Inside IAQ, Fall/Winter 2002 Page 1

Indoor Air Quality Problems

and Engineering Solutions

Symposium

July 21-23, 2003

Research Triangle Park, NC

(See Page 12 for Call for Papers)

United States Environmental Office of Research and Development

Protection Agency Research Triangle Park, NC 27711

EPA/000/X-00/000 Fall/Winter 2002 

 EPA Inside IAQ

EPA's Indoor Air Quality Research Update

In This Issue Page

A Small Chamber Test Method for the Measurement

 of Volatile Organic Compounds and Hazardous

 Air Pollutants from Alkyd and Latex Paints ......... 1

Fine Particle Emissions from Burning Incense ........ 2

Parameter Estimation for Indoor Source

 Models in the Absence of Experimental Data ...... 2

Summary of Recent Publications ................... 8

A Small Chamber Test Method for the Measurement of Volatile Organic Compounds and

Hazardous Air Pollutants from Alkyd and Latex Paints

Americans spend about 90% of their time indoors, where

concentrations of pollutants are often much higher than they

are outdoors. It is not surprising, therefore, that risk

assessment and risk management studies have shown that

indoor environmental pollution poses significant risks to

human health. 

The U.S. Environmental Protection Agency (EPA) has

evaluated a number of indoor materials and products as

potential sources of indoor air pollution under the Indoor

Air Source Characterization Project (IASCP). Interior

architectural coatings, especially alkyd and latex paints,

were identified as potentially high-risk indoor sources by

the Source Ranking Database developed under the IASCP.

EPA conducted a literature survey and found that there was

a lack of reliable and consistent paint emission data for

developing and evaluating risk management options.

Further investigation showed that a standardized test

method needed to be developed so that testing laboratories,

researchers, and paint manufacturers could generate and

report emission data that were complete, consistent, and

comparable. 

Between 1995 and 1999, EPA’s National Risk Management

Research Laboratory (NRMRL) conducted a paint emission

characterization research program. The program was

devoted to developing, verifying, and demonstrating a small

chamber test method for the measurement of volatile

organic compound (VOC) and hazardous air pollutant

(HAP) emissions from alkyd and latex paints. The test

method has been documented and submitted to the

American Society for Testing and Materials (ASTM) for

adoption as a standard practice. 

This report briefly summarizes the resulting test method,

presents new findings, and describes the key results

generated by NRMRL as it assessed emissions from alkyd

and latex paints. The report is divided into four parts. After

introducing the study and providing background 

(Continued on Page 3)
Inside IAQ, Fall/Winter 2002 Page 2

Fine Particle Emissions from Burning Incense

Recent studies have shown that human exposure to fine

particulate matter (PM) constitutes a potential health hazard

and that some indoor PM is from unknown sources.

Principal adverse health effects associated with PM

exposure are increased respiratory symptoms, increased

respiratory illnesses, increased respiratory morbidity in

asthmatics, and increased mortality in persons with COPD

(chronic obstructive pulmonary disease). EPA initiated

research in 1999 to identify and characterize potentially

important indoor PM sources. As part of this effort, incense

burning was investigated, because, according to the

literature, it is a significant source of PM and has been

linked to various illnesses. Studies in the literature have

found harmful health effects associated with incense smoke

including cancers, asthma, dermatitis, mutagenesis, and

genotoxic effects.

Incense is burned to produce fragrances or mask odors, and

burning incense is incorporated in the rituals of several

different religions. Incense is burned inside homes and

places of worship on a daily basis by some large minority

populations in the U.S. and by large populations in other

countries. In the U.S., incense is burned in public places

including stores, shopping malls, and places of worship.

EPA has no regulations for incense smoke in indoor air.

A study was recently conducted to (1) determine the PM

emissions from different types of incense, and (2) estimate

the significance of human exposure to incense smoke. The

study did not directly examine the health effects of burning

incense. Results from the study were included in a paper

entitled “Characterization of Emissions from Burning

Incense” that was published in the international journal, The

Science of the Total Environment, Volume 295, pp. 51-67,

August 5, 2002. The study was conducted by the Indoor

Environment Management Branch in Research Triangle

Park, NC, and the authors were James Jetter, Zhishi Guo,

Jenia McBrian, and Michael Flynn.

In the study, scientists purchased 23 types of incense locally

and tested for PM emissions in a specially designed test

chamber. PM was collected on filters, from which the

emission rates were calculated. Using an indoor air quality

model, the emission rates were used to calculate the indoor

PM concentrations due to incense burning in homes. The

results were compared with ambient air quality standards.

Results from the study showed that emission rates for PM2.5

(particulate matter less than 2.5 micrometers in

aerodynamic diameter) ranged from 7 to 202 milligrams per

hour, and PM2.5 emission factors ranged from 5 to 56

milligrams per gram of incense burned. These results

suggest that burning incense emits fine PM in large

quantities. An indoor air quality model showed that, under

certain conditions, burning incense at home can result in

indoor concentrations of PM2.5 that far exceed the outdoor

concentrations specified by the NAAQS (National Ambient

Air Quality Standards), so incense smoke can pose a health

risk to incense users due to inhalation exposure of PM.

Risk is increased when exposure duration is long, room

ventilation is low, room size is small, burning time of the

incense is long, and emissions are high.

