United States Environmental
                    Protection Agency	
                        Office of Research and Development
                        Research Triangle Park, NC 27711
                                                            EPA/600/N-99/002 Spring/Summer 1999
 &EFA
Inside   I A Q
        EPA's Indoor Air Quality Research Update
              Engineering Solutions to
            Indoor Air Quality Problems
                    Symposium
                  July 17-19, 2000
                    Raleigh, NC
           (See Page 11 for Call for Papers)
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                In This Issue
Page
                Fungal Spores and the Influence of Humidity,

                  Velocity, and Amplification on Emission Rates	1
                Evaluation of Potential P2 Approach

                  for Reducing Photocopier VOC Emissions 	4

                Testing of IAQ Simulation Software  	5

                Evaporative Emissions in Ventilated Rooms	6

                Summaries of Recent Publications	8

                Glossary  	10

                Call for Papers  	11
FUNGAL  SPORES  AND  THE  INFLUENCE  OF
HUMIDITY,  VELOCITY, AND AMPLIFICATION  ON
EMISSION RATES

Although a significant amount of work has been done to
elucidate the  conditions under which fungi will grow on
material surfaces,  little information  is available  that
quantitatively relates surface  concentrations  to  airborne
concentration and ultimately exposure. This article discusses
the impact of relative humidity (RH), air velocity, and surface
growth on the  emission rates of fungal spores from the surface
of contaminated material.

The two factors that were anticipated to have the most impact
on emissions  were air velocity and RH. RH  controls the
release of spores by some fungi.  High RH is important for
those active release mechanisms that depend on the rupture of
turgid cells, while tissue desiccation in low RH is important to
another class  of release mechanisms.  The velocity of air
                flowing over fungal colonies is known to be important to
                dissemination both as a source of energy for liberation and to
                enhance mass transport for humidity-driven processes.

                In previous experiments, we found that fungal emissions were
                influenced by  complex  interactions among  RH, surface
                growth, and material characteristics. RH has a tremendous
                impact on  the dissemination  of  both Penicillium  and
                Aspergillus  spores.  Under the high RH conditions where
                growth occurred, there was  little or no  release of spores.
                However, as the RH was  lowered, spore  release  was
                triggered. While the data are limited to these few cases, the
                potential impact of the  results on current control  and
                remediation practices was profound. Lowering uncontrolled
                RH is almost always a recommended practice. The data in
                this study point out that during remediation this could be the
                wrong  strategy and could  lead to increased  short-term
                emissions.
                               (Continued on Page 2)
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The objectives of this study were to: 1) initiate experiments
relating surface load or concentration (for new growth) to the
emission of fungal  spores, and 2) measure the impact of air
velocity at a variety of RHs. The experiments were conducted
in the Dynamic Microbial Test Chamber (DMTC).  The
DMTC is  a  room-sized  test facility designed to conduct
studies  on the conditions  and  factors  that  influence
biocontaminant emissions and dissemination. It is a cube with
inside dimensions of 2.44 m, stainless steel walls  and floor,
and an acrylic drop-in ceiling. Temperature (18-32°C) and
RH control (55 to 95%) are provided through an air handler
unit (AHU) with an air circulation rate between 1.4 and 4.8
mVmin.

The chamber was adapted to contain eight miniducts as shown
in Figure 1. The blower forces the conditioned DMTC air into
a High Efficiency Particulate Air (HEPA) filter, from which
the air for the  eight miniducts is obtained. The channel design
was chosen for the  miniducts to limit the total amount of air
required for a single test, allowing  multiple tests  to be run
simultaneously, and simulate  flow  conditions in a heating,
ventilating, and air-conditioning duct.

