**TECHNIQUES FOR REDUCING EXPOSURES TO VOLATILE ORGANIC COMPOUNDS
ASSOCIATED WITH NEW CONSTRUCTION AND RENOVATION**

A.T. Hodgson^1^ and D.A. Shimer^2^

^1^E.O. Lawrence Berkeley National Laboratory, USA

^2^California Environmental Protection Agency, Air Resources Board, USA

**ABSTRACT**

Chamber experiments were conducted with a combination of latex paints
and new carpet and vinyl flooring assemblies. The first objective was to
characterize the emissions of volatile organic compounds (VOCs) from the
assemblies at simulated residential conditions. The second objective was
to evaluate the effectiveness of techniques that homeowners and building
managers might employ during new construction or renovation to reduce
concentrations of VOCs and exposures to these VOCs. The techniques
included: increased ventilation for three days following installation
(each source); airing out of materials for two days prior to
installation (carpet and vinyl flooring); and mild heating for three
days following installation (combined sources). Short-term ventilation
typically reduced VOC concentrations in room air only during the period
of increased ventilation. Airing out of materials generally reduced the
emissions of VOCs from carpet materials but was ineffective for VOCs
emitted by vinyl flooring. Heating applied after materials were
installed had mixed results.

**INTRODUCTION**

Paints and many materials used to finish the interiors of houses and
other buildings emit volatile organic compounds (VOCs), including toxic
air contaminants (TACs). These emissions result in exposures to
occupants. The California Air Resources Board (ARB) is required to
consider such indoor exposures in assessing risks from TACs to public
health. Thus, it is necessary for the ARB to identify indoor sources of
VOCs and to characterize their emissions. The ARB also provides
information to the public regarding ways to reduce both indoor and
outdoor exposures to TACs.

Numerous techniques for reducing occupant exposures to indoor sources of
VOCs have been proposed. The California Department of Health Services
developed guidelines for reducing exposures to VOCs from construction
materials used in office buildings \[1\]. Tichenor and Sparks employed
an indoor air quality model to predict occupant exposures for different
source scenarios, building parameters and occupant activity patterns
\[2\]. The current study was designed to evaluate selected exposure
reduction techniques in environmental chambers. Emphasis was placed on
practical techniques that homeowners and building managers might use to
reduce occupant exposures to VOCs associated with new construction or
renovation. The study is fully described in a recent report \[3\].

**METHODS**

A variety of interior latex paints, carpets, carpet cushions, and vinyl
floor installation materials widely used by California homeowners were
selected for study. Newly manufactured specimens of 24 materials were
individually screened for emissions of VOCs in small-scale environmental
chambers following standard practice \[4\]. VOCs emitted by the
materials were identified, and the emission rates of selected VOCs were
determined.

In the 2^nd^ phase, 13 large-scale experiments were conducted with
realistic assemblies of new materials that were selected based on the
screening results. The chamber facility with dual, 25-m^3^ compartments
was designed and operated to simulate a residential room environment.
The walls and ceiling of each compartment were painted gypsum board. The
floor was either carpeted or covered with sheet vinyl; and furnishings
(*i.e*., two upholstered chairs and a drapery panel) were installed to
mimic typical "sink" effects. The study materials were installed
following construction industry practice. For experiments with paint, a
fast-drying latex primer sealer (LPS) was first applied to gypsum board
and plywood substrates. This was followed by a flat latex paint (FLP)
applied to 14.9-m^2^ of gypsum board and a semi-gloss latex paint (SGLP)
applied to 1.1-m^2^ of plywood. The carpet and vinyl flooring assemblies
were installed to cover the entire 10.4-m^2^ floor area of a
compartment. For the two experiments with the combined source
assemblies, the paints were applied three days prior to the installation
of the flooring materials, which consisted of two-thirds carpet and
one-third sheet vinyl. Air samples for the analysis of VOCs and
aldehydes were collected from a compartment throughout the first day of
an experiment, daily over the next nine days and finally on day 14
following installation of the materials.

The exposure reduction techniques that were investigated included:
additional ventilation for three days following installation (each
source assembly); additional air mixing combined with additional
ventilation (paint combination); airing out of materials for two days
prior to installation (carpet and vinyl flooring assemblies); and room
heating to 33o C for three days after painting and installing the
flooring materials (combined source assemblies). The results for the
treatment experiments were compared to the results for base-case
experiments conducted at standardized conditions for ventilation, air
mixing and temperature. For the base-case experiments, the ventilation
rate was held at 2 h^-1^ during material installation and for the next
two hours. Then it was reduced to 0.5 h^-1^ and held at that condition.
For experiments with additional ventilation, the rate during material
installation and the next two hours was 5 h^-1^. The rate was then
reduced to 2 h^-1^ and held at that condition until 72-h elapsed time
when it was further reduced to 0.5 h^-1^.

