summer of 1996 (see related article on
page 6, "Field Study on Residential Air
Duct Cleaning"). The objectives of the
study were to collect information on: 1)
the effectiveness of currently available air
duct cleaning methods used on residential
heating and air-conditioning systems, 2)
the impact of air duct cleaning on
residential IAQ, and 3) the impact of air
duct cleaning on energy usage. Source: In
proceedings of Indoor Environments '97
Symposium, "Setting the Standard for
Healthy Building Management," held in
Baltimore, MD, April 7-9, 1997. (EPA
Contact: Russell N. Kulp, 919-541-7980,
rkulp@engineer.aeerl.epa.gov)
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-97/003, Spring/Summer 1997
An Equal Opportunity Employer
FIRST CLASS MAIL
POSTAGE AND FEES PAID
EPA
PERMIT No. G-35
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