United States National Exposure

Environmental Protection Research Laboratory

Agency Research Triangle Park NC 27711

Research and Development EPA/600/SR-96/001 March 1996

Evaluation of Dust Samplers for

Bare Floors and Upholstery

 J.W. Roberts, W. Han, and M.G. Ruby

Project Summary

The high volume small surface sampler (HVS3) has been validated for measuring lead, pesticides, PAHs, and

PCBs in dust in carpets. This is described in ASTM method D5438-94.

However, a reliable method is needed

for measuring dust and the pollutants

in dust on bare floors and upholstery

to estimate exposure from such sources. The full report describes tests using the new high volume furniture

sampler (HVFS) to collect dust from

ten used sofas, test pillows with flat

and plush covering, and bare floors. A

high efficiency particle filter was used

after the cyclone in three tests to determine the penetration of the cyclone

by couch dust. Particles above 5 μm

are captured in the cyclone. Less than

0.22% of the dust penetrated the cyclone used on the HVFS. A prototype

High Volume Tripod Sampler (HVTS)

was tested on bare floors and carpets,

as well. The Baltimore R&M Cyclone

Sampler (BRMCS) was also tested.

The HVS3, HVTS, HVFS, and BRMCS

all had similar average efficiencies on

bare floors or surfaces ranging from

84.2 to 86.7%. The HVFS cyclone with

a flexible wand and a notched nozzle

showed an average dust collection efficiency of 88.6 to 90.5% on light and

heavy loading on foam cushions covered with flat and plush coverings. The

HVTS had an average efficiency of 62%

on plush carpet and 64.5% on level

loop carpet on plush and flat upholstery. The BRMCS had a collection efficiency of 44.1% on plush and 61% on

level loop carpet as well as 71.8% and

87.2% on plush and flat upholstery.

Methods for sampling bare floors and

upholstered furniture were developed.

The HVS3 and HVFS provide a reliable

method of sampling bare floors and

upholstered furniture. The BRMCS is a

reliable way to sample bare floors. The

HVTS and BRMCS are lower in cost

than the HVS3 but have limitations for

sampling carpets.

The full report was submitted in fulfillment of Subcontract 46534(g217338-

02)-0003EQ between Battelle Memorial

Inst. and Engineering Plus, Inc. This

report covers the period between January 3, 1993, and Sept. 30, 1993. Work

was completed as of Sept. 30, 1993.

This Project Summary was developed

by EPA’s National Exposure Research

Laboratory, Research Triangle Park, NC,

to announce key findings of the research

project that is fully documented in a

separate report of the same title (see

Project Report ordering information at

the back).

Introduction

House dust is recognized as an important source of potential exposure to allergens, lead, pesticides, and other pollutants

in the home. The dust in a rug or couch

and on a bare floor may also contribute to

personal exposure to airborne particles,

allergen, and other pollutants. The High

Volume Small Surface Sampler (HVS3) is

widely used to collect house dust samples

for chemical analysis. Detailed tests have

shown the HVS3 to be useful in sampling

rugs for lead and semi-volatile organic

compounds, specifically pesticides, poly-
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cyclic aromatic hydrocarbons (PAHs), and

polychlorinated biphenyls (PCBs).

Evaluation of the Need for a

Filter in the Sampling Train for

Upholstery Dust

The HVS3 collects its sample in a cyclone. It has been previously shown that

over 99% of rug dust is collected in the

cyclone. In order to determine the collection efficiency of the cyclone on couch

dust, a particle filter was placed in the

sampling train behind the cyclone for a

series of three tests of dust collection from

upholstered furniture. The average weight

of the dust on the filter was less than

0.22% of the total catch on three tests.

The remaining study was conducted without the filter in the system.

Validation Tests of the HVS3,

HVTS, HVFS, and Baltimore

R&M Cyclone Sampler for

Sampling Bare Floors and

Upholstery

Bare Floors

Based on previous testing, two loadings

of 0.1 and 0.5 g/m2 were selected to represent light and heavy loading conditions

for application of dust to a bare floor for

testing the HVS3. A combined house dust

which had been collected from a number

of Seattle homes, sieved through a 100

mesh screen (< 150 μm), and finally mixed,

was spread on a cleaned section of an

asphalt tile floor and, subsequently, a varnished wood floor. The surface was then

sampled with the HVS3.

A modification of the HVS3, called the

High Volume Tripod Sampler (HVTS), was

designed by Cascade Stack Sampling Systems to minimize air currents next to the

floor. This modification had the same

nozzle and cyclone as the HVS3. This

prototype of a floor sampler suspends the

sampling head from a wheeled tripod and

powers it with a portable vacuum cleaner

that can be slung over the shoulder. A

four horsepower (10.0 amp) Royal Can

VacTM, Model 3004 canister vacuum

cleaner was used to move air through the

HVTS. The Can Vac weighs 9 pounds

and the HVTS weighs 13 pounds.

