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Demonstrating Effectiveness of Passive Radon-Resistant
New Construction
Sharron LaFollette a & Thomas Dickey b
a Department of Health Sciences , Illinois State University , Normal , Illinois , USA
b City of East Moline Health Department , Moline , Illinois , USA
Published online: 27 Dec 2011.
To cite this article: Sharron LaFollette & Thomas Dickey (2001) Demonstrating Effectiveness of Passive Radon-Resistant New
Construction, Journal of the Air & Waste Management Association, 51:1, 102-108, DOI: 10.1080/10473289.2001.10464256
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LaFollette and Dickey
TECHNICAL PAPER
ISSN 1047-3289 J. Air & Waste Manage. Assoc. 51:102-108
Copyright 2001 Air & Waste Management Association
Demonstrating Effectiveness of Passive Radon-Resistant
New Construction
Sharron LaFollette
Department of Health Sciences, Illinois State University, Normal, Illinois
Thomas Dickey
City of East Moline Health Department, Moline, Illinois
ABSTRACT
INTRODUCTION
Fifty percent of homes tested for radon in Rock Island
County, IL, have radon levels above the U.S. Environmen-
tal Protection Agency (EPA) action guideline of 4
picoCuries per liter (pCi/L) of air. Therefore, the county is
classified by the EPA as Zone 1 on the EPA’s Map of Radon
Potential. Radon-resistant new construction (RRNC) strate-
gies for new homes are recommended by the EPA in Zone 1
areas. One city in the county, East Moline, reduced the
cost of building permits for contractors volunteering to
build new homes incorporating modified passive RRNC.
Forty-six of 124 new homes built with passive RRNC in
the city were tested during this study. Only 27 of the
homes tested were below 4-pCi/L, justifying the impor-
tance of testing the system to ensure levels are below the
action guideline. To provide additional support to an ar-
gument in favor of changing city building codes to the
required RRNC, 23 of the homes were also tested with the
systems deactivated. After systems were deactivated, 73%
of the homes had radon levels above the action guide-
line. Four homes were sampled for bioaerosols to evalu-
ate if passive RRNC might impact other indicators of poor
indoor air quality (IAQ). The results of the research will
be discussed here.
The Indoor Radon Abatement Act of 1988 required that
the U.S. Environmental Protection Agency (EPA) provide
guidelines to reduce radon levels in residential buildings.
The early work focused on identifying high-risk areas of
the country using radon data collected from existing struc-
tures and geophysical information. Based on this infor-
mation, the United States has now been divided into three
zones of potential radon risk: from Zone 1, with the high-
est risk potential, to Zone 3, with the lowest risk poten-
tial. Although the EPA continues its risk communication
efforts to reduce radon exposure in existing structures,
the program now includes efforts to build new residential
structures using radon-resistant building designs. In March
of 1994, this resulted in the EPA model standards for ra-
don-resistant new construction (RRNC).1
The city of East Moline, IL, falls within an EPA Zone 1.
A random survey of existing homes in the county (Rock
Island) by the Illinois Department of Nuclear Safety
(IDNS)2 and the EPA3 indicated that >50 and 49%, re-
spectively, of the homes tested had radon levels above the
EPA remediation guideline of 4 picoCuries/liter (pCi/L). In
June 1994, the city health department convinced the
city council to offer a voluntary program for construc-
tion of new, single-family homes using passive RRNC.
The city offered to provide instruction and materials and
to reduce the cost of the building permit as incentives
for contractors to sign up for the program. Through this
program, 11 contractors voluntarily used modified EPA
model standards to incorporate passive RRNC into 124
new homes throughout the city. To prepare the case for
adopting RRNC into city building codes, the health de-
partment conducted several studies to document the ef-
fectiveness of these building techniques in structures
built during the voluntary program. The methodology
and results of this research will be discussed in the fol-
lowing sections.
IMPLICATIONS
Research of radon levels in new homes built in EPA radon
Zone 1 areas indicates that the homes benefit from pas-
sive RRNC. Radon levels in homes with the passive RRNC
system intentionally deactivated were similar to levels in
conventionally built homes and pre-existing homes in the
area. However, not all homes built with passive RRNC
will meet EPA guidelines for radon levels of less than 4
pCi/L air. Testing is necessary to identify homes needing
additional passive or active strategies to further reduce
radon levels.