Three newly purchased common duct materials were studied:
two fiberglass duct  liners  (FDL-A and FDL-B)  and  one
fiberglass ductboard (FGD). In appearance, these duct liners
were very similar, with an uncoated surface intended to be
attached to a rigid duct material and a polymer coated surface
intended to be in contact with the moving air in the duct. FDL-
B contained a permanent (bound) antimicrobial in the coating
of the  airstream surface.  Penicillium chrysogenum  and
Aspergillus  were   selected  as  the  test  organisms.  P.
chrysogenum has been reported as one of the most frequently
isolated molds from the air, housedust, and surfaces of indoor
environments, and has been isolated from a number of air-
Inside IAQ is distributed twice a year and highlights indoor air
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Figure 1. Dynamic Microbial Test Chamber.

conditioning systems in environments where patients were
suffering from allergic disease. The materials were artificially
soiled and then inoculated in an aerosol deposition chamber.
The   targeted  amount   of  dust   for  deposition  was
approximately 100 mg dust/100  cm2. This level has been
considered moderately soiled in previous experiments and
was selected to relate these data to previous experiments.

After artificial soiling and inoculation, the 30.5 x 91.4 cm (1
x 3 ft) pieces of test material were placed in the miniducts.
Temperature  and  RH  throughout  the miniducts  were
maintained at 23.5 ° C and 94%, respectively. The air velocity
through the miniducts was 2.5 m/s (500 ft/min). At the start
of an emission rate determination, the chamber  RH was
lowered from 94% to the test RH (i.e., 64%) by lowering the
RH setting on the AHU. Six isokinetic,  1-hour air samples
were collected using the Mattson-Garvin slit-to-agar sampler
for culturable bioaerosols. At the completion of each sixth
hour sample, chamber RH was returned to the maintenance
RH of 94%. No experiments  were performed within 2 days
of any other to allow the surface of the materials to recover
from the decreased RH and to make certain the starting point
for all emission measurements was the same. Surface samples
were collected at weekly intervals, at least 1 day  after the
bioaerosol sample was collected.

Colony forming units (CPUs) were counted shortly after visible
growth was first noted and again as moderate growth became
apparent.  To calculate the emission rates, the CPUs on the
Mattson-Garvin plates were identified and enumerated, and the
Inside IAQ, Spring/Summer 1999
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CFUs/min were determined. The value was adjusted for the total
flow rate and divided by the area of the emitting surface.

Figure 2 shows the impact of surface load during log-phase
growth on the emission rates of fungal spores from the surface
of the duct material using A. versicolor as the test organism.
The test material, FDL-B, was inoculated with two different
concentrations of A.  versicolor. Emissions were measured at
64% RH. The columns represent  surface  growth and  are
referenced to the left axis as Log10 CPU/10 cm2. The two
levels of inoculum used are denoted  as lower and higher. The
lower inoculum was approximately  102 CPU/10 cm2, and the
higher inoculum was approximately 103 CPU/10 cm2. Error
bars are included for weeks 0 and 1 to show that no significant
difference was measured between the levels of surface growth
after the initial inoculation.  The lines  represent the spore
emissions results and are plotted on a log scale against the
right axis as CFU/m2/min. None of the differences between the
emission rates were significant except at week 3  (see error
bars). When comparing the surface  and the emission data, it
is apparent that, for A.  versicolor under these conditions,
surface load directly influences the emission rate. In  other
words, as the  surface concentration of organisms increased
during log-phase growth, the emission rate increased until a
stable  population was  reached, and then the  emissions
appeared to remain essentially constant.
Table 1. Emission (CFU/m2/min) of P. chrysogenum spores
at four different airflow rates and RHs.
Figure  2. Surface  growth vs.  spore  emissions  for A.
versicolor at lower and higher inoculum levels.

Tables 1 and 2 present the first hour emission rate for P.
chrysogenum and A. versicolor, respectively.  The  surface
concentration was monitored  to document that a stable
population of organisms had been established on the surfaces
of all the materials for at least 12 weeks.
MATERIA
L
FDL-B
FDL-A
FGD
RH
%
64
70
84
94
64
70
84
94
64
70
84
94
AIRFLOW, m/sec.
0.5
9
5; 1
1
2
610
27;7
0
26
13
8;1
1
17
1.0
13
28
1
5
155
30
25
7
20
6
0
0
1.5
409
228
59
124;127
465
229
234
145; 75
88
17
50
0
2.5
804; 2023; 1249
972; 1480
150
81
813; 2392; 1501
710; 1385
287
69
333; 854; 267
335; 162
12
47
Table 2. Emission (CFU/m2/min) of A. versicolor spores at
four different airflow rates and RHs.
MATERIAL
FDL-B
FDL-A
FGD
RH
%
64
70
84
94
64
70
84
94
64
70
84
94
AIRFLOW, m/sec.
0.5
1
0; 1
0
2
24
ii;
2
1
0
0
0;0
1
2
1.0
11
1
1
0
44
26
0
0
4
5
0
0
1.5
45
25
0
0;0
52
17
10
0;7
138
66
0
0;0
2.5
170; 100; 190
60; 20
0
11
43; 15
8; 14
3
20
567; 151; 543
242; 182
22
0
The first column lists the three different materials tested, and
the second column lists the four RHs at which the emissions
were measured. The final four columns show the emission
rates for the two test organisms at the four airflows used in
the study. In a number of cases (e.g., FDL-B, 64% RH at 2.5
m/s),  multiple  values, separated  by a  semi-colon,  are
reported. These values are  replicate measurements from
different experiments. In general, these data are in good
agreement.