Providing information to consumers of incense products

could reduce health risks. Incense users may eliminate risk

by choosing not to burn incense. Users may reduce risk by

burning incense outdoors instead of indoors or by burning

incense in a well-ventilated area, such as under an operating

ventilation hood for a stove. Users may reduce risk by

burning incense for shorter periods of time, by increasing

room ventilation, by burning incense in a larger room, and

by burning incense with lower emissions.

For further information, contact Jim Jetter, (919) 541-4830,

jetter.jim@epa.gov.

Parameter Estimation for Indoor SourceModels in the Absence of Experimental Data

Estimating human exposure in the indoor environment

requires knowledge of pollutant penetration from outdoors

and emissions from indoor sources. In general, the latter

are more difficult to estimate because of the vast variety of

indoor sources. To account for the contribution of indoor

sources, one need indoor emission source models. Over 50

such models have been developed over the years. While

they represent a great achievement made by indoor air
Inside IAQ, Fall/Winter 2002 Page 3

quality (IAQ) modelers, there is certainly room for

improvement. A recent review by the author reveals that

many of these models have not been used in exposure

assessment programs, and that genuine predictive models

are still few. A major obstacle is the lack of methods to

estimate the model parameters in the absence of

experimental data. Only a fraction of the model parameters

( molecular weight, vapor pressure, Henry’s constant, etc.)

can be found from the literature. Estimation of the rest

parameters (diffusivity, mass transfer coefficient. etc.)

relies on quantitative structure-activity relationships

(QSARs) and other types of correlations. The author

recently compiled 48 published methods for estimating

parameters in the indoor source models and is developing

a Microsoft Windows-based computer program to

implement commonly used QSARs and other correlations,

among which are:

– first-order decay rate constants for organic solvent- and

water-based coating materials,

– diffusivity in air, water, and solids;

– solid/air partition coefficient;

– gas-phase, liquid-phase, and overall mass transfer 

coefficient;

– vapor pressure by compound class and carbon number;

– total pressure and partial pressure for petroleum-based

solvent;

– properties of air (density, viscosity, moisture contents,

etc.); and

– properties of water (vapor pressure and viscosity).

A beta version of this program will be available for user

testing in the Spring of 2003. It should be pointed out that

the existing methods cannot solve all the problems

associated with parameter estimation. Many parameters in

indoor source models can only be determined by

experiment. Thus, parameter estimation is a research area

that IAQ modelers should pay more attention to in the

future. In particular, research is needed to (1) develop new

methods, (2) refine the existing methods, (3) evaluate

existing methods for accuracy and uncertainty, (4)

recommend the best available methods.

For further information, contact Jim Jetter, (919) 541-

0185, guo.zhishi@epa.gov.

(Continued from Page 1)

information about existing literature on the subject paint

emissions testing, the report describes the developed

standard test method for characterizing organic compounds

emitted from paint. It also describes the results of

NRMRL’s tests on alkyd and latex paints.

Standardized Test Method

The standardized test method addresses the following key

issues:

•Storing and handling paint samples prior to analysis

•Analyzing paint in bulk (as a liquid)

•Selecting and preparing a paint substrate for testing

•Applying paint to a substrate to create a test specimen

•Establishing and controlling test conditions

•Sampling the VOC emissions from the painted specimen

•Analyzing the samples with chemical instruments

•Calculating emission rates/factors using experimental data

•Conducting quality assurance/quality control

The core experimental apparatus employed by the

standardized test method is a device called a Small

Environmental Test Chamber (“small chamber” for short).

A test chamber is a hollow box that may range in size from

a few liters to 5 m3. The chamber used at NRMRL is 53 L

(0.053 m3) in volume. Chambers with volumes greater than

5 m3 are defined as “large”—they may reach the scale of an

entire room. The small chamber, on the other hand, is an

apparatus suited to the spatial and financial constraints of

a typical laboratory environment. It is also more convenient

to operate than a large chamber. An environmental chamber

test facility designed and operated to determine organic

emission rates from paints should contain the following:

test chambers, clean air generation system, monitoring and

control systems, sample collection and analysis equipment,

and standards generation and calibration systems. The

purpose of these components is to provide a controlled

environment for conducting emissions testing that can

reflect common indoor air conditions.

The standardized test method includes a series of

procedures and guidelines for preparing a painted test

specimen. Procedures for handling and storing the paint to

be tested were established to guard against the possibility of

evaporative losses, stratification, and property changes. A

modified version of EPA Method 311 (40 CFR, 1996) was

adopted for the bulk analysis of paints, to facilitate the

experimental design of the emissions test and the selection

of sampling and analytical techniques. Instead of traditional

test substrates such as glass, stainless steel, and aluminum,

common indoor materials such as gypsum board and wood

are recommended in the method for creating realistic and
Inside IAQ, Fall/Winter 2002 Page 4

representative testing samples. Either a roller or a brush

should be used to apply the paint to the substrate. A

protocol was developed to quantify the amount of the paint

applied so that the emission data can be consistent and

comparable. 

The “time zero” for the start of an emission test is

established when the chamber door is closed (immediately

after placing the test specimen inside the chamber). The

small chamber should be operated to match the actual

environmental conditions atwhich people paint the interiors

of houses. The standardized method guides investigators in

setting up their sampling protocols. The instructions help to

ensure that investigators collect an adequate quantity of

chamber air samples on the appropriate sampling media.