102 Journal of the Air & Waste Management Association
Volume 51 January 2001

LaFollette and Dickey
METHODS
with the passive systems operational. Canisters were re-
trieved on day 7, sealed, and shipped for laboratory analy-
ses. The systems were then made nonoperational by
placing socket caps over the stack. The socket caps were
equipped with alpha track detectors that were suspended
36 in. down the interior of the stack. On day 14, dupli-
cate charcoal canisters were placed in the same locations
as the initial canisters. The stack pipe alpha track canis-
ters and the charcoal canisters in the indoor living space
were retrieved on day 21, sealed, and shipped for labora-
tory analyses. Operational and nonoperational system
results were compared using regression analysis. The abil-
ity of the stack results to predict either nonoperational or
operational system indoor radon levels was evaluated us-
ing regression analysis.
All homes used in this study were built using modified
EPA standards for RRNC. The homes were built with 4 in.
of aggregate gravel covered with 6-mm-thick polycover
under the slab and a T-pipe penetrating the slab from
which to run a vertical stack through the dwelling exit-
ing out the roof. Most stacks run perpendicular to the
floor, but some are installed with 22 1/2 or 45° offsets to
miss roof trusses and other obstacles. Unfinished base-
ments are not required to have floor penetrations sealed.
Research on the indoor air quality (IAQ) of these single-
family residential structures required the cooperation of
the building contractors or the new owners and residents
of the structure. All homes were tested during the heat-
ing season. The research was conducted through an EPA
Region V assistance grant and research assistance from
the Environmental Health Program at Illinois State Uni-
versity. The research was designed to answer three ques-
tions:
To answer the third question, homes in this study
were tested for bioaerosols, temperature (°F), relative hu-
midity, and CO2 (ppm). The TSI, Inc. Q-TrakIAQ monitor
was used to sample temperature, relative humidity, and
CO2. Levels of bioaerosols were tested inside the stack and
in the lowest level of the home suitable for occupancy
following the seven-plate protocol outlined in PathCon
Laboratories Technical Bulletin 2.4,5 using an Andersen
N6 sampler with a 28.3 L/min flow rate. Collection plate
media and incubation temperatures (°C) were selected to
differentiate between environmental-type (R2Ac agar with
C15H23NO4 at 23.3 °C), human commensal (heart infusion
blood agar at 35 °C), and thermophilic (tryptic soy agar
at 56 °C) bacteria. Samples were collected over a 1 1/2-hr
sampling period. Access to stacks was gained through a
1/4-in. diam hole drilled 3 in. above the floor. Living-space
samples were taken within 3 ft of the stack 12–24 in. from
the floor. Due to the relatively high cost of screening for
bioaerosols, only four homes were screened during this
part of the project. No statistical analyses were performed
on this data due to the small number of homes tested
and the variety of results obtained.
(1) Is there a significant difference in the proportion
of homes above the 4-pCi/L guideline when com-
paring the homes built with the modified RRNC
standards to homes in general in Rock Island
County?
(2) Are the passive systems necessary for these homes
to measure below the EPA 4-pCi/L guideline for
indoor radon?
(3) Can other changes in IAQ be measured as a re-
sult of these systems?
To answer the first question, homes in this study were
tested for indoor radon. Homes were first inspected for
compliance with the modified standards. Homeowners
were advised to maintain closed-building conditions for
the duration of a short-term radon test. Charcoal canis-
ters were placed in the lowest level of the home suitable
for occupancy. Criteria for placement of the canisters fol-
lowed EPA guidelines.4 Duplicate canisters were placed and
retrieved after 7 days. Canisters were sealed and shipped
for laboratory analyses. The proportion of modified homes
with radon levels above 4 pCi/L was compared to the pro-
portion of existing homes in Rock Island County2 using a
standard normal test (Z test).
RESULTS
Radon Testing
Eleven contractors voluntarily used modified EPA model
standards to incorporate passive RRNC into 124 new
homes and two room additions around the city. The city
health department has tested 46 of these homes, includ-
ing 2 room additions, for radon levels within the lowest
level suitable for occupancy while the passive system was
operational (Table 1). Of these, 24 homes had results from
both charcoal canisters below the EPA 4-pCi/L guideline.
