United States Environmental Office of Research and Development

Protection Agency Research Triangle Park, NC 27711

EPA/600/N-96-002 Spring/Summer 1996

 EPA Inside IAQ EPA's Indoor Air Quality Research Update

Engineering Solutions to

Indoor Air Quality Problems

Symposium

July 21-23, 1997

Research Triangle Park, NC

(See Page 12 for Call for Papers)

In This Issue Page

IEMB’s Large Chamber .............. 1

Effects of HVAC Fan Cycling on the

 Performance of Particulate Air Filters . . 2

Reducing Indoor Air Emissions from

 Engineered Wood Products .......... 5

Cost-Effectiveness of Alternative

 IAQ Control Techniques ............ 6

Quality Assurance for EPA’s IAQ

 Research ....................... 7

Emissions of Carbonyl Compounds

 from Latex Paint ................. 8

Glossary of Acronyms .............. 8

Summaries of Recent Publications ...... 9

Contacts in IEMB ................. 11

Inside IAQ is distributed twice a year by the

Office of Research and Development’s

National Risk Management Research

Laboratory’s (NRMRL) Air Pollution

Prevention and Control Division (APPCD).

Indoor air quality (IAQ) research conducted by

APPCD’s Indoor Environment Management

Branch (IEMB) is highlighted. If you would

like to be added to or removed from the

mailing list, please mail, fax, or e-mail your

name and address to:

 Inside IAQ, Attn. Kelly Leovic 

 U.S. EPA (MD-54)

 Research Triangle Park, NC 27711

 Fax: 919-541-2157

 E-mail: kleovic@engineer.aeerl.epa.gov

IEMB’s LARGE CHAMBER

IEMB has designed and installed a state-of-the-art large chamber in their

Research Triangle Park Facility. The room-sized (30-m3) stainless steel test

chamber and sophisticated analytical instrumentation will permit

characterization of emissions from products and processes that cannot

readily be studied using small chambers. The new facility will enable

researchers to study, under highly controlled environmental conditions,

indoor pollution episodes such as interior painting and use of other

consumer products that impact IAQ. These types of processes often result

in high initial personal exposures and also load other surfaces (i.e., sinks)

such as carpets, wall coverings, and ceiling tiles with pollutants that may be

re-emitted to the indoor air over a long period of time.

The test chamber’s versatile air distribution system (Figure 1) permits

researchers to simulate home or office air distribution patterns and test

in-room and in-duct air cleaning devices. System design permits single

pass, partial, or complete recirculation of highly filtered air that is

supplied to the chamber through glass ducting. Chamber temperature, air

exchange rate, relative humidity (RH), and pressure are automatically

set and controlled by a computer.

Many of the basic elements of the large chamber design have been

incorporated into large chambers constructed in Canada and Australia.

Initial experiments conducted in the large chamber will include tests to

evaluate the performance of EPA’s chamber and determine

comparability with these other chambers. Future collaborative research

will be directed toward development and validation of test methods and

indoor air models as well as investigation of important sources and

control strategies.

Currently, IEMB is conducting tests to fine tune the chamber. Tests that

are underway are designed to evaluate critical factors that may influence

experiments. These tests are designed to evaluate the 1) ability of the

chamber control system to maintain a wide variety of temperature and

RH set points; 2) air velocities within the chamber at different flow

conditions; 3) mixing of pollutants at low, elevated, and normal

temperatures and at high and low air flow rates; and 4) adsorption of

volatile organic compounds (VOCs) by chamber walls, air duct walls,

and components of the air-conditioning system.

(Continued on Page 2)
Inside IAQ, Spring/Summer 1996 Page 2

MAIN

CONDITIONING ADSORBER

EXHAUST TO OUTDOORS

MAX. 700 CFM

PRECONDITIONINGDEHUMIDIFIER

AIR

CLEANER

MODULE

CHAMBER

MAX. 500 CFM

MIN. 5 CFM

DAMPER

FAN

RECIRCULATION RECIRCULATION

FAN

1

FAN

2

FAN

3

INLET

AIR

1 CUBIC FOOT/ MINUTE (CFM) =

0.47 LITER/ SECOND

Figure 1. Schematic of IEMB’s Large Environmental

 Chamber

Results indicate that the automated control system can

maintain temperatures over a range of 15 to 30EC with RHs

ranging from 30 to 70% when chamber air is recirculated

through the air-conditioning system. As expected, when the

chamber is operated in single pass, low flow mode, the

temperature inside the chamber varies with the air

temperature of the room housing the chamber. Mixing tests

indicate that pollutants introduced into the chamber mix

rapidly and do not appear to “short circuit” between the

inlets near the floor and the outlet in the ceiling. Chamber

wall loss tests have demonstrated insignificant to slight

adsorption of several typical indoor air contaminants when

the chamber is operated in single pass mode (no

recirculation of air through the chamber air-conditioning

system). These results indicate that wall effects in the large

chamber are very small compared to wall effects that have

been observed in small test chambers. Adsorption of low

volatility and polar compounds has been observed when

chamber air is recirculated through the air-conditioning

system. These effects are manageable and are not expected

to interfere with use of the chamber to characterize sources

and develop source management methods that result in

reduced exposure to indoor air pollutants. Future issues of

Inside IAQ will provide updates on tests conducted in the

chamber. (EPA Contacts: Mark Mason, 919-541-4835,

mmason@engineer. aeerl.epa.gov and Betsy Howard, 919-

541-7915, bhoward@ engineer.aeerl.epa.gov)

EFFECTS OF HVAC FAN CYCLING ON THE

PERFORMANCE OF PARTICULATE AIR FILTERS

Heating, ventilating, and air-conditioning (HVAC) system

components have been identified as potential emission

sources that may affect IAQ under some conditions (HVAC

Systems as Emission Sources Affecting Indoor Air Quality:

A Critical Review, EPA-600/R-95-014; NTIS PB95-

178596, February 1995). Emissions include dust, dirt, and

other airborne particles entrained from outdoor air (OA)

and from air recirculated from the occupied spaces. These

contaminants accumulate on HVAC surfaces including the

filtration systems. Dirty or loaded filters have been

associated with total particle and bioaerosol shedding as the

system fan cycles on and off. 