As shown previously, the emission rates were inversely related
to the RH at airflows of 2.45  m/s. In other words, as the RH
decreased, the emission rate increased. The current experiment
generally confirms that relationship at the lower airflow rates.
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 However, once the emission rate becomes too low, the natural
variability overwhelms our ability to measure a difference.

When the data from the different airflows are compared, the
emission rate is related  to  the flow  rate  across   the
contaminated surface. As the flow rate increases, so do the
emission rates. This was seen at all four humidities included
in the study. Overall, the emission rates were notably lower
for the A. versicolor than the P. chrysogenum  regardless of
RH or airflow.

While additional research will be required to relate these data
to exposure, the emission rates measured in these experiments
support data from our previous  study,  and modeling the
results  shows that the  emission  rates  produced room
concentrations consistent with field observations reported
from the literature.

In summary, the results show a complex interaction of factors.
For a limited data set, emission rates are inversely proportional
to RH, but directly related to airflow and surface loading. This
work  was performed by Research Triangle Institute under
cooperative agreement number 000000. (EPA Contact: Marc
Menetrez, 919-541-7981, menetrez.marc @epa.gov)
EVALUATION OF  POTENTIAL  P2  APPROACH
FORREDUCING PHOTOCOPIER VOC EMISSIONS

This project is  studying  the  potential for reducing the
emissions of volatile organic compounds (VOCs) from office
photocopy  machines, through  modifications to the  raw
materials or the manufacturing process used in producing the
toners used in these machines.

In an earlier EPA report (EPA-600/R-98-080), concentrations
of selected VOCs were reported in the head space (static)
above samples from three lots of nominally identical toners,
raised to temperatures as high as 150 °C (the lower end of the
range  at which the copier  fusing  mechanism typically
operates). According to the manufacturer, these three toner
lots nominally had the same chemical composition, and were
manufactured for use in the same copy machine. Yet the
samples from one of the lots consistently provided head-space
concentrations 50 to 80% lower than those from the other two
lots, for each of four specific hazardous  organic compounds
that were measured. The four VOCs - styrene, ethylbenzene,
o-xylene, and m,p-xylene - are likely impurities resulting from
the polymer used in manufacturing the toners.

In the earlier report, it was  noted that the toner lot producing
the lower head-space concentrations had been manufactured
using a continuous extrusion process, whereas the other two
had been manufactured at different facilities using a batch
process involving  Banbury  mixers.  No  information  was
available regarding  the  purity  of  the specific polymer
feedstocks used in these manufacturing processes at different
sites.

A follow-on study is now underway to better define the extent
to which modifications to  the toner  manufacturing process
might  offer pollution  prevention  (P2) opportunities for
reducing VOC emissions from photocopiers. This follow-on
effort initially involves head-space testing on toner samples,
as did the earlier effort discussed above, but addresses a
larger  number of samples  in an effort to systematically
separate out the effects of the different variables that could be
impacting the observed results. These variables include:

\) Manufacturing process.  Three processes  appear to be
  commonly employed: continuous extrusion under vacuum;
  continuous extrusion at atmospheric pressure; and batch
  mixing (e.g., using a Banbury mixer).
2) Purity of the feedstock polymer.
3) Time at which the toner sample was collected during the
  manufacturing run. At issue is the inherent variability in
  toner characteristics over the course of a given run, with
  a fixed process and feedstock.
4) Manufacturer and/or the machine for which the toner is
  being produced (which would impact the nature of the
  polymer and chemical composition of the  toner). If the
  manufacturing process or the feedstock purity is having a
  major impact on VOC emissions, is this impact consistent
  between vendors and toner types?