The method describes several kinds of analytical

instruments that can be used to determine the amounts and

kinds of VOCs in the collected sample. Data reduction

techniques and an example of an emission model are

included in the method—it describes the mathematical

procedures used to convert the analytical results into

emission rates and emission factors. In addition, the method

provides guidelines for reporting and quality assurance.

These guidelines should help investigators compile their

results in a consistent and complete fashion that allows for

comparison or repeat emissions testing of similar or new

architectural coatings.

Alkyd Paints

Alkyd paint continues to be used indoors because it has

desirable properties such as durability, gloss, gloss

retention, and fast drying. NRMRL has employed the newly

developed standardized test method to conduct research that

characterizes VOC emissions from alkyd paint. NRMRL

used the results of its paint emissions tests to develop

source emission models. These models, in turn, were used

for the assessment of indoor exposure levels and risk

management options.

The first test series that NRMRL performed on alkyd paints

was integrated into the process of developing and validating

its new standard practices for paint testing. The tests

involved one primer and three alkyd paints. Bulk analysis

indicated that the alkyd primer and two of the three paints

tested contained more than 100 different VOCs, primarily

straight-chain alkanes, with decane and undecane being the

predominant compounds. The third paint had more

branched alkanes. All four coatings contained low levels of

aromatic compounds. The total VOC content of the liquid

paints ranged from 32% to 42%. Measurements of the total

VOC levels in the liquid coatings by gas

chromatography/mass spectrometry (GC/MS) agreed well

with manufacturers’ data.

Mass balance calculations were conducted to compare the

bulk analysis results and chamber emission data to evaluate

the recovery. It was found that for total VOC, the majority

(greater than 80%) of the mass in the applied paint could

be accounted for in the subsequent air emissions. The data

for the more abundant compounds (e.g., nonane, decane,

and undecane) in the paint suggest that there was a margin

of error of ± 20% in measuring these recoveries.

Due to the relatively high VOC content and fast emission

pattern, peak concentrations of total VOC as high as 10,000

mg/m3

 were measured during small chamber emissions tests

with a loading factor of 0.5 m2

/m3

 and an air exchange rate

of 0.5 h-1. Over 90% of the VOCs were emitted from the

primer and paints during the first 10 hours following

application.

A series of tests were performed to evaluate those factors

that may affect emissions following application of the

coatings. It was found that the type of substrate (glass,

wallboard, or pine board) did not have a substantial effect

on the emissions with respect to peak concentrations, the

emissions profile, or the mass of VOC emitted from the

paint. The emissions from paint applied to bare pine board,

a primed board, and a board previously painted with the

same paint were quite similar. There were differences

among the emissions from the three different paints, but the

general patterns of these emissions were similar. The effect

of other variables, including film thickness, air velocity at

the surface, and air exchange rate, were consistent with

theoretical predictions for gas-phase, mass-transfercontrolled emissions. 

Results from the testing performed in this study are being

used to develop computational methods for estimating the

emission rate of total VOCs from solvent-based coating

products used indoors. The database on total VOC emission

from alkyd paint should also be useful for others involved

in model development and validation.

In addition to studying the effects of substrates and other

environmental variables on total VOC emissions, small

environmental chamber testswere conductedto characterize

the emissions of a toxic chemical compound—methyl ethyl

ketoxime (MEKO)—from three different alkyd paints. The

data resulting from these tests facilitated the development

of a set of risk management options for MEKO.

Methyl ethyl ketoxime, another name for 2-butanone oxime

or ethyl methyl ketoxime [CH3C(NOH)C2H5

, CAS Registry

No. 96-29-7], is often used by paint manufacturers as an
Inside IAQ, Fall/Winter 2002 Page 5

additive to interior alkyd paints (Weismantel, 1981; Turner,

1988). MEKO has been found to be a moderate eye irritant

(Krivanek, 1982). It was also the subject of a Section 4 test

rule under the Toxic Substances Control Act (Fed. Regist.,

1986). A number of toxicological endpoints have been

evaluated by testing conducted under the test rule (Fed.

Regist., 1989). MEKO demonstrated carcinogenic activity

in long-term inhalation studies, causing liver tumors in both

rats and mice.

MEKO acts as an anti-skinning agent (or anti-oxidant) that

prevents oxidative drying or skinning of the alkyd paint to

improve stability in the can. Usually, the MEKO content in

a paint is less than 0.5% (Krivanek, 1982). Due to its

relatively high volatility (its boiling point is only 152oC),

the majority of the MEKO in the paint is expected to be

released into the surrounding indoor air after painting to

allow the paint to dry properly on the painted surfaces. The

effects of MEKO emissions on indoor air quality (IAQ) and

associated exposure risk depend on characteristics such as

emission rates and patterns. 

Bulk analysis showed that the MEKO content in alkyd

paints can be as high as several mg/g. Material balance from

the chamber tests indicated that the majority (greater than

68%) of the MEKO in the paint applied was emitted into

the air. MEKO emissions occurred almost immediately after

each alkyd paint was applied to a pine board. Due to the fast

emission pattern, more than 90% of the MEKO emitted was

released within 10 hours after painting. The peak

concentrations of MEKO in chamber air correlated well

with the MEKO content in the paint.