The average efficiency of the HVTS for

the same light and heavy dust loading

was 84.2 and 85.1%, which on bare floors

is nearly the same as with HVS3 (86.7

and 84.8% respectively). The HVTS was

also tested on carpets, and the results

averaged 62% for plush and 64.5% for

level loop. The carpets were plush and

level loop test carpets meeting the ASTM

method F655-89 standards. The recovery

rate of the HVTS is less than the 67 to

69% recovery rate of the HVS3.

Upholstery Sampling

The HVFS upholstery sampler with a

notched nozzle and flexible wand was designed by CS3. The same Royal Can

VacTM used with the HVTS was used to

move air. This design preserves the essential elements of the HVS3, although it

was necessary to modify the nozzle to

avoid sealing to the fabric being sampled.

Two popular coverings of couch cushions, a flat poly-cotton (53% cotton and

47% polyester) and a velvet (65% cotton

and 35% polyester), were selected for testing. Each cushion was built around a high

density polyurethane foam core. The air

flow through the HVFS was adjusted to

14.4 L/S (30.5 CFM) and the pressure

drop across the nozzle to 10.2 cm (4

inches) water gauge for the flat poly-cotton cushion. The air flow was set at 11.6

L/S (24.5 CFM) and the pressure drop

across the nozzle at 31.8 cm (12.5 inches)

water gauge for the velvet cushion. The

light and heavy surface loadings of 2.5

and 5.6 g/m2 for sampling were selected

on the basis of the loadings found on ten

used sofas. The dust was placed in a

45.7cm x 45.7cm (18"x18") square on the

cushion and embedded with a 34 pound

mallet. The dust collection efficiency of

the HVFS furniture sampler is shown in

Table 1. The average efficiency of dust

collection varied within a range of 87 to

90% for light and heavy loadings on velvet and flat cushions.

Comparative Tests

The Baltimore R&M Cyclone Sampler

(BRMCS) was developed by the Kennedy

Krieger Institute as a sampler for window

sills and similar hard surfaces.

The BRMCS uses the same cyclone as

the HVS3 with a one-inch Tygon© tubing

flexible sampling wand and nozzle. The

nozzle consists of a notched end on the

tube. A Royal Hand VacTM, Model No. 553

(2.0 amp), is used to move air. A paper

bag was used in the Royal Hand VacTM in

the conventional way. The BRMCS was

tested on a bare wood surface, upholstery, and carpets using a modified ASTM

method F609-89. The protocol used for

collecting dust with the BRMCS and the

HVFS were developed for the University

of Rochester lead dust study by the National Center for Lead Safe Housing. The

BRMCS had an average collection efficiency of 84.7% on bare floors, 71.8 and

87.2% on velvet and flat upholstery, as

well as 44.1% on plush and 61% on level

loop carpet.

Sampling Upholstery for Dust,

Lead, Organic, and Allergens

The samples collected from the ten used

sofas were sieved through a 100 mesh

screen and analyzed for total dust, fine

dust, lead, organic, and allergens. The

samples were collected with the HVFS

furniture sampler followed by a Hoover

Brush VacTM, Model No.S1137, with a

power-driven brush in the nozzle. Each

surface that was sampled was passed

over eight times in two directions with

each sampling nozzle. The HVFS collected

72.4 grams and the Hoover Brush VacTM

collected 80.4 grams of total dust from the

sofa cushions. The HVFS and Brush Vac

dust samples from each couch were combined before sieving.

The lead was analyzed using EPA

method SW846 with flame atomic absorption. The couch fine dust lead concentrations ranged from 130 to 380 μg/g with an

average of 229 μg/g.

Dust mite allergens in a combined

sample were measured at 11.1 μg/g for

D. Pteronyssinus (Der p I) and 5.2 μg/g

for D. Farinae (Der f I). Above 10 μg/g is

considered a high exposure for mite allergen. Cat allergen was measured at 37.2

μg/g for F. domesticus (Fel d I). Above 8

μg/g is considered a high exposure for cat

allergen.

Table 1. Efficiency of Dust Samplers

HVS3 HVTS HVFS BRMCS

Bare Floor 85% —87% 84%—85% 84% 85%

Rugs

Plush 69% 62% NA 44%

LL 67% 65% NA 61%

Upholstery

Velvet NA NA 87%—90% 72%

Flat NA NA 89%—91% 87%

LL=Level Loop

NA= Not Applicable
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Results and Discussion

Validated methods of sampling of upholstered furniture and bare floors are necessary to estimate exposure. The three

devices (HVS3, HVTS, and BRMCS)

tested were equally effective (84.2 to

86.7% efficiency) in collecting dust from

bare floors. The HVFS with a cyclone,

wand, and notched nozzle was effective

in sampling upholstery and collected 88.6%

to 90.5% of the dust applied to cushions.