This study will address specific VOCs, in addition to the four
listed above, if other compounds are also found at high levels
in the head space.

If the results from this head space testing define an important
and consistent impact of one or more variables on head space
VOC levels, the study may be  extended to include small
chamber  testing of  VOC  emissions from  copied paper
produced by a machine using both the lower- and the higher-
emitting toners.  The objective would be to assess the extent
to which  the lower-emitting toners  would  reduce VOC
emissions into the office space from copied paper after it has
left the photocopier room.  (EPA Contact: Bruce Henschel,
919/541-4112, henschel.bruce@epa.gov)
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TESTING OF IAQ SIMULATION SOFTWARE
An IAQ simulation software package, tentatively named the
Simulation Tool Kit for Indoor Air Quality and Exposure or
STKi, has recently started its beta test. STKi is a collection of
Microsoft Windows-based IAQ simulation programs with
similar user  interfaces.  It  consists of a general-purpose
simulation program and a  series of stand-alone, special-
purpose simulation programs.

The general purpose simulation program is designed to give the
user  the  flexibility to  simulate a wide range of indoor air
pollution scenarios. It is capable of making multi-zone and multi-
pollutant simulations and allows gas-phase chemical  reactions.

The  special purpose  simulation programs deal with mass
transfer models. In recent years, modeling of indoor sources
has gradually shifted from simple, statistical models to more
complex,  fundamentally based models. While the latter
provide improved accuracy and validity, their usefulness has
been hindered by their increased complexity.  Potential users
may want to avoid unfamiliar equations and  the tedious
calculations behind them.  The  special-purpose simulation
programs in STKi help resolve this problem by shielding the
users from mathematical  details  and  allowing  them  to
concentrate on lAQ-related issues.

An array of good IAQ  simulation programs have been
developed and  some can be  easily obtained.  STKi  is not
designed  to replace them.   Instead, it complements and
supplements them. STKi is targeted mainly for  advanced
users, those who are  directly involved in  IAQ  exposure
estimation, risk  assessment, or IAQ research. STKi is not an
expert system. It is the user's responsibility to determine what
model parameters to choose. Several emissions databases are
being developed  in  Europe  and  North  America.  Those
databases plus other sources can be useful tools in parameter
selection. STKi  does not predict the air movement inside a
building,  either. However, it does allow the user to input the
airflow data from existing air infiltration or computational
fluid dynamic models. The first public release of STKi is
expected  in the winter of 1999 and will include the five
programs shown in Table 3.
Table 3. Programs included.
Carpet.EXE
GPS.EXE
PM.EXE
Spill.EXE
VBX.EXE
a model for VOC emissions from new
carpet
general-purpose simulation program
a model for indoor paniculate matter
models for indoor solvent spill
models for predicting VOC emissions from
solvent-based indoor coating materials based
on product formulation
The  whole package  will be  developed in a cumulative
manner. More special-purpose programs will follow. Some
candidate programs currently under consideration are listed
in Table 4.
Table 4. Programs
proposed.
Chem. EXE
Latex.EXE
Pest.EXE
Water.EXE
WBC.EXE
model shell for indoor air chemistry
latex paint emission models
fugacity models for indoor application
of pesticides
models for VOC emissions from water
use (e.g., shower, washing machine,
and dish washer)
models for water-based cleaners (liquid
pool and wet film)
We welcome input from potential users, especially about their
needs and the programs they would like included. (EPA
Contact: Zhishi Guo, 919-541-0185, guo.zhishi@epa.gov)
Inside IAQ, Spring/Summer 1999
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EVAPORATIVE  EMISSIONS  IN  VENTILATED
ROOMS

VOCs are emitted from building materials, especially in many
new buildings. Emissions occur  in  a chainlike process:
diffusion inside the emitting material; crossing the surface-air
interface; transport across the mass transfer boundary layer;
and mixing into the bulk air. In any particular material, one of
these processes may be rate controlling. For freshly applied
liquid films, emissions are generally controlled by evaporation
from the surface and depend on local airflow parameters such
as temperature and velocity.

