Inside IAQ, Spring/Summer 1997 Page 1

United States Environmental Office of Research and Development

Protection Agency Research Triangle Park, NC 27711

EPA/600/N-97/003 Spring/Summer 1997

 EPA Inside IAQ 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

Att. 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 2

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 Cin (the average inlet concentration) as:

Cs = Cin (1 - e-Nt) (1)

where t = time, h, and N=air exchange rate, h-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 Cin.

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

Test

Material

Cin

(mg/m3)

Dosing

Period (h)

Cout

(mg/m3)

Dosage

(mg/m2)

Mads

(mg/m2)

Mads/Cin

(m)

Propylene Glycol Gypsum 5.32 168 1.53 893 488 91.7

Ethylene Glycol Gypsum 7.12 168 3.69 1196 628 88.2

BEE Gypsum 3.43 168 1.83 576 317 92.4

Texanol Gypsum 5.43 168 2.68 921 483 89.0

Propylene Glycol Carpet 5.38 168 2.11 903 627 116.5

Ethylene Glycol Carpet 5.68 168 2.56 954 662 116.5

BEE Carpet 3.80 169 1.72 642 264 69.5

Texanol Carpet 6.21 169 4.60 1049 232 37.4

Cin = 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

Test

Material

Cend

(mg/m3)

Purging

Period (h)

Mads

(mg/m3)

Mdes

(mg/m2)

Mdes/Mads

(%)

Propylene Glycol Gypsum 0.09 356 488 55.7 11

Ethylene Glycol Gypsum 0.11 356 628 76.8 12

BEE Gypsum 0.03 387 317 43.4 14

Texanol Gypsum 0.08 387 483 85.5 18

Propylene Glycol Carpet 0.45 291 627 204 33

Ethylene Glycol Carpet 0.52 291 662 246 37

BEE Carpet 0.13 340 264 78 30

Texanol Carpet 0.16 340 232 163 70

Cend = outlet concentration at the end of purging period

Mdes = mass desorbed from sink during purging period
Inside IAQ, Spring/Summer 1997 Page 3

0 40 80 120 160

Elapsed Time (h)

0

2

4

6

8

10

Concentration (mg/m3)

Average Inlet Conc. (Cin)

Outlet Conc. (Cs)

No-Sink Model

Surface Adsorption Model

0 100 200 300 400

Elapsed Time (h)

0.1

1

10

Concentration (mg/m3)

Outlet Conc. (Cd)

Surface Adsorption Model

No-Sink Model

0 40 80 120 160

Elapsed Time (h)

0

2

4

6

8

Concentration (mg/m3)

Average Inlet Conc. (Cin)

Outlet Conc. (Cs)

No-Sink Model

Surface Adsorption Model

0 100 200 300 400

Elapsed Time (h)

0.1

1

10

Concentration (mg/m3)

Outlet Conc. (Cd)

Surface Adsorption Model

No-Sink Model

Figure 1. Adsorption of Ethylene Glycol from

Gypsum Board in Dosing Phase

Figure 2. Desorption of Ethylene Glycol from

Gypsum Board in Purging Phase

Figure 3. Adsorption of Texanol from

Gypsum Board in Dosing Phase

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 4

Mads = NV(Ain - Aout)/S (4) 

where, Ain = area under Cin 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/Cin 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

Ke 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 Ke were in the

range of 0.90 to 6.25 m. It is apparent that the values of

Mads/Cin listed in Table 1 and the corresponding Ke values are

considerably greater than those Ke 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 = Cin {1 - [(N - r1)exp(-r2t) - (N - r2)exp(-r1t)]/ (r2- r1)} (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(-r1t)-[LkdMdo-

(N+Lka-r1)Cdo]exp(-r2t)}/(r2-r1) (6)

where, ka = 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 -1, V = volume at

chamber, m3, and r1 and r2 = two parameters estimated by

r1, 2 = {(N + Aka/V + kd) ± [(N + Aka/V + kd)

2

- 4Nkd]

0.5 }/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 5

THE EFFECTIVENESS OF ANTIMICROBIAL

SURFACE TREATMENTS

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 over time. 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 inplace 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 Cary,

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 6

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 a non-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 #

House

Age

(yrs)