Filters are installed in HVAC systems by design engineers

for two primary reasons: 1) protection of system

components (fans, motors, control devices, etc.) from the

degrading effects of dust and dirt, and 2) reduction of

occupant exposure to airborne particles and bioaerosols. It

has been suggested that dirty or loaded filters may be

associated with total particle and bioaerosol shedding as the

HVAC system fan cycles on and off.

IEMB and the University of Minnesota performed research

to determine the shedding contribution from loaded filters

(see Effects of Fan Cycling on the Performance of

Particulate Air Filters Used for IAQ Control on page 9).

Fiberglass and synthetic organic media bag filters were

tested using two laboratory test duct setups. Each test duct

was 2 by 2 ft (0.6 by 0.6 m). The blower fan, which was

cycled on and off, was configured as a draw-through system

that challenged the filters with 100% OA. Total airborne

particle counts were made with an optical particle counter,

and viable bioaerosol counts were obtained with a slit

impactor with a rotating plate. Filter surface microorganism

samples were obtained with growth plates. The two filters

tested were a fiberglass bag filter with a rated dust spot

efficiency of 85% and a synthetic organic media bag filter

with a rated dust spot efficiency of 65%. Both filters have

eight pleated pockets.

The filters were loaded with outdoor aerosols with the fan

running continuously except for the time when the fan

cycling data were obtained. Initial tests on clean filters

were inconclusive so the tests reported here were made after

the filters had been loaded for approximately 1 year.

(Continued on Page 3)
Inside IAQ, Spring/Summer 1996 Page 3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

0

100,000

200,000

300,000

400,000

500,000

600,000

fan turned off fan turned on again

Readings

Particles/ ft3 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

Readings

fan turned off fan turned on again

Particles/ ft3 

0-5

5-10

10-1515-2020-2525-3030-3535-4040-4545-5050-5555-6060-6565-7070-7575-8080-8585-9090-95

95-100

100-105

105-110

110-115

115-120

0

5

10

15

20

25

30

Time span (seconds)

CFUs/ft3

duct access door

closed

Fan turned off Fan turned on 

again

0-5

5-10

10-1515-2020-2525-3030-3535-4040-4545-5050-5555-6060-6565-7070-7575-8080-8585-9090-95

95-100

100-105

105-110

110-115

115-120

0

2

4

6

8

10

12

Time span (seconds)

CFUs/ft3

Fan turned off

duct access door

closed

Fan turned on 

again

Figures 2 and 3 illustrate typical total particle concentrations measured upstream and downstream from the

fiberglass filter when the fan was cycled off and on.

Figures 4 and 5 show the bioaerosol collected versus time

by the slit impactor downstream from the fiberglass filter

when the fan was cycled. Results from the synthetic organic filter are similar. Table 1 shows the results of a surface

sampling test using Inhibitory Mold Agar (IMA) growth

media.

Figure 2 shows that the particle concentration in the upstream

duct (i.e.,OA) does not change during the fan cycling. In some

of the runs, the concentration dropped when the fan was turned

off. However, the total concentration in these runs was much

higher than the values shown in Figure 2 and settling losses

were significantly higher.

The downstream concentration of particles in Figure 3

shows a trend found in most of the tests. When the fan is

turned off, the air velocity through the filter gradually

decreases as the fan wheel slows to a stop. Media filters

become more efficient when the velocity through them is

reduced as the particles have longer residence time to

diffuse to the filter media. Therefore, the particle

concentration downstream of the filter decreases shortly

after the fan is turned off. The fan discharges air through a

set of open dampers and a short duct section directly

outdoors. With the fan off, outdoor contaminants can

diffuse into the discharge duct. This causes the

concentrations on the downstream side of the filter to

increase. Note that the downstream concentration at

readings 10 and 11 on Figure 3 are still much lower than

the upstream levels shown in Figure 2. Long term tests

with the fan off indicated that the downstream

concentrations never reach upstream concentrations. This

is caused by settling and diffusion to surfaces between the

filter and outdoors. When the fan is restarted, the downstream particle concentrations rapidly return to the level

before the fan was stopped. 

Results from one of the viable bioaerosol tests are shown in

Figures 4 and 5. Concentrations of colony forming units

(CFUs) are high immediately after the impactor is started

and the access door closed. This is caused by room air

entering the ductwork downstream of the filter because the

duct is at a negative pressure with respect to the room.

Particles may also be dislodged from the duct surfaces and

perhaps the filter when the door is closed. Shortly after the

door is closed, the downstream bioaerosol counts decrease

to nearly zero. The counts remain low during the fan

cycling. There are a few random counts but no repeatable

pattern of bioaerosol concentrations was observed.