Air samples for VOCs were collected on Tenax-TA sorbent tubes. These
were analyzed for VOCs by thermal desorption GC/MS using a modification
of U.S. EPA Method TO-1. Emission rates of the target VOCs were
calculated by a steady-state mass-balance model \[4\].

Predicted exposure was calculated for two different time periods or
scenarios. The 1^st^ scenario was for an occupant who was present during
the first 48 hours following installation. The 2^nd^ scenario was for a
full-time occupant who vacated the residence during the first 48 hours
and then returned. Occupancy for 20 hours per day (*i.e*., an occupancy
factor of 0.83) was assumed for both scenarios. The cumulative exposure
for a target VOC was calculated as the product of the concentration
profile, the exposure time in hours, and the occupancy factor.

**RESULTS**

The screening measurements generated a large amount of qualitative and
quantitative data. The VOC emissions from conventional latex paints
principally consisted of a solvent component (ethylene glycol and/or
propylene glycol) and the Texanol coalescing aid. The 96-h emission
rates of SigmaVOC (*i.e*., the sum of the rates for individual VOCs)
from eight conventional and two non-VOC latex paints are compared in
Figure 1. The LPSs and FLPs were applied to gypsum board. The SGLPs were
applied to plywood. The two non-VOC paints, FLP4 and SGLP4, had
substantially lower emission rates than did the conventional paints.
These emissions consisted of small amounts of oxidized compounds. Paints
LPS2, FLP3 and SGLP3 were selected for use in the large-scale
experiments.

![](media/image1.wmf)Approximately 3.6 kg of the combined paints was
applied in each large-scale experiment. Ethylene glycol (EG) and
Texanol were the dominant emitted compounds (Table 1). Other compounds
included acetaldehyde, propylene glycol and di(ethylene glycol)butyl
ether. The maximum concentrations of the target compounds occurred
within the first few hours after paint application. The experiments were
compared over elapsed time periods of only 240 h since one experiment
was terminated early. There were \~98% reductions in the concentrations
of EG over this period. For all cases, 60% of the total cumulative
exposures to this compound occurred within the first 48 h. The
concentrations of Texanol decreased by a factor of \~3.5 over the
course of the experiments. The use of additional initial ventilation
resulted in small decreases in exposures to EG and Texanol over both
the 0- to 48- and the 48- to 240-h time periods (Table 1). The small
effect in the initial period was due to increased emission rates in
response to additional ventilation. Additional air mixing created with
two oscillating fans pointed at the painted surfaces in combination with
additional ventilation resulted in somewhat greater exposure reductions
relative to the base-case condition.

The carpet assembly selected for the large-scale experiments consisted
of a carpet with olefin face fibers and a bonded urethane carpet
cushion. This assembly had substantially lower emissions of VOCs than
the paint and vinyl flooring. (Note that the concentrations and
exposures for the carpet and vinyl flooring assemblies are presented in
ppb and ppb-h units.) The carpet emitted styrene, 4-ethenycyclohexene,
4-phenylcyclohexene (4-PCH), isomers of di(propylene glycol)methyl ether
(DPGME) and N,N-dimethylacetamide. The cushion emitted butylated
hydroxytoluene (BHT), 2,2\'-azobisisobutryonitrile and a complex mixture
of unsaturated hydrocarbons. Data for 4-PCH, DPGME and BHT are shown in
Table 2. There were five-fold or more reductions in the concentrations
of DPGME over the course of the experiments. The concentrations of 4-PCH
only decreased by a factor of two or less while the concentrations of
BHT increased with time. The concentrations of the individual VOCs at
the ends of the experiments were \~1 ppb or less. The use of additional
initial ventilation resulted in decreases in the exposures to most VOCs
over 0-48 h (Table 2). However, the 48- to 336-h exposures to most VOCs
were affected by less than 10% due to use of higher initial ventilation.
Airing out of the carpet and cushion in a well-ventilated space for two
days prior to installation substantially reduced the exposures to all
VOCs in both time periods relative to the base-case experiment.