The chamber data were simulated by a first-order decay

emission model that assumed that the MEKO emissions

were mostly gas-phase mass-transfer-controlled. The firstorder decay model was used as an input to the continuousapplication source term of an IAQ model to predict indoor

MEKO concentrations during and after the application of an

alkyd paint in a test house. The predicted test house MEKO

concentrations during and after the painting exceeded a

suggested indoor exposure limit of 0.1 mg/m3 for all three

paints. The predicted MEKO concentrations also exceeded

the lower limit of a suggested sensory irritation range of 4

to 18 mg/m3 with two of the three paints tested. The

elevated MEKO concentrations can last for more than 10 h

after the painting is finished. The model was also used to

evaluate and demonstrate the effectiveness of risk reduction

options. These options involved selecting lower MEKO

paints and establishing higher ventilation levels during

painting. The higher ventilation should be maintained about

2 h after the painting is finished to avoid exposure to

residual MEKO emissions.

In addition to total VOC and MEKO emissions, the

unpleasant “after-odor” which can persist for weeks after

application of alkyd paint has been a cause of IAQ

concerns. Three different alkyd paints were tested in small

environmental chambers to characterize the aldehyde

emissions. Emission data indicated that significant amounts

of odorous aldehydes (mainly hexanal) were emitted from

alkyd paints during the air-drying period. Bulk analyses

showed that the alkyd paint itself contained no aldehydes.

Mass balance calculations indicated that any aldehydes

emitted should have been produced after the paint was

applied to a substrate. The aldehydes emission patterns

were consistent with the theory that the aldehydes were

formed as byproducts from spontaneous autoxidation of

unsaturated fatty acids in the applied paint. Chamber data

showed that the major volatile byproducts generated by the

drying of the alkyd paints were hexanal, propanal, and

pentanal. These results facilitated the development of an

exposure assessment model for hexanal emissions from

drying alkyd paint.

The hexanal emission rate was simulated by a model that

assumed that the autoxidation process was controlled by a

consecutive first-order reaction mechanism with an initial

time lag. The time lag reflects an induction period after

painting during which little oxygen is taken up by the alkyd

coating. As the final byproduct of a series of consecutive

first-order reactions, the hexanal emission rate increases

from zero to reach a peak and is followed by a slow decay.

This model was confirmed by chamber concentration data.

The modeling results also showed that the hexanal

emissions were controlled mostly by the chemical reactions

that formed intermediates (i.e., the precursors to hexanal

production).

An IAQ simulation that used the emission rate model

indicated that the hexanal emissions can result in prolonged

(several days long) exposure risk to occupants. IAQ

simulation indicated that the hexanal concentration due to

emissions from an alkyd paint in an indoor application

could exceed the reported odor threshold for about 120

hours. The occupant exposure to aldehydes emitted from

alkyd paint also could cause sensory irritation and other

health concerns.

Latex Paints

The majority (over 85%) of the interior architectural

coatings used in the United States are latex paints. Previous

testing of latex paint emissions has focused on determining

cumulative mass emissions of VOCs. The purpose of

previous testing was to assess the effect of these paints on

the ambient air and to determine how they contributed to
Inside IAQ, Fall/Winter 2002 Page 6

photochemical smog (Brezinski, 1989). NRMRL’s concern

has been to estimate people’s time-varying exposure to

overall VOC levels and to specific VOCs from indoor latex

paints.

The first test series that NRMRL performed on latex paints

was integrated into the process of developing and validating

its new standard practice for paint testing. NRMRL’s small

chamber tests indicated that the organic emission patterns

of latex paints are very different from those of alkyd paints.

Bulk analysis showed that the total VOC content of a

commonly used latex paint is usually in the range of 2% to

5%, which is considerably lower than that of alkyd paints

(32% to 42%). Instead of alkanes, alkenes, and aromatics,

only several polar compounds such as glycols, alcohols, and

aldehydes were found in the latex paints. 

The chamber test results showed significant differences

between the emissions of the same latex paint applied to

two different substrates (a stainless steel plate and a gypsum

board). The amount of VOCs emitted from the painted

stainless steel was 2 to 10 times greater than the amount

emitted from the painted gypsum board during the 2-week

test period. After the first 2 weeks, over 90% of the VOCs

was emitted from the paint on the stainless steel plate but

less than 20% had left the gypsum board. The dominant

species in the VOCs emitted also changed from ethylene

glycol to 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate

when stainless steel was replaced with gypsum board. Data

analysis by a double-exponential model indicated that the

majority of the VOC emissions from the painted stainless

steel could be simulated by an evaporation-like

phenomenon with fast VOC emissions controlled by gasphase mass transfer. On the other hand, only a small

fraction of the VOCs emitted from the painted gypsum

board appeared to be controlled by the evaporation-like

drying process. The majority of the VOCs were emitted

after the painted gypsum board surface was relatively dry.

They were probably dominated by a slow, solid-phasediffusion-controlled mass transfer process. Long-term

experimental data indicated that it may take as long as 3.5

years for all the VOCs to be released from the paint applied

to the gypsum board.

The small chamber test results demonstrate that, when the

objective of a test is to provide emissions data that are

relevant to understanding a paint’s emissions behavior in

typical indoor environments, one should use “real”

substrates such as wood and gypsum board instead of

“ideal” substrates such as glass, aluminum, or stainless

steel. Proper choice of substrate is therefore crucial for

exposure and/or risk assessment studies involving indoor

latex paints.