(Continued on Page 4)

Figure 2. Total particle concentration versus time upstream

from the fiberglass filter (31 seconds between

successive readings) (1 ft3 = 28 L)

Figure 3. Total particle concentration versus time downstream from the fiberglass filter (31 seconds

between successive readings) (1 ft3 = 28 L)

Figure 4. Total bioaerosol concentration versus time downstream from the fiberglass filter (IMA media)

 (1 ft3 = 28 L)

Figure 5. Total bioaerosol concentration versus time downstream from the fiberglass filter (Standards

Method Agar media) (1 ft3 = 28 L)
Inside IAQ, Spring/Summer 1996 Page 4

Table 1 shows the results of one of the surface sampling

tests for both the fiberglass and synthetic organic filters

using IMA media. The microbial counts upstream of the

filters are high on the filter surface and on the bottom

surface of the duct. Counts are lower on the side walls of

the duct. Downstream, the counts are very low almost

everywhere indicating good bioaerosol removal by both bag

filters.

In conclusion, no statistically significant particle shedding

from the bag filters was observed by either the optical

particle counter or the viable bioaerosol slit impactor when

the fan was cycled. These results are different from

previous research; however, the filter media and types may

have been different. When the fan was turned off, total

particle concentrations downstream of the filter decreased

initially followed by a marked increase. This can be

explained by an increase in filter capture efficiency at low

air velocity and by diffusion of outdoor particles into the

discharge ductwork when the fan was off. Surface samples

for viable fungi and bacteria generally indicated high levels

on the upstream sides of the filters and on the upstream duct

surfaces but very low counts downstream. (EPA Contact:

Russ Kulp, 919-541-7980, rkulp@engineer. aeerl.epa.gov)

Table 1. Surface Sampling Test Results (IMA Media)

Filter Type Location Sample Results *

Fiberglass Upstream Bag 5, upper end overgrowth

Fiberglass Upstream Bag 5, lower end overgrowth

Fiberglass Upstream Side duct wall moderate growth

Fiberglass Upstream Side duct wall (door) moderate growth

Fiberglass Upstream Bottom duct wall overgrowth

Fiberglass Downstream Bag 5, upper end no growth

Fiberglass Downstream Bag 5, lower end no growth

Fiberglass Downstream Side duct wall no growth

Fiberglass Downstream Side duct wall (door) low growth

Fiberglass Downstream Bottom duct wall low growth

Synthetic Organic Upstream Bag 5, upper end overgrowth

Synthetic Organic Upstream Bag 5, lower end overgrowth

Synthetic Organic Upstream Side duct wall moderate growth

Synthetic Organic Upstream Side duct wall (door) moderate growth

Synthetic Organic Upstream Bottom duct wall overgrowth

Synthetic Organic Downstream Bag 5, upper end low growth

Synthetic Organic Downstream Bag 5, lower end no growth

Synthetic Organic Downstream Side duct wall no growth

Synthetic Organic Downstream Side duct wall (door) no growth

Synthetic Organic Downstream Bottom duct wall moderate growth

 * low growth = 1-10 CFUs

 moderate growth = 11-30 CFUs

overgrowth = colonies merge together
Inside IAQ, Spring/Summer 1996 Page 5

PBVST HBVSST PBVY PBM

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

Other VOC

Alcohols

3038

2887

2631

7083

7787

1004

Emission rates (μg/m2/hr)

PBVST = Veneered Particleboard with Sealer and Topcoat

HBVSST = Veneered Hardboard with Stain, Sealer, and Topcoat

PBVY = Particleboard with Vinyl

PBM = Particleboard with Melamine

294

0 0

PBVST = Veneered Particleboard with Sealer and Topcoat

HBVSST = Veneered Hardboard with Stain, Sealer, and Topcoat

PBVY = Particleboard with Vinyl

PBM = Particleboard with Melamine

PBVST HBVSST PBVY PBM

0

200

400

600

800

1,000

1,200

1,400

Acetone Formaldehyde Hexanal Other

Emission rates (μg/m2/hr)

53

275

217

31 days 71

31 days

24 hours

24 hours

77

318

184

528

11

174

77

130

283

833

PB V PBV PBVS PVBST 0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

Alcohols Aldehydes/Ketones Other VOC

1109

Emission rates (μg/m2/hr)

PB = Particleboard

V = Veneer

PBV = Veneered Particleboard

PBVS = Veneered Particleboard with Sealer

PVBST = Veneered Particleboard with Sealer and Topcoat

400 649

707

1131

757

93

101

19

370

90

38

22

REDUCING INDOOR AIR EMISSIONS FROM

ENGINEERED WOOD PRODUCTS

Research over the past two decades has shown that

engineered wood products can be emission sources for

many organic compounds. Emissions can arise from the

engineered wood (both the wood and resin); finishing

materials applied to the engineered wood for decorative

purposes such as finished wood veneer, ink prints, and

paper overlays; and glues used to fasten pieces of finished

engineered wood together. Research Triangle Institute is

working cooperatively with IEMB to characterize indoor

emissions from engineered wood products and to identify

and evaluate pollution prevention approaches for their

manufacture that may reduce indoor emissions. 

As part of the project, emissions have been characterized

from four types of finished engineered wood: 1)

particleboard finished with melamine; 2) particleboard

finished with vinyl; 3) finished veneered hardboard; and 4)

finished veneered particleboard. The test samples were

obtained directly from the manufacturing line at the

finishing plant. The finished samples were cut into small

coupons (3 by 3 in., 7.44 by 7.44 cm) and placed in 1-gal.

(3.785 L) steel containers with one coupon per container.

The containers were transported to Research Triangle

Institute within 24 hours of collection.

Figure 6 shows 24-hour emission rates of total VOCs from

each of the substrates. The finished veneered particleboard

and hardboard have substantially higher emission rates of

total VOCs compared to the vinyl and melamine

particleboard. As seen in Figure 7, 31-day emission rates of

formaldehyde from the finished substrates were also higher

than 24 hr emissions rates of formaldehyde from the

melamine and vinyl particleboard (217 and 275 μg/m2/hr

compared to 53 and 71 μg/m2/hr).