One home (house #8) had both samples at or below the
guideline, with the average below the guideline. In one
home (house #15), the average of both canisters was be-
low the guideline. After repair of an obstructed T-pipe,
radon levels in another home (house #10) dropped to
To answer the second question, homes in this study
were checked for the effectiveness of the passive system
in reducing indoor radon. This meant that homes were
tested with the passive system both operational and
nonoperational. Radon levels inside the stacks were also
evaluated. Homes were first inspected for compliance with
the modified standards. Homeowners were advised to
maintain closed-building conditions for the duration of
the tests (21 days). On day 1, duplicate charcoal canisters
were placed in the lowest level of the home suitable for
occupancy using EPA guidelines3 to evaluate radon levels
Volume 51 January 2001
Journal of the Air & Waste Management Association 103

LaFollette and Dickey
below the guideline. One of the room
additions showed radon levels below
the guideline in the living space, but
above the guideline in the existing
basement area (house #39). The other
room addition had levels above the
guideline in both the basement sec-
tion under the new addition and in
the basement area under the exist-
ing structure (house #35). The first-
floor living area of this room
addition was not tested.
Table 1. Testing for indoor radon in new homes and room additions equipped with passive RRNC systems. Measured in
lowest level suitable for occupancy unless stated otherwise.
House No.
Passive System
Average
Comments
1
6.0/6.2
12.9/12.0
5.8/6.2
6.1
12.45
6.0
2
3
4
2.0/2.7
2.35
0.6
5
0.5/0.7
6
5.6/5.6
5.6
7
5.7/6.2
5.95
3.8
8
3.6/4.0
Therefore, of the total number
9
1.3/1.8
1.55
18.9
4.9
of structures tested with the passive
system operational, 27 (59%) showed
an average indoor radon level below
the guideline in the lowest level of
the home suitable for occupancy, and
19 (41%) showed an average indoor
radon level above the guideline. Two
of the homes with basement levels
above the guideline (houses #21 and
#22) had radon levels on the first
floor below the guideline. No struc-
tures had indoor radon levels mea-
suring above 20 pCi/L.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
19.6/18.2
4.9/m.i.
1.4/1.2
16.4 (after floor sealed); 2.8/2.4 (after blockage fixed)
Room addition; crawlspace not tested
1.3
3.3/m.i.
1.1/1.1
3.3
1.1
4.2/3.4
3.8
1.2/1.0
1.1
2.5/2.2
2.35
1.7
1.4/2.0
1.0/1.1
1.05
1.1
1.0/1.2
B 5.0/7.8 F 3.0/3.9
B 5.2/m.i. F 3.0/3.9
6.8/6.4
B 6.4 F 3.45
B 5.2 F 3.45
6.2
5.4 (additional sample taken at later date)
Several of the homes with radon
1.1/1.1
1.1
levels above the 4-pCi/L guideline are
being evaluated for additional pas-
sive methods or corrective measures
to stack installation to reduce levels
to below the guideline. An example
is house #10, which was retested af-
ter the floor was sealed (16.4 pCi/L).
Further investigation identified that
T-pipe placement in a pit below the
gravel rather than within the gravel
caused water and mud to clog the
T-pipe inactivating the stack system.
House #10 was retested after the
blockage was fixed and had duplicate
values of 2.8 and 2.4 pCi/L.
12.8/10.9
3.3/2.5
11.85
2.9
2.7/3.0
2.85
3.1
3.1/3.1
8.5/n.a.
2.1/2.2
8.5
2.15
8.2
8.7/7.7
1.4/1.7
1.55
4.2
4.1/4.3
3.8/n.a.
9.7/10.2
3.8
9.95
Room addition (not evaluated);
tested existing basement;
12.4 (additional sample taken at later date)
36
37
38
39
1.2/1.8
9.0/9.6
1.5
9.3
8.1/8.4
8.25
B 4.8/4.8 LR 2.7/3.7
B 4.8 LR 3.2
Existing basement tested; room addition
w/crawlspace; living room tested,
crawlspace not tested
Owners of 23 of the tested
homes volunteered to participate in
the study in which the passive sys-
tems would be nonoperational in
order to evaluate stack radon lev-
els and ability of the passive sys-
tems (Table 2) to reduce radon
levels in these particular homes.
Twenty-two of the homes were
tested under operational and
nonoperational conditions. With
40
41
42
43
44
45
46
1.4/2.0
12.0/12.9
1.3/1.7
5.6/4.1
1.4/1.0
0.8/0.2
8.0/n.a.
1.7
12.45
1.5
4.85
1.2
0.5
8.0
Note: B = basement; F = first floor; LR = living room; m.i. = missing information, no lab analysis; and n.a. = not available.