NRMRL also used the small chamber test method to

evaluate a relatively new type of interior architectural

coating, the so called “low-VOC” latex paint. Low-VOC

paint has been used as a substitute for conventional latex

paints to avoid indoor air pollution. Low-VOC latex paints

are promoted for use in occupied hospitals, extended care

facilities, nursing homes, medical facilities, schools, hotels,

offices, and homes where extended evacuation of an entire

building section for painting would be particularly difficult

or undesirable.

Four commercially available low-VOC latex paints were

evaluated as substitutes for conventional latex paints. They

were evaluated by assessing both their emission

characteristics and their performance as interior wall

coatings. Bulk analysis indicated that the VOC contents of

the four paints (which ranged from 0.01% to 0.3%) were

considerably lower than those of conventional latex paints

(3% to 5%). EPA Method 24 (40 CFR, 1996) for

determining VOC content (commonly used by paint

manufacturers) is not accurate enough to quantify the VOC

contents of low-VOC latex paints for quality control and

product ranking purposes. Other methods such as EPA

Method 311 are more suitable, especially when individual

VOC content data are needed.

The fact that “low-VOC” paint had relatively low VOC

emissions was confirmed by small chamber emission tests.

However, the experimental data also indicated that three of

the four low-VOC latex paints tested either had some

inferior coating properties or emitted hazardous air

pollutants. Significant emissions of several aldehydes

(especially formaldehyde, which is a HAP) were detected

in emissions from two of the four paints. ASTM methods

were used to evaluate the paints’ coating performance

including hiding power, scrub resistance, washability,

drying time, and yellowing. The results indicated that one

of the four low-VOC paints tested showed performance

equivalent or superior to that of a conventional latex paint

used as control. It was concluded that low-VOC latex paint

can be a viable option to replace conventional latex paints

for prevention of indoor air pollution. However, certain

paints marketed as “low-VOC” may still emit significant

quantities of air pollutants, including HAPs. In addition,

some of these paints may not have performance

characteristics matching those of conventional latex paints.

Due to the use pattern of low-VOC paints proposed by their

manufacturers (i.e., partial occupancy during painting and

immediate re-occupation after painting), the intimate

exposure of sensitive occupants to the low-VOC latex paint

emissions (especially to HAPs such as formaldehyde) is of

special concern. Long-term environmental chamber tests
Inside IAQ, Fall/Winter 2002 Page 7

were performed to characterize the formaldehyde emission

profiles of a low-VOC latex paint. The formaldehyde

emissions resulted in a sharp increase of formaldehyde

concentrations within the chamber, rising to a peak

followed by transition to a long-term slow decay.

Environmental chamber data indicated that formaldehyde

emissions from a low-VOC latex paint can cause very high

(several ppm) peak concentrations in the chamber air. When

the paint was applied to gypsum board, the formaldehyde

emissions decayed very slowly after the initial peak, and the

emission lasted for more than a month. The results of these

tests allowed for the development of exposure assessment

emissions models to facilitate pollution prevention efforts

to reduce the amount of formaldehyde released by lowVOC paints.

A semi-empirical first-order decay in-series model was

developed to interpret the chamber data. The model

characterized the formaldehyde emissions from the paint in

three stages: an initial “puff” of instant release, a fast decay,

and a final stage of slow decay controlled by a solid-phase

diffusion process that can last for more than a month. The

semi-empirical model was used to estimate the amount of

formaldehyde emitted or remaining in the paint. It also

predicted the initial peak concentration offormaldehyde and

the time necessary for the formaldehyde to become depleted

from paint. Once the activity patterns of building occupants

were defined, the model was used for exposure risk

 assessment.

Additional small chamber tests were performed to

investigate the major sources of formaldehyde in the paint.

Through comparing emission patterns and modeling

outcomes of different paint formulations, a biocide used to

preserve one of the paints was identified as a major source

of the formaldehyde emissions. Chamber test results also

demonstrated that paint reformulation by replacing the

preservative with a different biocide for the particular paint

tested resulted in an approximately 55% reduction of

formaldehyde emissions. However, since other sources

(e.g., additives and binders) of formaldehyde are present in

the paint, biocide replacement can reduce only the longterm emissions. Short-term generation of high

concentrations of formaldehyde remains a problem.

Additional research is needed to identify other potential

sources of formaldehyde to completely eliminate

formaldehyde emissions from low-VOC paints.

For further information, contact John Chang, (919) 541-

3747, chang.john@epa.gov.
Inside IAQ, Fall/Winter 2002 Page 8

SUMMARIES OF RECENT PUBLICATIONS

Characterization of Emissions from

Burning Incense - The primary

objective of this study was to improve

the characterization of particulate

matter emissions from burning

incense. Emissions of particulate

matter were measured for 23 different

types of incense using a cyclone/filter

method. Emission rates for PM2.5

(particulate matter less than 2.5 [mu]m

in aerodynamic diameter) ranged from

7 to 202 mg/h, and PM2.5 emission

factors ranged from 5 to 56 mg/g of

incense burned. Emission rates were

also determined using an electrical low

pressure impactor (ELPI) and a small

electrostatic precipitator (ESP), and

emission rates were compared to those

determined using the cyclone/filter

method. Emission rates determined by

the ELPI method were consistently

lower than those determined by the

cyclone/filter method, and a linear

regression correlation was found

between emission rates determined by

the two methods. Emission rates

determined by the ESP method were

consistently higher than those

determined by the cyclone/filter

method, indicating that the ESP may

be a more effective method for

measuring semivolatile particle

emissions. A linear regression

correlation was also found between

emission rates determined by the ESP

and cyclone/filter methods. Particle

size distributions were measured with

the ELPI, and distributions were found

to be similar for most types of incense

that were tested. Size distributions by

mass typically ranged from

approximately 0.06 to 2.5 [mu]m in

aerodynamic diameter, with peak

values between 0.26 and 0.65 [mu]m.