Additional testing indicated that surface finishes applied to

the veneered particleboard and hardboard were a significant

source of emissions from the finished board (Figure 8).

These tests also showed that particleboard was also a

significant source of emissions from the finished veneered

particleboard.

Two studies are currently underway to evaluate lowemitting surface finishes and engineered wood materials.

The goal is to identify low-emitting materials that may be

substituted for the existing finishes and engineered wood to

reduce emissions from the finished board. (EPA Contact:

Kelly W. Leovic, 919-541-7717, kleovic@engineer.

aeerl.epa.gov)

Figure 6. Emission Rates of Total VOCs from Selected

Types of Finished Engineered Wood after 24 Hrs

Figure 7. Comparison of Aldehyde and Ketone

Emission Rates at 24 Hrs and 31 Days

Figure 8. Emission Rates of Total VOCs from Various

Components of Finished Veneered Particleboard

(31 Days)
Inside IAQ, Spring/Summer 1996 Page 6

COST-EFFECTIVENESS OF ALTERNATIVE IAQ

CONTROL TECHNIQUES

IEMB is developing technical guidance that will assist users

in selecting and designing the most cost-effective

combination of IAQ control options in any specific

circumstance. The initial guidance will be general guidance

for commercial and institutional buildings, based on a

limited number of case studies. The first case study to be

conducted under this program has been partially completed.

A case study involves: 1) detailed definition of all key

building, HVAC, source, occupancy, and IAQ-related

parameters for the particular scenario to be studied; and 2)

a sensitivity analysis estimating the cost-effectiveness of

ventilation, air cleaning, and specific source management

steps as each of these parameters is varied.

The initial case study has addressed an existing 3-story

office building with an area of 10,000 ft2 (930 m2) per

story. To consider a range of possible interior

configurations, the first and third floors were assumed to

consist of enclosed offices around the perimeter, while the

second floor was open, containing modular workstations. A

suitable HVAC system was specified for the building, and

a variety of typical VOC emission sources were distributed

throughout the building. The incremental changes in total

annual costs (including annualized capital costs as well as

operating and maintenance costs) and the incremental

changes in annual VOC exposure to occupants at various

locations within the building, calculated as the IAQ control

approaches, were systematically varied. The parameters

varied in this sensitivity analysis included: the amount of

OA provided by the HVAC system; the efficiency of a

retrofit carbon-sorption VOC air cleaner; and the extent of

source management (which in this case consisted of the use

of low-emitting VOC sources).

The results for increased OA and for VOC air cleaners are

presented in Figure 9 for the case study building. The y-axis

shows cost-effectiveness, defined as the dollar cost per unit

reduction in individual exposure during the first year of

building occupancy – i.e., the total incremental cost for the

IAQ control step during the first year, divided by the

reduction in VOC exposure to the average occupant

(expressed as mg/m3-hr) during that year. Costeffectiveness is shown as a function of the percentage

reduction in exposure, relative to the baseline (“no-control”)

case, to identify the more efficient control measures.

Source management is not shown in Figure 9, since the

costs of “low-emitting” materials are difficult to estimate.

This figure will be used to determine what premium could

be paid for low-emitting materials before that source

management step would no longer be cost-competitive with

increased ventilation and air cleaning.

The baseline case corresponds to an OA supply of 5

cfm/person (2.35 L/sec), and no VOC air cleaning. The

five circles on the curve for increased OA ventilation in

Figure 9 correspond to increases in the OA supply to 20,

40, 60, 80, and 100 cfm/person (9.4, 18.8, 28.2, 37.6, and

47 L/sec). The three points marked on each curve for the air

cleaning system show the effects if the fixed charge of

carbon in the system were assumed to provide an average

VOC removal efficiency of 12, 50, or 88% over each of the

indicated carbon lifetimes.

The cost of air cleaning will depend significantly on the

frequency with which the carbon sorbent needs to be

replaced. That frequency, in turn, will depend on the nature

and the concentration of the VOCs. Due to this uncertainty,

a parametric family of curves is included for air cleaning,

showing the effect of alternative carbon replacement

frequencies. As shown in the figure, replacement at more

frequent intervals results in a substantial increase in cost. It

is reasonable to assume that the higher percentage

reductions will require more frequent replacement, and that

the lower reductions will require less frequent replacement.

The curve for increased ventilation shows a significant

increase in cost as the percentage reduction in exposure is

increased above 80% (corresponding to 80-100 cfm or 37.6

- 47 L/sec OA/person). This results from an increase in

HVAC retrofit capital cost when one increases to 100

cfm/person (47 L/sec).