Experiments at different air velocity levels were performed in
a full-scale ventilated chamber to investigate the influence of
local airflow on evaporative emissions from a surface. The
experiments included velocity measurements of the flow over
the surface and measurements of chamber air concentrations.
The research was conducted in lEMB's large chamber by
Claus Topp of Aalborg University and was supported by the
Danish Technical Research Council.

Experiments were performed at EPA in a full-scale ventilated
chamber (4.0 x 2.8 x 2.6 m; 29 m3).  Four slots provide
supply air to the chamber, one at the foot of each wall. Three
of the inlet slots direct the flow upward along the wall, and the
fourth inlet slot directs the flow along the floor. The return is
located at the center of the ceiling.

The experiments were performed at two different velocities
with temperature and RH kept fixed. In all experiments, the
air exchange rate was 1 air change per hour (ACH), and the
amount of recirculating air was changed to obtain different
velocity  levels in the chamber.  Two experiments were
performed at a total supply flow rate of 5 ACH (recirculation
rate of 4  h"1), and two experiments were performed at a total
supply flow rate 2 ACH (recirculation rate of 1 h"1).

In each of the experiments, a 1.48 m2 wood board was placed
at the center of the chamber floor. After conditioning, pure
decane (C10H22, equilibrium vapor pressure Cv= 12115 mg/m3
and molecular diffusion coefficient D = 0.0207 m2/h) was
applied to the top surface of the board. Smoke tests showed
that the flow over the wood board was parallel to the surface.
Velocity profiles were measured to obtain detailed knowledge
of the boundary layer flow over the wood board. The profiles
were measured with a hot-wire anemometer at the center of the
wood board and at 250 mm east, west, north, and south of the
center, respectively. The  airflow in the chamber was from
east to west.
The  concentration of  decane in the chamber air was
determined by gas chromatography. Chamber air was pulled
through sorbent traps at a known flow rate using mass flow
controllers and  a vacuum pump.  Analytes were extracted
from the traps with carbon disulfide (CS2), and the con-
centration of decane in the  extract was determined by
injecting a subsample of the extract onto the column of a gas
chromatograph equipped with a mass selective detector.

The velocity profiles over the wood board are shown in
Figures 3 and 4, for 2 and 5 ACH, respectively. As expected,
the maximum velocity decreases with distance from the inlet.
The velocities at the north and south locations, though, are
somewhat different indicating that the flow is not symmetric
around the board. The difference increases with the flow rate.
For 2 ACH, the maximum velocities occur approximately 3
cm above the surface and, for 5 ACH, they occur 2 cm above
the surface. As the flow rate  is decreased, the maximum
velocities drop accordingly as shown in Table 5.

Table 5. Maximum velocities over the wood board.
ACH
2
5
Center
(m/s)
0.27
0.78
East
(m/s)
0.32
0.86
West
(m/s)
0.22
0.64
North
(m/s)
0.23
0.91
South
(m/s)
0.17
0.29
           0.00    0.10   0.20   0.30   0.40
                   Velocity (m/s)
           Figure 3. Velocity profiles over the
                wood board for 2 ACH.
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            150
                                                          Table 6. Mass transfer coefficients from non-linear
                                                                   regression.
              0
               0.00  0.20  0.40  0.60   0.80  1.00
                       Velocity (mis)
           Figure 4. Velocity profiles over the
                wood board for 5 ACH.
Measurements of chamber concentrations overtime show that
chamber concentration reaches its maximum after approxi-
mately 0.5 h for 2 ACH and after 1 h for 5 ACH. Then the
concentration drops rapidly within 10 h. In the early stage of
the emission process, there is a significant difference between
concentrations from one  velocity level to another but after
approximately 2 h the concentration levels are very similar. In
general, there  is good agreement between the experimental
data and the model predictions using the mass transfer model
developed by IEMB, but the model seems to predict  lower
peak concentrations. Concentrations from experiments with
the same total supply flow rate are very similar although there
is  a  10 % difference between the peak  concentrations for 2
ACH. For 5 ACH, there is a difference of 12 % in the amount
of VOC applied but the difference in concentration is not as
significant.