The vinyl flooring assembly selected for the large scale experiments
consisted of residential \"no-wax\" sheet vinyl, low-VOC full-spread
adhesive, liquid seam sealer, rubber cove base and cove base adhesive.
Use of the seam sealer produced high (ppm) initial concentrations of
tetrahydrofuran (THF) and cyclohexanone. The full-spread adhesive
emitted toluene. The dominant compounds emitted by the sheet vinyl were
n-tridecane (n-C13), other alkane hydrocarbons, 1,2,4-trimethylbenzene,
benzyl alcohol, phenol and TXIB plasticizer. The cove base emitted
benzothiazole. Data for n-C13, toluene, THF and phenol are shown in
Table 3. There were rapid 100-fold or more reductions in the THF and
cyclohexanone concentrations over the course of the experiments. There
were also substantial rapid reductions in the toluene concentrations in
all experiments. The use of additional initial ventilation clearly
reduced the exposures to most VOCs over 0-48 h (Table 3). However, the
apparent emission rates of benzyl alcohol, phenol, TXIB and
benzothiazole, all relatively low volatility compounds, increased in
response to additional ventilation. Thus, the exposure to TXIB was only
reduced by 22% and the exposures to the other three compounds were
affected by less than 10% during the initial period. The 48- to 336-h
exposures to most VOCs were affected by less than 10% as the result of
additional ventilation during the first 72 h. The most impacted
compounds were toluene, THF and phenol with 16-30% reductions. Airing
out of the sheet vinyl and cove base reduced the 0- to 48-h exposures to
most VOCs by 25% or less. The most impacted compounds were phenol and
benzothiazole with \~40% reductions. This treatment was less effective
for reducing exposures over the longer period.

![](media/image2.wmf)Heating the compartment to 33^o^ C for three days
following the installation of combined assemblies resulted in increases
in the chamber concentrations of most VOCs during the heating period. At
the onset of heating, there were rapid, typically three-fold
concentration increases, which declined over the 72-h heating period.
When the heat was turned off, the concentrations typically returned to
values similar to the base-case values. Texanol was a notable
exception. Subsequent to heating, the concentrations of Texanol were
lower relative to the reference case. The cumulative exposures to
selected VOCs in the heating and base-case experiments are compared in
Figure 2. Occupancy was assumed to begin after the compartment
temperature returned to normal. There was an increase in the exposure
for THF and a more than two-fold decrease in the exposure for Texanol
due to heating.

**DISCUSSION AND CONCLUSIONS**

A moderate increase in building ventilation during and for a short
period following the installation of an indoor VOC source is probably
the most accessible and practical exposure reduction technique for
consumers. VOC concentrations were reduced during the period of
additional ventilation; however, the reductions were frequently not
directly proportional to the magnitude of the ventilation increase. VOC
concentrations following the termination of additional ventilation often
quickly returned to base-case values. An alternative exposure reduction
technique is to select materials for new construction and renovation
that have low emissions of VOCs. However, the informed selection of
low-emitting materials is frequently a complex and difficult task.

The results of the investigation have been generalized to formulate the
following practices that homeowners and building managers can employ to
reduce VOC concentrations and decrease cumulative exposures to VOCs for
occupants of houses and other buildings.

1\) Materials that emit lower amounts of toxic or odorous VOCs should be
selected whenever possible. Lower emitting materials should reduce
occupant exposures and decrease the need for subsequent control
strategies. The substitution of non-VOC latex paints for conventional
latex paints appears to be one viable choice for reducing exposures.

2\) The most effective way to reduce occupant exposures to the dominant
VOCs emitted by conventional latex paints is to delay occupancy for
several days following painting. This strategy may also be effective for
reducing exposures due to sheet vinyl installations.

3\) Although carpets and carpet cushions are relatively low sources of
VOCs, exposures to VOCs emitted by these materials can be reduced by
airing them out in a well-ventilated, clean, dry environment for several
days prior to their installation.

4\) High mechanically induced ventilation rates should be used during
the application or installation of high emitting materials such as
paints and vinyl seam sealers to protect the installers and any
occupants that are present.

5\) Additional ventilation should be maintained for periods longer than
three days to more effectively lower occupant exposures. The ventilation
rate should be maximized since, in many cases, the beneficial effects of
ventilation, are not in direct proportion to the increase in the
ventilation rate.

**ACKNOWLEDGEMENT AND DISCLAIMER**

Sponsored by the California Environmental Protection Agency, Air
Resources Board under Contract No. 95-302 and by the U.S. Depart. Of
Energy, Assist. Secretary for Energy Efficiency and Renewable Energy,
Office of Building Technology, State and Community Programs under
Contract No. DE-AC03-76SF00098. The statements and conclusions herein
are those of the authors and not necessarily those of the sponsoring
agencies. The mention of commercial products or their use in connection
with material reported herein is not to be construed as actual or
implied endorsement of such products.