104 Journal of the Air & Waste Management Association
Volume 51 January 2001

LaFollette and Dickey
Table 2. Testing for indoor radon in new homes equipped with passive RRNC systems (operational and nonoperational).
the systems nonoperational, 16
(73%) of these homes had aver-
age radon levels greater than the
4-pCi/L guideline, and 6 (27%)
were below the guideline. Stud-
ies by the EPA and IDNS indi-
cate 50% of the homes built
without RRNC in Rock Island
County have levels above the
guideline.2,3 A standard normal
test (Z test) indicated that the
proportion of homes built to the
modified RRNC standards with
radon levels above the 4-pCi/L
guideline (with the system
nonoperational) was signifi-
cantly higher than the propor-
tion of homes in general in Rock
Island County with radon lev-
els above the 4-pCi/L guideline
(Z = 4.17; P < 0.01). Two homes
with nonoperational systems
had average radon levels greater
than 20 pCi/L. A paired t test
analysis indicated a significant
difference in the mean radon
levels when comparing opera-
tional and nonoperational sys-
tems in homes built to the
modified RRNC standards (T =
House No.
Operational
Nonoperational
Inside Stack
Comments
1
6.0/6.2
12.9/12.0
5.8/6.2
6.8/7.6
13.4/11.9
26.4/29.7
2.6/2.7
30.2
32.9
302.4
53.8
209.8
7.4
2
3
4
2.0/2.7
5
0.5/0.7
10.8/11.4
7.8/8.6
6
5.5/5.6
7
5.7/6.2
4.6/5.4
10.6
40.3
205.8
<2
8
3.6/4.0
3.5/3.2
9
1.3/1.8
15.3/13.4
10.3/10
10
19.6/18.2
Repaired
B 2.8/2.4 F 1.6/m.i.
4.9/m.i.
16.4 (after floor sealed);
T-pipe blocked
11
12
13
14
15
16
17
18
19
20
21
22
23
10.9/8.9
1.2/2.2
581.1
1.4/1.2
n.a.
3.3/m.i.
4.9/4.5
186.3
1.1/1.1
10.1/9.0
90.1
4.2/3.4
7.7/7.9
143.3
1.2/1.0
2.8/2.5
89.6
2.5/2.2
7.7/8.5
246.8
1.4/2.0
n.a.
19.2
1.0/1.1
1.6/1.5
208.1
1.0/1.2
2.1/2.3
615.4
B 5.0/7.8 F 3.0/3.9
B 5.2/m.i. F 3.0/3.9
6.8/6.4/5.4
B 11.2/16.8 F 9.3/12.0
B 27.5/27.8 F n.a.
n.a.
85.4 @ 12 in. 91.9 @ 36 in.
n.a.
T-pipe blocked
716.3
Additional sample
Note: B = basement; F = first floor; m.i. = missing information, no lab analysis; and n.a. = not available.
2.86; DF = 18; P = 0.01). Twenty-one of the homes were
tested for radon levels inside the stack (house #10 stack
results were omitted in statistical analyses since the stack
was blocked). Regression analyses showed that stack ra-
don levels could not be used to predict indoor radon lev-
els with systems either operational or nonoperational.
winter clothing.6 Levels of CO2 (970–1240 ppm) in all
homes were near or above the 1000-ppm ceiling level for
general comfort.7 Relative humidity (37.4–68.6%) was at
or below outdoor levels in all of the homes. Only one
home (house #5) had a relative humidity level above the
recommended range of 30–60%.6
Bioaerosol samples were evaluated for total (on Rose
Bengal agar) fungi and bacterial colony-forming units per
cubic meter of air (CFU/m3) and fungi and bacterial gen-
era prevalence (see Table 3). Total fungi CFU/m3 were
greater inside the stack than in basement air in three of
the four homes. Total bacterial CFU/m3 for environmen-
tal-type bacteria were higher in basement air for all but
house #17. Total bacterial CFU/m3 for human commen-
sal bacteria were higher in two of the homes (houses #5
and #17) and the same in the other two homes (houses
#10 and #13). Total bacterial CFU/m3 for thermophilic
bacteria were below detection limits of the analyses (<12
CFU/m3).
IAQ Analyses
The owners of four homes (houses #5, #10, #13, and #17)
volunteered to participate in evaluating other IAQ param-
eters of their homes under operational passive RRNC con-
ditions (Table 3). Samples were collected on an overcast
December day with the outdoor temperature at 36.9 °F,
68.7% relative humidity, and 607-ppm CO2 at 11:00 a.m.