The  emission rate can be  conveniently expressed in terms of
a mass transfer coefficient as shown in Table 6.The standard
deviations from the regressions are within 12 %, which is
satisfactory. The mass transfer coefficients from experiments
with identical flow rates agree within 10 %.
Experiment
1
2
3
4
ke
(m/h)
10.29
11.07
4.01
3.64
Std.Dev.
(m/h)
0.84
1.29
0.19
0.21
Std. Dev
(%)
8.2
11.7
4.7
5.8
Results also show that emissions, expressed in terms of the
mass transfer coefficient, increase  with velocity for fixed
temperature, RH, and air exchange rate. This emphasizes the
importance of testing materials at the correct velocity and
turbulence level in order to obtain the actual emission rate for
a given product.

As noted, the results agree with the IEMB model predictions
and show that, after reaching its maximum, the chamber
concentration drops rapidly within 10 h, which is consistent
with previous results obtained by IEMB. IEMB studied the
emission characteristics of a mixture of organic compounds,
including decane,  and concluded  that the first phase of the
emission process is controlled mainly by evaporation from the
surface. After  that, the decay rate  slows  as  diffusion
transport  inside  the material becomes  the  controlling
mechanism of the  emission process.

In summary, two  experiments were  performed  at  each
velocity level, and the results are consistent, indicating a high
level of repeatability. It was found that the  velocity level in
the boundary layer flow over the surface has a strong impact
on  the mass  transfer coefficient  as the mass  transfer
coefficient  increases in proportion to the velocity.  This
emphasizes the importance of testing materials at the correct
velocity and turbulence level to overcome scaling problems
when transferring  results from a small-scale test chamber to
a full-scale ventilated room. (EPA Contact: Les Sparks, 919-
541-2458, sparks.les@epa.gov)
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                               SUMMARIES OF RECENT PUBLICA TIONS
Controlling Souces of Indoor Air
Pollution Through Pollution Preven-
tion - This paper  overviews  recent
research  on  the  application  of  P2
techniques  for  improved  IAQ:   1)
developing methods and tools that can
be  used  to evaluate emissions from
equipment or products; 2) developing
generic  P2 solutions;  3) identifying
high-emitting raw materials or compon-
ents of products; and 4) evaluating low-
emitting materials. Test method guide-
lines  for measuring emissions from
office equipment were  developed and
then evaluated by  testing  four dry-
process copiers in one chamber and by
conducting a four-laboratory evaluation
using one of the copiers. For aerosol
consumer  products,   measurement
methods  and  models were developed
that can be used to belter understand
aerosol   behavior  so that   more
efficacious and less toxic products can
be developed.  A generic,  innovative
spray nozzle for use with precharged
aerosol containers was  developed and
evaluated. The new design allows  for
the reformulation of selected aerosol
consumer products using water and air
in place of  VOC solvents and hydro-
carbon propellants, respectively. High-
emitting components of common types
of finished  engineered wood products
were identified by evaluating emissions
at each  stage of the  manufacturing
process. Three fiber panels  and three
coatings  were  then   identified   as
potential  low-emitting  alternative
materials. Four types of printed circuit
board  laminates   were  evaluated.
Glass/epoxy laminates and glass/lignin-
containing  epoxy  resin   laminates
emitted fewer volatile compounds than
the two  paper/phenolic  resin-based
laminates. Source: Proceedings of the
ASHRAE Conference, "IAQ & Energy
'98. Using ASHRAE Standards 62 and
90.1 to Provide Acceptable Indoor Air
Quality and Energy Efficiency" (EPA
Contact:  Kelly W.  Leovic,  919-541-
7717, leovic.kelly@epa.gov)
Emissions  of Odorous  Aldehydes
from Alkyd Paint - Odorous aldehyde
emissions from a commonly used alkyd
paint were measured and characterized.
Initial formulation analysis indicated no
measurable  aldehydes  in  the  liquid
paint.  However, small  environmental
chamber tests showed  that, for each
gram of the alkyd paint applied, more
than  2  mg  of  aldehydes  (mainly
hexanal) were emitted during the curing
(drying) period. The emission profiles
of aldehydes were very different from
those of other VOCs such as alkanes
and  aromatics. Since no measurable
aldehydes were found  in the original
paint, it is suspected that the aldehydes
emitted were produced by autoxidation
of the  unsaturated fatty acid esters in
the alkyd resins. It was found that the
hexanal emission rate can be simulated
by a mathematical model assuming that
the autoxidation process was controlled
by a consecutive first-order reaction
mechanism. The mathematical model
was  used  to  predict the  indoor  air
hexanal concentrations for a typical
application of the  alkyd paint tested.
The  result indicated that the aldehyde
emissions  can result  in   prolonged
(several   days)   exposure  risk   to
occupants. The occupant exposure to
hexanal emitted from alkyd paint also
could cause sensory irritation and other
health  concerns.    Atmospheric
Environment, 32,20,3581-3586,1998.
(EPA Contact: John Chang, 919-541-
3747, chang.john@epa.gov)
Estimation  of  the  Rate  of  VOC
Emissions   From  Solvent-Based
Indoor Coating Materials Based on
Product  Formulation  -  Two  comp-
utational  methods are proposed  for
estimation of the emission rate of VOCs
from  solvent-based  indoor  coating
materials based on the knowledge of
product formulation.  The first method
utilizes two previously developed mass
transfer  models  with   two   key
parameters  ~ the total vapor pressure
and the average molecular weight for
total  volatile  organic  compounds
(TVOCs) ~ being estimated based on
the VOC contents in the product.  The
second method is based on a simple,
first-order  decay model  with  its
parameters  being estimated from the
properties of both the source and the
environment. All the model parameters
can  be  readily  obtained.   Detailed
procedures   for  computing  the  key
parameters   are  described by using
examples.  The predictive errors were
evaluated with small chamber data, and
the results were satisfactory. Thus, the
proposed methods provide a way to
predict the VOC emissions in the indoor
environment without having to conduct
costly  chamber testing.    The  two
proposed  methods   work  for  both
TVOCs and  individual VOCs.  Pros
and cons for each method are discussed.
Source:  Atmospheric  Environment,
Vol. 33, No.  8, pp. 1205-1215, 1999.
(EPA Contact: Zhishi Guo, 919-541-
0185, guo.zhishi@epa.gov)
Inside IAQ, Spring/Summer 1999
                                                                  PageS