Figure 9 suggests that, for building-wide VOC reductions

below about 70% in the study building during its first year,

increased OA ventilation is likely the more reasonable

approach, costing about $3 to 4 per mg/m3-hr reduction in

individual exposure. For building-wide reductions of 70 to

80%, VOC air cleaning could be competitive or perhaps even

slightly less expensive – with costs of about $2.50 to 4 per

mg/m3-hr – if the air cleaner is able to reliably achieve the

stated VOC removals with carbon lifetimes longer than 3

months. For very high reductions in exposure – above 80% –

it might be expected that the costs with either ventilation or air

cleaning might increase to about $7 per mg/m3-hr. In the case

of ventilation, this increase results from the required

replacement of existing HVAC equipment; in the case of air

cleaning, it results from the expected increase in carbon

replacement frequency. (EPA Contact: Bruce Henschel, 919-

541-4112, bhenschel@ engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1996 Page 7

50 55 60 65 70 75 80 85 90 95 100

0

1

2

3

4

5

6

7

8

9

10

11

1-month carbon lifetime

3-month carbon lifetime

6-month carbon lifetime

 KEY:

Increased OA Ventilation

VOC Air Cleaning

% Reduction in VOC Exposure by Average Occupant During First Year

Cost-Effectivness:

$ per mg/m3-hr reduction in VOC exposure by

average occupant during first year of occupancy

Figure 9. Cost-effectiveness of Increased OA Ventilation and of VOC Air Cleaning in the 3-story Office Building

(Assumptions: Equipment Lifetime - 10 years; Interest Rate - 7%; Cost of Electricity - $0.06/kWh)

QUALITY ASSURANCE FOR EPA’S IAQ RESEARCH

IEMB research covered in Inside IAQ responds to EPA quality

assurance (QA) requirements mandated by EPA Order 5360.1,

which establishes policy and program requirements for the

conduct of QA for all environmentally related measurements

performed by or for EPA. Its primary goal is to ensure that all

measurements supported by EPA produce data of known quality.

IEMB researchers use systematic planning to develop

acceptance or performance criteria for data collection whether it

is collected in the laboratory, in the field, or is produced by

models using information obtained from the literature. 

Many of IEMB’s research programs are carried out in on-site

facilities which include small chambers, a large chamber, and a

test house. All IEMB facilities have established fully functional

facility operating manuals as guidance documents to operations.

These facility manuals describe laboratory design specifications

and equipment, personnel capabilities and work capacity,

planning protocols, operating procedures, QA and quality control

requirements, and health and safety requirements. They also

contain test plan matrices including schedules and milestones.

They are living documents kept current, and once a year they are

formally reviewed and updated.

IEMB extramural research occurs off-site using the services of

contractors or cooperators. This work is performed via

contracts, cooperative agreements, or interagency agreements

(IAGs). Research using “in-kind” resources can occur via

cooperative research and development agreements (CRADAs) or

memoranda of understanding (MOU). When cooperating with

other federal agencies or organizations, EPA works with the

agency or organization to establish adequate QA requirements.

IEMB personnel produce various work products. Research

results are disseminated in published reports, at technical

meetings, or in the technical literature. EPA publications that

report measurement data contain sections discussing the quality

of the data in the report. The quality section discusses data

quality indicators such as accuracy (measurement system bias),

precision, completeness, representativeness, and comparability of

data. In quality research, standard sampling and analysis

methods are used where feasible, although because of the cutting

edge nature of some research, some methods may be developed

as the work progresses. Instruments are calibrated, and quality

control checks are performed periodically to keep the

measurements on track. Audits may be performed by QA

personnel as an independent check on performance. All of these

topics may be among the indicators of quality discussed in the

QA section of published reports.

Another product of IEMB research is computer models which

can predict the possible outcomes of various environmental

measurements using as input the often vast databases on the

subject in the technical literature. Care is taken that the

mathematical manipulations of the data produced by the

software are those intended. (EPA Contact: Shirley Wasson,

919-541-1439, swasson@ engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1996 Page 8

1.35μg

m

3

-200 -100 0 100 200 300 400

0

5

10

15

20

25

30

35

Bedroom

Den

Outdoors

Elapsed Hours

Conc. (ug/m3)

EMISSIONS OF CARBONYL COMPOUNDS FROM

LATEX PAINT

Emissions of carbonyl compounds from an interior latex paint

were investigated in IEMB’s test house. A white flat latex

paint purchased from a local store was applied to the walls of

a bedroom in the test house. The windows were open for the

first 4 hours, and a box fan was placed in one of the windows.

To determine the concentrations of carbonyl compounds, air

samples were collected on dinitrophenylhydrazine (DNPH)

cartridges and analyzed by high performance liquid

chromatography (HPLC). The OA samples were taken in the

backyard; indoor samples were taken from the painted

bedroom and the den area of the house.

Three carbonyl compounds were consistently found in the OA

samples and seven in the indoor samples (see Table 2). Trace

amounts of methacrolein [methacrylaldehyde

CH=C(CH3)CHO] were found in the OA samples.

Crotonaldehyde (2-butenal, CH3=CHCHCHO) was found in

the indoor air samples after paint application, but only in the

painted room on day 1. Low levels of butanone (methyl ethyl

ketone, CH3COCH2CH3) and butanal (CH3CH2CH2CHO)

were found in indoor samples before and after painting.

During this test, indoor concentrations of carbonyl compounds

were higher than outdoor concentrations. After paint

application, indoor formaldehyde concentrations in the painted

bedroom increased slightly (less that 30%). Among the seven

carbonyl compounds listed in Table 2, only the acetaldehyde

concentration changes were significant (see Figure 10). The

levels of carbonyl compound concentrations in the den are

consistently lower than those in the bedroom. However, all the

indoor carbonyl compound concentrations decreased to the

background indoor levels within 24 hours. (EPA Contact: John

Chang, 919-541-3747, jchang@ engineer.aeerl.epa.gov)

Table 2. Carbonyl Compounds Measured Indoors and

 Outdoors During Latex Paint Application *

Compound Outdoors

Inside

(Before Test)

Inside

(During Test)

Formaldehyde Yes Yes Yes

Acetaldehyde Yes Yes Yes

Acetone Yes Yes Yes

Propanal No Yes Yes

Benzaldehyde No Yes Yes

Pentanal No Yes Yes

Hexanal No Yes Yes

* Minimum Quantification Limit = 

Figure 10. Acetaldehyde Concentration Profile (paint

was applied at 0 hours)