Results indicated that burning incense

emits fine particulate matter in large

quantities compared to other indoor

sources. An indoor air quality model

showed that indoor concentrations of

PM2.5 can far exceed the outdoor

concentrations specified by the US

EPA's National Ambient Air Quality

Standards (NAAQS), so incense

smoke can pose a health risk to people

due to inhalation exposure of

particulate matter. Emissions of

carbon monoxide (CO), nitric oxide

(NO), and sulfur dioxide (SO2) were

also measured for seven types of

incense. Emission rates of the gaseous

pollutants were sufficient to cause

indoor concentrations, estimated using

the indoor air quality model, to exceed

the outdoor concentrations specified

by the NAAQS under certain

conditions. However, the incense

samples that were tested would fill a

room with thick smoke under these

conditions. Source: The Science of The

Total Environment, Vol. 295, Issue 1-

3, 51-67, 2002. (EPA Contact: Jim

Jett er, 919-541-48 3 0 ,

jetter.jim@epa.gov) 

Development of a Windows-based

indoor air quality simulation software

package A Microsoft Windows-based

indoor air quality (IAQ) simulation

software package has been developed

and has completed a small-scale beta

test and quality assurance review.

Tentatively named Simulation Tool

Kit for Indoor Air Quality and

Inhalation Exposure, or STKi for

short, this package complements and

supplements existing IAQ simulation

packages and is designed mainly for

advanced users. STKi Version 1

consists of a general-purpose

simulation program and four standalone, special-purpose pro-grams. The

general-purpose program performs

multi-zone,multi-pollutantsimulations

and allows gas-phase chemical

reactions. With a large collection of

models for sources, sinks, and air

filters/cleaners, it can perform

simulations for a wide range of indoor

air pollution scenarios. The specialpurpose programs implement

fundamentally based models, which

are often excluded from existing IAQ

simulation programs despite their

improved performance over statistical

models. In addition to performing

conventional IAQ simulation, which

generates time–concentration profiles,

STKi can estimate the adequate

ventilation rate when certain air

quality criteria are given, a unique

feature useful for product stewardship

and risk management. STKi will be

developed in a cumulative manner.

More special-purpose simulation

programs will be added to the package.

Key numerical methods used in STKi

are discussed. Ways to convert the

STKi programs into languageindependent simulation modules that

can be used by multi-pathway

exposure models are also being

explored. Source: Environmental

Modeling and Software, Vol. 15, 403-

410, 2000. (EPA Contact: Zhishi Guo,

919-541 0185 guo.zhishi@epa.gov)
Inside IAQ, Fall/Winter 2002 Page 9

Comparison of Methods for

Measuring Conce3ntrations of

Semivolatile Particulate Matter The

purpose of this study was to compare

methods for measuring concentrations

of semivolatileparticulate matter (PM)

from indoor-environment, small,

combustion sources. Particle

concentration measurements were

compared for methods using filters

and a small electrostatic precipitator

(ESP). Particle size distributions were

measured using an electrical lowp ress ure impactor (ELPI) .

Semivolatile PM was produced from

cigarette and incense smoke, and, for

comparison, a relatively nonvolatile

aerosol was produced from

polyalphaolefin oil. Results showed

that semivolatile PM concentrations

measured using the ESP method were

significantly higher than those

measured using the filter method. The

ESP method was shown to be a more

effective means of measuring

semivolatile PM under the test

conditions Source: “Proceedings: 9th

International Conference on Indoor

Air Quality and Climate” Monterey,

California June 30 – July 5, 2002

(EPA Contact: Jim Jetter, 919-541-

4830, jetter.jim@epa.gov) 

Air Toxic Emissions from a Vinyl

Shower Curtain Three static chamber

tests were performed to measure the

headspace concentrations of the

curtain when stored in a sealed

container. Four air toxics--toluene,

methyl isobutyl ketone (MIBK),

ethylbenzene, and phenol-- were

detected. Although the chamber

loadings varied by a factor of 3.1, the

average headspace equilibrium

concentrations differed by less than

32% among the three chambers. The

emission patterns of the four air toxics

were measured by a dynamic chamber

test. An emission model was

developed to interpret both the static

and dynamic chamber data. The model

verified that the measured static

chamber headspace equilibrium

concentration should represent the

maximum air toxics level achievable

by the shower curtain in an enclosed

environment. Analysis of the dynamic

chamber data indicated that the air

toxics emissions were controlled by a

solid-phase diffusion process and

could result in elevated indoor air

toxics concentrations for more than a

month. Source: “Proceedings: 9th

International Conference on Indoor

Air Quality and Climate” Monterey,

California June 30 – July 5, 2002

(EPA Contact: John Chang, 919-541-

3747, chang.john@epa.gov) 