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Exposure and Emission Evaluations
of Methyl Ethyl Ketoxime (MEKO) in
Alkyd Paints  - Small  environmental
chamber  tests  were   conducted  to
characterize the emissions of a toxic
chemical compound ~ methyl ethyl
ketoxime  (MEKO)  — from three
different alkyd paints. It was found that
MEKO   emissions  occurred  almost
immediately after each alkyd paint was
applied to a pine board.  Due to the fast
emission pattern, more than 90% of the
MEKO emitted was released within 10
hours after painting. The  peak con-
centrations of  MEKO in chamber air
correlated well with the MEKO content
in the paint. Material balance  showed
that good recovery (more  than 68%)
was achieved between the  MEKO
applied with the paint and the  MEKO
emitted.  The  chamber  data were
simulated by  a  first order  decay
emission  model   assuming that  the
MEKO  emissions were mostly gas-
phase mass transfer controlled. The
model  was  used to  predict  indoor
MEKO concentrations during and after
painting in a test house. It was found
that the predicted test  house  MEKO
concentrations during   and after the
painting exceeded a suggested indoor
exposure limit of 0.1 mg/m3for all three
paints.   The  predicted  MEKO
concentrations exceeded even the lower
limit of a suggested sensory irritation
range of 4 to 18 mg/m3 with two of the
three paints tested. The model was also
used to  evaluate  and demonstrate the
effectiveness of risk reduction  options
including  selection of  lower  MEKO
paints and higher ventilation during
painting. Source  Indoor Air,  8, 295-
300, 1998. (EPA Contact: John Chang,
919-541-3747,chang.john@epa.gov)
Indoor Emissions from Conversion
Varnishes - Conversion varnishes are
two-component,   acid-catalyzed
varnishes that are commonly used to
finish cabinets.  They are valued for
their water- and stain-resistance,  as
well as  their appearance. They have
been found, however, to contribute to
indoor   emissions   of  organic
compounds.  For this  project, three
commercially   available  conversion
varnish systems were selected. An EPA
Method 24 analysis was performed to
determine total volatile content, and a
sodium  sulfite titration method was
used to  determine uncombined (free)
formaldehyde  content of the varnish
components. The resin component was
also  analyzed  by  gas  chromato-
graphy/mass spectroscopy  (GC/MS)
(EPA  Method  311 with an MS
detector) to identify individual organic
compounds. Dynamic small chamber
tests were then  performed to identify
and  quantify   emissions   following
application to  coupons  of  typical
kitchen cabinet wood substrates, during
both  curing  and  ageing.  Because
conversion varnishes cure by chemical
reaction, the compounds  emitted during
curing and ageing are not necessarily
the same as those in the formulation.
Results of small chamber tests showed
that the  amount  of  formaldehyde
emitted from these coatings was 2.3 to
8.1  times  the  amount  of  free
formaldehyde applied in the coatings. A
long-term test showed a formaldehyde
emission rate of 0.17 mg/m2/h after
115 days. Source: Journal of the Air &
Waste Manage. Assoc.  48:  924-930,
1998. (EPA Contact:  Elizabeth M.
Howard, 919-541-7915, howard.betsy
@epa.gov)
Inside IAQ, Spring/Summer 1999
                                                                 Page 9