House

Size

(m2)

# of

Floors

Duct

Age

(yrs)

AHU

Age

(yrs)

Duct

Material

TH 20 121.2 1 20 20 a

2 22 141.2 1 22 22 b

3 18 134.7 1 18 0.5 c

4 10 183.9 2 10 10 d

5 9 185.8 2 9 9 d

6 28 181.6 1.5 NA NA b

7 25 92.9 1.5 25 NA c

8 26 185.8 2 26 26 b

9 35 139.3 2 35 NA 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. PreADC 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 Fg/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 7

0 

10 

20 

30 

40 

Deposition (mg/m2)

TH 2 3 4 5 6 7 8 9

House Number

Pre-clean

Post-clean

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 measurements 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

HAC systems contaminated with dirt and dust are potential

IAQ emission sources. Research shows that HAC 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 8

EMISSIONS FROM ACID-CATALYZED

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

μg/m3 (12 ppb) if the source area is 5 m2, and 67 μg/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 Page 9

0 

100 

200 

300 

400 

Conc. (ug/m3)

0 0.2 0.4 0.6 0.8 1 

Air Exchange Rate (1/hr)

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 ANALYSIS

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 150oC which is within the range of

typical fusing temperatures in dry-process photocopy machines (100-160oC). Four of the major VOCs

identified in earlier large chamber tests – ethylbenzene, m,pxylene, 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 loweremitting toners. (EPA Contact: Kelly Leovic, 919-541-7717,

e-mail:kleovic@engineer. aeerl.epa.gov)

Table 4. Toner Headspace Concentrations (ng/mL)

Chemical Emitted Toner A Toner B Toner C

Ethylbenzene 1100 950 220

m,p-Xylene 1100 930 470

Styrene 290 260 130

o-Xylene 740 660 290
Inside IAQ, Spring/Summer 1997 Page 10

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 loweremitting 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 dryprocess 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 flowthrough 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:

C 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. 

C 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 EC 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 31oC represents a mass of water

equivalent to 50% RH at 23oC.)

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 dryprocess photocopy machines evaluated.

C 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.

C Power Requirements: The type of outlet required varies

among copiers. Installation of new outlets, changing

outlets, or multiple outlets may be required.

C 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 dryprocess 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 11

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 μg/h for Copier 1 and <50 μg/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 μm 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 test method provided

acceptable performance for characterizing emissions from dryprocess 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

μg/hour), m,p-xylene (29,000 μg/hour), o-xylene (17,000

μg/hour), 2-ethyl-1-hexanol (14,000 μg/hour), and styrene

(12,000 μg/hour). To put these results in perspective, chamber

air concentrations of styrene were about 100 μg/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 (μg/h @ copier)

Chemical Copier

1

Copier

2

Copier

3

Copier

4 

Ethylbenzene 28,000 360 2,400 <50

m,p-Xylene 29,000 510 6,100 100

Styrene 9,900 3,000 12,000 300

o-Xylene 17,000 850 4,500 <50

Propylbenzene 790 460 2,100 <50

2-Ethyl-1-hexanol 230 5,600 14,000 130

n-Nonanal 1,100 3,900 3,600 2,000

n-Undecane 2,000 62 70 103

Formaldehyde <500 <500 2,600 2,200

Acetaldehyde 710 <500 960 1,200

Acetone 2,000 >100 >500 2,800

Benzaldehyde 1,800 3,800 2,600 <100

Ozone 3,000 1,300 4,700 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

IAQ-Indoor Air Quality

IEMB-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

PIV-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 12

IEMB PAPERS AT ENGINEERING 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 IEMB-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-IEMB

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 Air-The capital,

operating, and maintenance costs were

compared for VOC air cleaning by induct 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 13

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 (PIV) which has nonintrusive, 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 of Fungally 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 shortterm 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-In 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 Air-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 14

Indoor Air Quality Large Building

Characterization Project PlanningThree 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 m3stainless 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.”) A pilot 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 15

Reducing Solvent and Propellant

Emissions from Consumer ProductsThe 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 WindowsRISK, 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 IEMB’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)
Reducing Indoor Air Emissions from

Dry-Process Photocopy MachinesEmissions 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 manufacturing 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

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