Potential for Reducing Styrene

Exposures from Copied Paper

ThroughUse of Low-Emitting Toners

Tests were conducted using 53-L

chambers to determine styrene

emission rates from freshly copied

paper produced on a si ngle

photocopier, using two toners

manufactured for the copier but having

different styrene contents. Copiedpaper styrene emissions with both

toners could be represented by a power

law or a 3 rd -order decay model (R 2

= 0.94 to 0.99). The two toners

resulted in copied paper having

significantly different styrene

emissions (p<0.01). Unit mass

emissions of styrene (ug/m 2 ) over

1,000 h are predicted to be 9 times

greater from paper with the higheremitting toner. But even copied paper

produced using a still-higher-emitting

toner reported in the literature, is

predicted to produce peak indoor

styrene concentrations in a typical

office only 0.3% of the estimated

minimum concentration of concern to

susceptible sub-populations. Thus, for

the toners studied here, indoor styrene

exposures from copied paper appear

too limited to provide incentive for

switching to the lower-emitting toner.

Source: “Proceedings: 9th

International Conference on Indoor

Air Quality and Climate” Monterey,

California June 30 – July 5, 2002

(EPA Contact: Bruce Henschel, 919-

541-4112, henschel.bruce@epa.gov) 

The Distribution of Chlorpyrofos

Following a Crack and Crevice Type

Application in the U.S. EPA Indoor

Air Quality Test House. A study was

conducted in the U.S. EPA Indoor Air

Quality Research House to determine

the spatial and temporal distribution of

chlorpyrifos following a professional

crack and crevice application in the

kitchen. Following the application,

measurements were made in the

kitchen, den and master bedroom over

21-days. Airborne concentrationswere

collected using both polyurethane

foam (PUF) and a XAD/PUF (OVS)

media. Measured airborne

concentrations were similar for the

two samplers, were higher in the three

rooms following the application,

reached maximal levels 24-h postapplication, and declined steadily over

the 21-day study period. Spatial and

temporal distributions were measured

using 10-cm 2 cotton deposition

coupons. Sections were cut from

existing carpet to determine the total

extractable residues. Chlorpyrifos was

measured from all matrixes in the

kitchen, den and bedroom and shows

the transport of airborne residues from

the point of application to remote

locations in the house. Source:

“Proceedings: 9th International

Conference on Indoor Air Quality and

Climate”Monterey, California June 30

– July 5, 2002 (EPA Contact: Mark

M ason, 919-54 1-4835 ,

mason.mark@epa.gov) 
Inside IAQ, Fall/Winter 2002 Page 10

Impact of an Ozone Generator Air

Cleaner onStyreneConcentrations in

an Indoor Air Quality Research

Chamber W e

investigated the impact of an ozone

generator air cleaner on vapor-phase

styrene concentrations in a full-scale

indoor air quality test chamber. The

time history of the concentrations of

styrene and ozone is well predicted by

a simulation model using the reaction

rate constant for styrene/ozone that

has been determined at atmospheric

pressure and room temperature. In

three tests, the reaction products,

formaldehyde and benzaldehyde, were

produced in ratios of 0.64±0.22 and

0.82±0.19 mole (average ± standard

deviation), respectively, for each mole

of styrene consumed. Two tests were

conducted in near-static- chamber

conditions, and one test was conducted

at 1 air exchange per hour (ACH). The

test results demonstrate that, where

styrene is present, ozone generator air

cleaners increase indoor exposure to

formaldehyde and other oxygenated

organic compounds as well as to ozone

and nitrogen dioxide. Source:

“Proceedings: 9th International

Conference on Indoor Air Quality and

Climate”Monterey, California June 30

– July 5, 2002 (EPA Contact: Mark

Mason, 919-541-4835 ,

mason.mark@epa.gov) 

Improved Test Methods for

Electronic Airt Cleaners The

objective of this project was to

develop a fractional filtration

efficiency test protocol for residential

ESPs that avoids the limitations of the

ASHRAE 52.2 method. Specifically,

the objectives were to a) determine the

change in efficiency that residential

ESPs undergo in real life and b)

develop accelerated laboratory

methods that reasonably reproduce the

real life changes. This work was

conducted as part of the

Environmental Protection Agency’s

(EPA) Environmental Technology

Verification (ETV)program for Indoor

Air Products. Results from the real life

study revealed that the observed

decrease in ESP filtration efficiency

was due to reduced corona discharge

from the ionizing wires, as opposed to

dust collection on the precipitator

plates. Analysis of the wires showed

that they had become coated with a

silicon compound, presumably silicon

dioxide formed by a corona-enhanced

vapor deposition process. A laboratory

method to reproduce and accelerate

the vapor deposition process was

developed. Source: “Proceedings: 9th

International Conference on Indoor

Air Quality and Climate” Monterey,

California June 30 – July 5, 2002

(EPA Contact: Les Sparks, 919-541-

2458, sparks.les@epa.gov) 

Testing Indoor Air Products: One

Approach to Developing Widely

Accepted Protocols RTI is a partner

in the US EPA’s Environmental

Technology Verification (ETV)

Program, with responsibility for

evaluation of products intended to

improve indoor air quality. The

program objective is to further the

development of self-supportingprivate

environmental testing/certification

programs for indoor air products by

convening stakeholder groups and

developing and verifying test

protocols. The protocols have also

been specified in public and private

procurements. Two areas of emphasis

have been low emitting (i.e., low off

gassing) commercial furniture and

general ventilation filters for removal

of aerosol contaminants. These areas

have been reported earlier. A third

area of emphasis currently being

pursued is the evaluation of in-duct

electronic air cleaners. While the

ASHRAE 52.2 is a starting point for

the test protocol, RTI has investigated

conditioning and dust loading issues

specific to electronic air cleaners. A

companion paper at the conference

discusses the laboratory results.