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                                             GLOSSARY

          ACH - Air Change per Hour
          AHU - Air Handling Unit
          CPU - Colony Forming Units
          DMTC - Dynamic Microbial Test
               Chamber
          FDL - Fiberglass Duct Liner
          FGD - Fiberglass Ductboard
          GC/MS - Gas Chromatography/Mass Spectography
          HEPA - High Efficiency Particulate Air
          IAQ - Indoor Air Quality
          IEMB - Indoor Environment Manage-
            ment Branch
MEKO - Methyl Ethyl Ketoxime
NRMRL - National Risk Management
     Research  Laboratory
P2 - Pollution Prevention
RH - Relative Humidity
STKi - Simulation Tool Kit for IAQ
     and Exposure
TVOC - Total Volatile Organic
     Compound
VOC - Volatile Organic Compound
                                                 ERRATA
                           Please note the following typographical  errors in the
                           Spring/Smmer '98 issue of Inside IAQ. Table 4, Page 7, the
                           first  column,   the  entry "Formaldehyde"  should  be
                           "Formaldehyde*" and the entry "Formaldehyde*" should be
                           "Heptachlor"
Inside IAQ, Spring/Summer 1999
                                   Page 10

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                                                Call for Papers

                            Engineering Solutions to Indoor Air Quality Problems

             Engineering Solutions to Indoor Air Quality Problems, an international symposium cosponsored
             by the Air and Waste Management Association and EPA's National Risk Management Research
             Laboratory, will be held July 17-19, 2000,  in Raleigh, NC, at the Sheraton  Capital Center.
             Papers are invited on the following topics:
               Managing the Risk of Indoor Air Pollution
               Indoor Air Source Characterization
                    Methods
               Indoor Air Source Management
               Low Emitting/Low Impact Materials
                  Development (Pollution Prevention)
               Biocontaminant Prevention and Control
               Indoor Air Cleaning Methods
               Asthma and Children's Health in the
                  Indoor Environment
!  Ventilation
!  HVAC Systems as Sources of Indoor
    Air Pollution
!  Air Duct Cleaning
!  Particles and Particle Entry into the
    Indoor Environment
!  Indoor Air Quality Modeling
!  Costs of Managing Indoor Air Quality
!  Evaluation and Verification of IAQ
    Alternatives
              The 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, 2000, to: Michael C. Osborne, U.S. EPA, MD-
              54, Research Triangle Park, NC 27711; Telephone (919)-541 -4113; Fax (919)-541-2157; E-mail:
              osborne.michael@epa.gov. Abstracts should include paper title and author(s) names, address(es),
              and phone, fax number(s), and e-mail address.
Inside IAQ, Spring/Summer 1999
                                    Page 11

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United States
Environmental Protection Agency
National Risk Management Research Laboratory
Indoor Environment Management Branch
MD-54
Research Triangle Park, NC 27711

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