The basements (one finished, three unfinished) of these
homes were tested for temperature, relative humidity, CO2,
and bioaerosols. The stack interiors were sampled for
bioaerosols. The CO2 level and temperature in all of the
homes were above outdoor levels. The temperatures (65.8–
71 °F) were all above the minimum comfort temperature
(65 °F) for sedentary occupancy of more than an hour
and at or below the optimum operative temperature (71 °F)
recommended for people wearing typical indoor
In general, where fungi and bacteria were identified,
the profile of genera was different inside the stack as com-
pared with basement air (Tables 4 and 5). Where fungi
were identified both inside the stack and in basement air,
Volume 51 January 2001
Journal of the Air & Waste Management Association 105

LaFollette and Dickey
Table 3. Bioaerosol and environmental data collected from four East Moline houses on December 10, 1997, during an overcast day at an outside temperature of 36.9 °F, relative
humidity 68.7%, and 607-ppm CO2 (measured at 11:00 a.m.).
House 5
House 10
Basement
House 13
House 17
Basement
Vent
Basement
Vent
Vent
Basement
Vent
Room Temp. (°F)
Relative Humidity (%)
CO2 (ppm)
71
68.7
970
<12
59
66.8
37.4
1240
<12
106
24
69.1
43
65.8
37.4
1088
200
24
1305
141
94
Fungia (CFU/m3)
Bacteriaa (CFU/m3)
Bacteriaa (CFU/m3)
Bacteriaa (CFU/m3)
71
12
59
82
766
236
<12
<12
<12
<12
<12
<12
<12
<12
118
<12
24
<12
<12
47
<12
<12
<12
aBased on Andersen sampler flow rate of 28.3 L/min for 3-min sampling time.
the genera profile was different except for house-specific
similarities in the presence of Aspergillus versicolor and
penicillium in two of the homes (houses #13 and #17).
Where environmental-type bacteria were identified both
inside the stack and in basement air, the genera profile
was different except for flavobacterium-like bacteria in
house #10. Where human commensal bacteria were iden-
tified both inside the stack and in basement air, the gen-
era profile was different except for bacillus in house #10.
soil depression systems in the East Moline study. Most of
the Colorado homes tapped into exterior drainage sys-
tems as compared with the underslab systems built in East
Moline. The Colorado homes were tested on the lowest
and main levels for 91–120 days using alpha track detec-
tors. All but two of the homes exhibited radon levels of less
than 4 pCi/L. Lower-level readings averaged 1.58 pCi/L, while
the main level readings averaged 1.11 pCi/L. The passive
soil depression systems in East Moline (46 homes) exhib-
ited average lower-level readings of 4.3 pCi/L. Active soil
depression systems are more effective than passive sys-
tems in reducing indoor radon levels and may be retrofit-
ted into some of the East Moline homes currently above
the EPA action guideline for radon.
Two homes in northern Virginia (VA1 and VA2) and
two homes in Allentown, PA (PA1 and PA2), constructed
with subslab depressurization systems were studied in
1989 by Brennan et al.9 Three of the four homes in the
Brennan study were unoccupied, whereas all homes were
occupied in the East Moline study. Use of the home by
occupants may affect radon levels.10 Subslab radon grab
samples were taken in all four homes and averaged less
than 100 pCi/L.
The Brennan study compared indoor radon levels in
two of the homes (PA1 and PA2) with the systems under
passive and active modes. PA1 averaged 1.1 ± 0.2 pCi/L of
radon in the active mode and 8.2 ± 2.4 pCi/L in the pas-
sive mode. PA2 averaged 0.4 ± 0.3 pCi/L of radon in the
active mode and 3.5 ± 3.4 pCi/L in the passive mode. VA1
interior radon levels averaged 1.3 pCi/L under the pas-
sive mode and were not tested in the active mode. VA2
was excluded from this part of the study because the au-
thors felt that the radon level in the subslab space was
too low to provide meaningful interior comparisons. The
East Moline in-stack radon levels measured over 7 days in
19 homes (36 in. from top of stack) averaged 204 pCi/L.
The indoor radon levels for passive systems in the East
Moline study averaged 4.3 pCi/L.