Using the cyclone currently used on the

HVS3 on the other samplers allowed high

air flows that were unaffected by the size

of the sample collected. A large representative sample can usually be collected in

ten minutes. The cyclone allowed less than

0.22% of the total couch dust to pass.

The prototype HVTS and the BRMCS

are both lower in cost than the HVS3 but

have their limitations. The HVTS can be

used effectively on bare floors and hard

surfaces. The HVTS efficiency on carpets

was 5% below that of the HVS3. The

BRMCS is lowest in cost, easier to carry,

and can be used to sample bare surfaces

effectively. Its efficiency on velvet and flat

cotton-poly cushions was 71.8 and 87.2%

respectively. Its efficiency on plush and

level loop carpet was 44.1 and 61% respectively. It has no way to monitor a

drop in air flow due to blinding of the bag,

leaks or motor wear. It will also take longer

to acquire a representative sample from a

carpet.

It is easier to sample for, and may be

more effective to monitor exposure to many

toxic substances, by monitoring house dust

rather than indoor or outdoor air. There is

also a need to continuously improve the

cost effectiveness of such sampling methods. The two lower cost dust sampling

methods evaluated in this study (i.e., the

HVTS and the BRMCS) have potential

and with additional development work can

contribute to effective exposure analysis

on rugs and upholstery as well as bare

surfaces. New procedures are provided in

the full report for sampling bare floors,

hard surfaces, and upholstered furniture.

Conclusions and

Recommendations

This study has demonstrated that the

HVS3 can obtain a reliable sample of dust

from bare floors. The efficiency of all the

samplers on bare floors, rugs, and upholstery are shown in Table 1. Two lower

cost samplers, the prototype HVTS and

BRMCS were also evaluated. The HVS3,

HVTS, and BRMCS all had similar average efficiencies on bare floors or surfaces

ranging from 84.2 to 86.7%. The HVFS

showed an average dust collection efficiency of 88.6 to 90.5% on light and heavy

loading on foam cushions covered with

flat poly-cotton and velvet coverings. The

HVTS had an average efficiency of 62%

on plush carpet and 64.5% on level loop

carpet. The BRMCS had a collection efficiency of 71.8 and 87.2% on velvet and

flat upholstery as well as 44.1% on plush

and 61% on level loop carpet. The efficiency of the HVTS is less than that obtained by the HVS3 but consistent across

carpet types. The BRMCS is not sufficiently consistent with surfaces other than

bare floors and hard surfaces. However,

both the HVTS and BRMCS represent an

important advance and can be expected

to improve with further development. The

method for sampling carpets has been

revised to include bare floors. A new

method for sampling furniture is also included in the appendix of the full report.

The dust loading found in ten used sofas delivered to the Seattle Salvation Army

collection station ranged from 0.95 to 12.27

g/m2 for total dust and 0.11 to 4.9 g/m2 for

fine dust (< 150 micrometers). The lead

concentration in this dust averaged 229

μg/g, with a range of 130 to 380 μg/g. A

combined sample of couch dust contained

a high concentration of 16.3 μg/g and

37.2 μg/g of mite and cat allergen respectively.

There are several important questions

that remain to be answered to assess and

manage the exposure from pollutants in

dust on bare floors, carpets, and upholstery. We recommend

1. Measuring the lead, pesticides,

PAHs, PCBs, and allergen in upholstered furniture and on bare

floors and carpets in a sufficiently

large, representative sample of

homes located in large cities.

2. Documenting the effect of track-in

and dust control as well other cleaning techniques on exposure to the

pollutants from upholstered furniture, carpets, and bare floors.

3. Doing additional development work

to improve the cost-effectiveness

of dust sampling devices.
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United States

Environmental Protection Agency

National Risk Management

Research Laboratory (G-72)

Cincinnati, OH 45268

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

Official Business

Penalty for Private Use

$300

EPA/600/SR-96/001

J.W. Roberts, W. Han, and M.G. Ruby are with Engineering Plus, Inc., Seattle, WA

98112.

Robert G. Lewis is the EPA Project Officer (see below).

The complete report, entitled “Evaluation of Dust Samplers for Bare Floors and

Upholstery,” (Order No. PB96-157474; Cost: $21.50, subject to change) will be

available only from

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at

National Exposure Research Laboratory

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711