GLOSSARY OF ACRONYMS

APPCD-Air Pollution Prevention &

Control Division

CFM-Cubic Feet per Minute

CFU-Colony Forming Units

CRADA-Cooperative Research and

Development Agreement

DNPH-dinitrophenylhydrazine

FS-Floating Slab

HPLC-High Performance Liquid

Chromatography

HVAC-Heating, Ventilating, and AirConditioning

IAG-Interagency Agreement

IAQ-Indoor Air Quality

IEMB-Indoor Emissions Management

Branch

IMA-Inhibitory Mold Agar

MOU-Memoranda of Understanding

NRMRL-National Risk Management

Research Laboratory

NTIS-National Technical

Information Service

OA-Outdoor Air

QA-Quality Assurance

RAETRAD-Radon Emanation and

Transport into Dwellings

RH-Relative Humidity

SSW-Slab-In-Stem Wall 

VOC-Volatile Organic Compound
Inside IAQ, Spring/Summer 1996 Page 9

SUMMARIES OF RECENT PUBLICATIONS

This section provides summaries of recent

publications on EPA’s indoor air research.

The source of the publication is listed after

each summary. Publications with NTIS

numbers are available (prepaid) from the

National Technical Information Service

(NTIS) at : 5285 Port Royal Road,

Springfield, VA 22161, 703-487-4650 or

800-553-6847.

Demonstration of Radon Resistant

Construction Techniques, Phase II-Subslab

mitigation systems were installed (in

accordance with draft standards) in 15 new

Florida houses in 1992. Soil radon levels

ranged from just under 500 to over 8000

pCi/L. Evaluation of the systems showed

that: 1) all systems extend negative pressure

to practically all areas under the slab; 2)

slabs tended to crack less than expected; and

3) intact vapor barriers under new houses

prevent radon intrusion through slab cracks

in most instances, but slab pipe penetrations

not sealed in accordance with standards can

contribute to relatively high indoor radon

levels. Eleven mitigation systems were

installed using ventilation matting, and four

systems used a wellpoint suction pipe. Both

systems performed well if carefully installed.

The highest indoor radon level with the

mitigation system capped off was 5.6 pCi/L

over 48 hours. Ten houses were under 2.9

pCi/L and did not require activation of their

mitigation systems. Five houses required

activation of their mitigation systems. All

houses are currently under 2.9 pCi/L.

Source: EPA Report, EPA-600-R-95-159,

NTIS PB96-121512, November 1995. (Lead

Author: James L. Tyson; EPA Contact:

David C. Sanchez, 919-541-2979,

dsanchez@ engineer.aeerl. epa.gov)

Entrainment by Low Air-Liquid Ratio

Effervescent Atomizer Produced SpraysThis paper describes entrainment into sprays

produced by an aerosol consumer product

dispenser that allows substitution of water for

VOC solvents and air for hydrocarbon

propellants. Experimental data are analyzed,

along with measured momentum rate data.

The analysis shows that dimensionless

entrainment by sprays produced using this

type of atomizer is accurately predicted,

using: 1) distance along the spray axis; 2)

exit orifice diameter; 3) spray momentum

rate at the exit orifice; 4) density of the

entrained air; 5) entrained gas mass flow

rate; 6) mass flow rate of liquid exiting the

dispenser; and 7) an entrainment number

whose value is 0.15 ± 0.056. Source:

Proceedings of Institute for Liquid

Atomization and Spray Systems, May 1996.

(Lead Author: Jeff J. Sutherland; EPA

Contact: Kelly W. Leovic, 919-541-7717,

kleovic@engineer .aeerl.epa.gov)

Evaluation of Radon Emanation from Soil

with Varying Moisture Content in a Soil

Chamber-Measurements of the emanation

coefficient and diffusion of radon in soil

contained in a 2 by 2 by 4 m chamber using

a range of moisture contents are described.

In addition, equal amounts of well-mixed

over-dried soil were placed in 20 L

aluminized gas-sampling bags, and after

approximately 1 month of in-growth, radon

samples were taken, after which water was

added, and another period of in-growth and

sampling followed. The emanation

coefficients and radon concentrations in the

gas bag experiment were observed to

increase with increasing moisture content

and then decrease before reaching saturated

conditions. The emanation and diffusion

effects on the radon concentration soil

gradient were identified for this sandy soil

having approximately 200 Bq kg -1 radium

and a soil density of 1682 kg m-3. Source:

Accepted for publication in Environment

International, Alexandria, VA, January

1996. (Lead Author and EPA Contact: Marc

Y. Menetrez, 919-541-7981, mmenetrez@

engineer.aeerl. epa.gov)

Growth Evaluation of Fungi (Penicillium

and Aspergillus ssp.) on Ceiling Tiles-The

potential for fungal (Penicillium and

Aspergillus ssp.) growth on four different

types of ceiling tiles was evaluated in static

chambers. It was found that even new

ceiling tiles could support fungal growth

when at equilibrium with a RH as low as

85% and corresponding moisture content

greater than 2.2%. Used ceiling tiles

appeared to be more susceptible to fungal

growth than new ones. In the 70% RH

chamber with wetted tiles under slow-drying,

non-equilibrium conditions, fungi could still

proliferate as long as the moisture level in

the ceiling tiles was adequate. Fungal growth

could be limited if the wetted ceiling tiles

were dried quickly and thoroughly. Source:

Atmospheric Environment, 29, 17, 2331-

2337, 1995. (Lead Author and EPA Contact:

John Chang, 919-541-3747, jchang@

engineer.aeerl.epa.gov)

HVAC Systems as a Tool in Controlling

Indoor Air Quality: A Literature ReviewThis report reviews the literature on the use

of HVAC systems to control IAQ. One

conclusion of the review is that HVAC

systems often contribute to indoor air

pollution because of 1) poor system

maintenance, 2) overcrowding or the

introduction of new pollution-generating

sources within buildings, and 3) the location

of OA intakes near ambient pollution

sources. Additionally, failure to trade off

between energy conservation and employee

productivity may result in increased IAQ

problems. Source: EPA Report, EPA-600/R95-174, NTIS PB96-140561, December

1995. (Lead Author: Max M. Samfield; EPA

Contact: David C. Sanchez, 919-541-2979,

dsanchez@ engineer.aeerl .epa.gov)

Measurement of Indoor Air Emissions from

Dry-Process Photocopy Machines- A

standard test method to measure emissions

from office equipment is being developed in

order to investigate pollution prevention

approaches for reducing emissions (e.g.,

ozone, VOCs, and particles). Initial results

from four dry-process photocopy machines

indicate that the method provides acceptable

performance for characterizing emissions,

can adequately identify differences in

emissions between machines, and is capable
Inside IAQ, Spring/Summer 1996 Page 10

of measuring both intra- and inter-machine

variability in emissions. The compounds

with the highest emission rates overall were

ethylbenzene (28,000 Fg/hour), m,p-xylenes

(29,000 Fg/hour), o-xylene (17,000 Fg/hour),

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

styrene (12,000 Fg/hour). Although many of

the same compounds tended to be emitted

from each of the four photocopiers, the

relative contribution of individual

compounds varied considerably between

machines, with differences greater than an

order of magnitude for some compounds.

Ozone emissions ranged from 1,300 to

7,900 Fg/hour. Source: Journal of the Air &

Waste Management Association, September

1996 (Lead Author & EPA Contact: Kelly

W. Leovic, 919-541-7717 ,

kleovic@engineer.aeerl. epa.gov)

Re-Entrainment and Dispersion of

Exhausts from Indoor Radon Reduction

Systems: Analysis of Tracer Gas DataTracer gas studies were conducted around

four model houses in a wind tunnel and one

house in the field to quantify re-entrainment

and dispersion of exhaust gases released

from residential radon reduction systems.

Field re-entrainment tests suggest that active

soil depressurization systems exhausting at

grade level can contribute indoor radon

concentrations 3 to 9 times greater than

systems exhausting at the eave. With a high

exhaust concentration of 37,000 Bq/m3, the

indoor contribution from eave exhaust reentrainment may be only 20 to 70% of the

national average ambient level in the U.S.

(about 14 Bq/m3), while grade-level exhaust

may contribute 1.8 times the average. The

grade-level contribution would drop to only

0.18 times ambient if the exhaust were 3,700

Bq/m3. Wind tunnel tests of exhaust

dispersion outdoors suggest that grade-level

exhaust can contribute mean concentrations

beside houses averaging 7 times greater than

exhaust at the eave, and 25 to 50 times

greater than exhaust midway up the roof

slope. With 37,000 Bq/m3 in the exhaust, the

highest mean concentrations beside the

house could be less than or equal to the

ambient background level with eave and

mid-roof exhausts, and 2 to 7 times greater

with grade exhausts. Source: Indoor Air,

5(4):270-284 (1995). (Lead Author and EPA

Contact: D.B. Henschel, 919-541-4112,

bhenschel@engineer.aeerl. epa.gov)

Residential Radon Resistant Construction

Feature Selection System-This report

describes a proposed residential radon

resistant construction feature selection

system that consists of engineered barriers to

reduce radon entry. Proposed standards in

Florida require radon resistant features in

proportion to regional soil radon potentials.

The effectiveness of different radon control

features was estimated from new laboratory

measurements, analyses of new and previous

house studies, and mathematical model

simulations. The laboratory measurements

characterized five polyethylene subslab

membranes. The analyses showed that both

monolithic-slab (mono) and Slab-in-Stem

Wall (SSW) foundation designs can

passively control indoor/subslab radon ratios

to average levels that are slightly lower than

measurements in other houses the previous

year, and two to four times lower than ratios

from earlier studies. The mono design offers

about twice as much passive radon

resistance as SSW designs. A Florida radon

protection map was developed to show

where the active and passive features are

needed. Source: EPA Report, EPA-600/R96-005, NTIS PB96-153473, February 1996.

(Lead Author: Kirk K. Nielson; EPA

Contact: David C. Sanchez, 919-541-2979,

dsanchez@ engineer.aeerl.epa.gov)

Site-Specific Characterization of Soil

Radon Potentials-Empirical measurements

suggest that the precision of soil radon

measurements is marginal, leaving an

uncertainty of about a factor of 2 in sitespecific estimates. Although this may be

useful for some applications, it probably is

inadequate for most decisions about

construction of radon-resistant features.

More detailed site characterization (soil

borings and measurements of radium,

emanation, moisture, and permeability

profiles) can improve precision; however, the

additional expense may not be justified in

comparison to the cost of installing the

features. Field tests of soil radon flux and

moisture measurements were conducted at

26 house sites in Polk County, Florida, to

evaluate their utility in predicting sitespecific radon potentials. Results showed

localized trends in radon potential that

compared well with mapped radon

potentials in some cases, but not in others.

For the 26 houses, the site-specific radon

potentials averaged twice the potentials from

the generalized radon maps. Source: EPA

Report, EPA-600/R-95-161, NTIS PB96-

140553, November 1995. (Lead Author:

Kirk K. Nielson; EPA Contact: David C.