**REFERENCES**

1\. Alevantis, L.E. 1996. Reducing occupant exposure to volatile organic
compounds (VOCs) from office building construction materials:
Non-binding guidelines. California Department of Health Services Report
released July, 1996, 46 p.

2\. Tichenor, B.A. and L.E. Sparks. 1996. Managing exposure to indoor
air pollutants in residential and office environments. *Indoor Air*
**6**: 259-270.

3\. Hodgson, A.T. 1999. Common Indoor Sources of Volatile Organic
Compounds: Emission Rates and Techniques for Reducing Consumer
Exposures. Final Report to California Environmental Protection Agency,
Air Resources Board, Contract No. 95-302.

4\. ASTM. 1997. *ASTM Standard D 5116-97, Standard Guide for Small-Scale
Environmental Chamber Determinations of Organic Emissions from Indoor
Materials/Products*. American Society for Testing and Materials,
Philadelphia, PA.

Table 1. Effects of additional initial ventilation and air mixing on
concentrations and\
exposures to selected VOCs emitted by latex paints.

  -- ------------ ---------- ---------- ---------- --------- ---------- ----------
     Compound     Added\     Air Mixing Max.       Conc.\    Exposure   Exposure
                  Vent.\     (Yes/No)   Conc.\     @ 240 h   0-48 h     48-240 h
                  (Yes/No)              1-48 h\    (ppm)     (ppm-h)    (ppm-h)
                                        (ppm)                           

     EG           No         No         6.7        0.148     72         37

                  Yes        No         6.5        0.129     59         38

                  Yes        Yes        4.0        0.118     45         28

     Texanol     No         No         0.48       0.138     14.1       36

                  Yes        No         0.63       0.179     12.4       31

                  Yes        Yes        0.49       0.164     10.8       26
  -- ------------ ---------- ---------- ---------- --------- ---------- ----------

Table 2. Effects of additional initial ventilation and airing out of
materials on concentrations\
and exposures to selected VOCs emitted by carpet assembly.

  -- ------------ ---------- ---------- ---------- --------- ---------- ----------
     Compound     Added\     Airing Out Max.       Conc.\    Exposure   Exposure
                  Vent.\     (Yes/No)   Conc.\     @ 336 h   0-48 h     48-336 h
                  (Yes/No)              1-48 h\    (ppb)     (ppb-h)    (ppb-h)
                                        (ppb)                           

     4-PCH        No         No         1.9        0.9       70         320

                  Yes        No         1.5        1.1       53         300

                  No         Yes        1.4        0.8       46         260

     DPGME        No         No         4.2        0.5       111        198

                  Yes        No         3.2        0.6       66         187

                  No         Yes        0.9        \<0.5     32         \<109

     BHT          No         No         0.7        0.9       14         152

                  Yes        No         0.8        1.2       17         220

                  No         Yes        0.4        0.8       10         122
  -- ------------ ---------- ---------- ---------- --------- ---------- ----------

Table 3. Effects of additional initial ventilation and airing out of
materials on concentrations\
and exposures to selected VOCs emitted by vinyl flooring assembly.

  -- ------------- ---------- ---------- ---------- --------- ---------- ----------
     Compound      Added\     Airing Out Max.       Conc.\    Exposure   Exposure
                   Vent.\     (Yes/No)   Conc.\     @ 336 h   0-48 h     48-336 h
                   (Yes/No)              1-48 h\    (ppb)     (ppb-h)    (ppb-h)
                                         (ppb)                           

     n-Tridecane   No         No         27         6.1       420        1,720

                   Yes        No         11.3       6.8       220        1,620

                   No         Yes        23         7.6       370        1,820

     Toluene       No         No         60         8.2       870        2,800

                   Yes        No         11.2       8.2       196        2,100

                   No         Yes        44         8.8       580        2,200

     THF           No         No         2,600      2.7       7,300      2,000

                   Yes        No         330        3.4       1,400      1,400

                   No         Yes        2,200      5.8       8,900      2,400

     Phenol        No         No         32         16.9      930        4,700

                   Yes        No         21         15.9      730        3,900

                   No         Yes        18.7       15.9      510        4,000
  -- ------------- ---------- ---------- ---------- --------- ---------- ----------