Source : “Proceedings: 9th

International Conference on Indoor

Air Quality and Climate” Monterey,

California June 30 – July 5, 2002

(EPA Contact: Les Sparks, 919-541-

2458, sparks.les@epa.gov) 

A Multipollutant Model for

Estimating the Impact of Pollutants

on Indoor Air Quality Most existing

indoor air quality (IAQ) models are

not well suited for analysis of the

impacts of sources that emit several

pollutants into the indoor environment.

These models are also not well suited

for the analysis of the impacts of

particulate matter (PM) on the indoor

environment because of the need to

include particle size distribution in the

analysis. The IAQ model RISK was

rewritten to allow analysis of multiple

pollutants and PM. The IAQ model

includes several new source emission

models developed from EPA’s

ongoing indoor source research

program. For PM, the model allows

analysis of the effects of: the building

shell on the penetration of outdoor

particles into the indoors, the

deposition of particles to indoor

surfaces, particle removal by air

cleaners, and indoor particle sources.

Model predictions are in good

agreement with the experimental data

from EPA’s IAQ resear ch

house.Source: “Proceedings: 9th

International Conference on Indoor

Air Quality and Climate” Monterey,

California June 30 – July 5, 2002

(EPA Contact: Les Sparks, 919-541-

2458, sparks.les@epa.gov) 
Inside IAQ, Fall/Winter 2002 Page 11

GLOSSARY OF ACRONYMS

ACH-Air Exchanges per Hour

APPCD-Air Pollution Prevention &

Control Division

ASHRAE-American Society of

Heating, Refrigerating, and AirConditioning Engineers

ASTM-American Society for Testing

 and Materials

CFM-Cubic Feet per Minute

COPD-ChronicObstructive Pulmonary

Disease

ELPI-Electrical Low Pressure

Impactor

EPA-Environmental Protection

Agency

ESP-Electrostatic Precipitator

ETV-Environmental Technology

Verification

HAP-Hazardous Air Pollutant

HVAC-Heating, Ventilating, and AirConditioning

IAQ-Indoor Air Quality

IEMB-Indoor Emissions Management

Branch

MEKO-Methyl Ethyl Ketoxime

MIBK-Methyl Isobutyl Ketone

NAAQS-NationalAmbient Air Quality

Standards

NRMRL-National Risk Management

Research Laboratory

NTIS-National Technical

Information Service

PM-Particulate Matter

PM2.5-Particulate Matter < 2.5 um in

aerodynamic diameter

PUF-Polyurethane Foam

QSARs-Quantitative StructureActivity Relationship

RH-Relative Humidity

RTI-Research Triangle Institute

STKi-Simulation Tool Kit 

VOC-Volatile Organic Compound
SYMPOSIUM ANNOUNCEMENT

Indoor Air Quality Problems and Engineering Solutions

The Indoor Air Quality Problems and Engineering Solutions Symposium, an international symposium cosponsored by

EPA’s National Risk Management Research Laboratory and the Air & Waste Management Association, will be held

July 21-23, 2003, 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

Protecting the Indoor Environment from Terrorism

Indoor Air Source Management

Low Emitting/Low Impact Materials Development

(Pollution Prevention)

Biocontaminant Prevention and Control

Indoor Air Cleaning Methods

Asthma and Children’s Health in the Indoor

Environment

Ventilation for Indoor Air Quality

HVAC Systems as Sources of Indoor Air Pollution

Air Duct Cleaning

Particles and Particle Entry into the Indoor

Environment

Indoor Air Quality Modeling

Costs of Managing Indoor Air Quality

Evaluation and Verification of IAQ Alternatives

Exposure in the Indoor Environment

The symposium will consist of one general session so that participants will be able to attend all sessions. A poster

session, continuing education courses, and an exhibition of related products and services are planned. A tour of the

U.S. EPA's new research facilities will be offered. The conference site has convenient access to nearby restaurants,

shopping, and entertainment. A reception is also planned for the first evening.

Send abstracts of 200-300 words by January 10, 2003, to: Jim Jetter, U.S. EPA, Mail Drop E305-03, Research

Triangle Park, NC 27711; telephone (919) 541-4830; fax (919) 541-2157; email jetter.jim@epa.gov. Abstracts

should include paper title, author name(s), address(es), phone number(s), fax number(s), and email address(es).

For further information on the symposium and exhibition, see AWMA's web site at http://www.awma.org/events/,

or contact Denise Stotler at (412) 232-3444, ext. 3111, dstotler@awma.org.

United States

Environmental Protection Agency

National Risk Management Research Laboratory

Indoor Environment Management Branch

Mail Code E305-03

Research Triangle Park, NC 27711

Official Business

Penalty for Private Use

$300

EPA/000/X-00/000, Fall/Winter 2002

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