Sanchez, 919-541-2979, dsanchez@

engineer.aeerl.epa.gov)

Status of EPA’s Bioresponse-Based Testing

Program-Since 1990 EPA has been

investigating the feasibility of using

biological methods based on human, animal,

or in vitro responses to characterize sources

of indoor air emissions. The “bioresponse”

methods being evaluated measure odor and

sensory irritation of mucosal tissues in the

eyes, nose, and upper airways. Chambers for

creating controlled emissions from sources

are basically the same as those used for

traditional studies of emission rates and

chemical compositions. Studies of human

subject responses to known odorous or

sensory irritant chemicals using nose-only,

eye-only, facial, and whole-body exposures

are providing baseline data against which

animal and in vitro results will be validated.

The animal and in vitro methods being

investigated measure changes in respiratory

patterns and chemosensory evoked

potentials. The status of current and future

projects is reported. Source: American

Society of Testing & Materials publication

STP1287, 1996. (Lead Author and EPA

Contact: W. Gene Tucker, 919-541-2746,

gtucker@engineer.aeerl. epa.gov)

Test Cell Studies of Radon Entry-This

report compares slab-in-stem wall (SSW)

with floating slab (FS) construction

practices, measures radon transport and

entry for model testing, develops protocols

relevant to depressurized radon measurements, and determines the effect of high

radium fill soil on indoor radon. The indoor

radon concentrations in the FS cell were 3.5

times higher than those in the SSW cell.

These results agreed with predictions by a

radon entry and transport (RAETRAD)

model. Whole building stresses and slab area

and crack length radon entry were

measured, and they yielded comparable

results. Experiments in the fill study suggest

that the amount of emanating soil radium is

a good predictor for radon entry into a

structure. Source: EPA Report, EPA-600/R96-010, NTIS PB96-153549, February 1996.

(Lead Author: Ashley D. Williamson; EPA

Contact: David C. Sanchez, 919-541-2979,

dsanchez@ engineer.aeerl. epa.gov)
Inside IAQ, Spring/Summer 1996 Page 11

CONTACTS IN IEMB

Name Research Areas Phone E-mail 

Michael C. Osborne Branch Chief 919-541-4113 mosborne@*

John C. S. Chang Biocontaminants, VOC Source/Sink Characterization, VOC

Emissions Modeling

919-541-3747 jchang@*

D. Bruce Henschel Cost Analysis of IAQ Control Techniques, Building Energy

Modeling, Radon Reduction in Existing Houses

919-541-4112 bhenschel@*

Betsy M. Howard Pollution Prevention, Particle Board, Large Chamber Testing,

Conversion Varnishes

919-541-7915 bhoward@*

Mark A. Mason Bioresponse Methods Development, Chemical Source Characterization, Large Chamber Testing919-541-4835 mmason@*

Marc Y. Menetrez Large Building Measurements (IAQ, Ventilation, Building

Dynamics HVAC, Diagnostic Strategy) 

919-541-7981 mmenetrez@*

Ronald B. Mosley Indoor Air Pollutants Originating in Soil, Mathematical Modeling,

Indoor Particles, Soil Contaminants

919-541-7865 rmosley@*

Richard B. Perry Radon Diffusion Measurement, Test Method Development,

Ventilation Systems Research

919-541-2721 rperry@*

Leslie E. Sparks IAQ and Exposure Modeling, Air Cleaners, Indoor Particles 919-541-2458 lsparks@*

W. Gene Tucker Control of IAQ, ASHRAE Standard 62, Bioresponse Methods,

Source Emissions, Indoor/Outdoor Particles

919-541-2746 gtucker@*

James B. White Development of Low-Emitting/Low-Impact Sources, IAQ Emission

Source Catalog & Database, IAQ & Life Cycle Assessment, Environmental Resources Guide, Expert Systems for Facilities Design &

Operation Development of CADD-based LCA for IAQ, Textiles

919-541-1189 jwhite@*

* (all E-mail @) engineer.aeerl.epa.gov
Call for Papers

Engineering Solutions to Indoor Air Quality Problems

The second biennial Engineering Solutions to Indoor Air Quality Problems Symposium, an international symposium cosponsored by

the Air & Waste Management Association and EPA’s National Risk Management Research Laboratory, will be held July 21-23, 1997,

at the Sheraton Imperial Hotel and Conference Center in Research Triangle Park, NC. Papers are invited on the following topics:

! Managing the Risk of Indoor Air Pollution

! 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

! Ventilation

! HVAC Systems as Sources of

Indoor Air Pollution

! Air Duct Cleaning

! Particles in Indoor Air

! Indoor Air Quality Modeling

! Costs of Managing Indoor Air Quality

The two and a half-day symposium will consist of one general session so that participants will be able to attend all sessions. A poster

session, continuing education courses, and an exhibition of related products and services are also planned.

Send abstracts of 200-300 words by January 10, 1997 to: Kelly W. Leovic, U.S. EPA, MD-54, Research Triangle Park, NC 27711;

Telephone (919) 541-7717; Fax (919) 541-2157; E-mail: kleovic@engineer.aeerl.epa.gov. Abstracts should include paper title and

author(s) names, address(es), and phone, fax number(s), and e-mail address (if applicable).

United States

Environmental Protection Agency

Indoor Environment Management Branch

MD-54

Research Triangle Park, NC 27711

Official Business

Penalty for Private Use

$300

EPA/600/N-96-002, Spring/Summer 1996

An Equal Opportunity Employer

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POSTAGE AND FEES PAID

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