DISCUSSION
RRNC methods used voluntarily by 11 contractors in the
city of East Moline were effective in lowering indoor ra-
don levels below the levels that would have been present
had the same house been built without the system. Sev-
enty-three percent of the homes tested in this study (16/22)
had levels greater than 4 pCi/L when the passive system
was nonoperational. Forty-one percent of the homes tested
in this study (19/46) had levels above 4 pCi/L when the
passive system was operational. These data can be com-
pared with studies of existing homes in Rock Island
County that indicate greater than 50% of the homes have
radon levels above 4 pCi/L.2,3 The results of this small-
scale research project were instrumental in convincing
the city council to adopt the modified EPA RRNC model
standards into city building codes. The city is currently
evaluating additional passive methods by which to de-
crease indoor radon levels in homes not meeting the EPA
action guidelines for radon. If necessary, the systems can
be converted to active systems by placing in-stack exhaust
fans at the attic levels of these homes to reduce indoor
radon levels to below the guideline.
No large-scale studies evaluating the effectiveness of
RRNC have been identified. Kladder and Jelinek8 studied
15 of 44 homes built with RRNC in the Front Range of
the Rocky Mountains (El Paso County) within Colorado
during the summer of 1992. All the Colorado homes had
active soil depression systems as compared with passive
106 Journal of the Air & Waste Management Association
Volume 51 January 2001

LaFollette and Dickey
Table 4. Fungi and bacterial genera prevalence collected from East Moline houses #5 and #10 on December 10, 1997, during an overcast day at an outside temperature of 36.9 °F,
relative humidity 68.7%, and 607-ppm CO2 (measured at 11:00 a.m.).
House 5
House 10
Vent
Basement
Vent
Basement
Fungia
Mycelia Sterilia (3/6)
Penicillium (2/6)
Penicillium (1/1)
Monocillium-like (1/6)
ET Bacteriab
HC Bacteriac
Flavobacterium-like (4/5)
Corynebacterium-like (1/5)
Flavobacterium (6/10)
Gram negative rod (4/5)
Flavobacterium-like (1/5)
Bacillus (1/2)
Flavobacterium-like (5/9)
Aeromonas-like (4/9)
Bacillus (2/2)
Staphylococcus, not aureus (4/10)
Micrococcus luteus (1/2)
Note: ET = environmental-type bacteria and HC = human commensal; aColony-forming units on Rose Bengal agar listed in descending order of occurrence (taxon count/total count);
bColony-forming units on R2Ac agar listed in descending order of occurrence (taxon count/total count). R2Ac agar is designed to culture environmental bacteria; however, this medium
c
may also support growth of human commensal bacteria; Colony-forming units on blood agar listed in descending order of occurrence (taxon count/total count). Blood agar is
designed to culture human-associated bacteria; however, this medium may also support the growth of environmental bacteria.
Saum and Osborne11 studied 16 homes in Maryland
and Pennsylvania built with RRNC methods. All homes
were examined with the T-pipe capped prior to stack in-
stallation. Indoor radon levels ranged from 4 to 20 pCi/L
prior to stack installation. Half of the homes in the Saum
study were evaluated in order to compare the performance
of the system in the passive mode and in the active mode.
Only the data from two of these homes were presented.
Both homes were studied during winter and summer
months. Home #1 had an average passive mode performance
of 2.9 pCi/L in the summer and 0.7 pCi/L in the winter,
and an average nonoperational mode performance of 19.9
pCi/L in the summer and 2.4 pCi/L in the winter. Home #2
had an average passive mode performance of 7.5 pCi/L in
the summer and 3.7 pCi/L in the winter, and an average
nonoperational mode performance of 29.0 pCi/L in the
summer and 0.3 pCi/L in the winter. The levels in the
East Moline study ranged from 1.4 to 29.7 with the pas-
sive system nonoperational. The levels in the East Moline
study ranged from 0.2 to 12.9 pCi/L with the passive
systems operational. All the homes in the East Moline
study were tested during the winter months.
Table 5. Fungi and bacterial genera prevalence collected from East Moline houses #13 and #17 on December 10, 1997, during an overcast day at an outside temperature of 36.9 °F,
relative humidity 68.7%, and 607-ppm CO2 (measured at 11:00 a.m.).
House 13
House 17
Vent
Basement
Vent
Basement
Fungia
Monocillium-like (4/7)
Aspergillus versicolor (2/7)
Fusidium (1/7)
Aspergillus, not fumigatus (7/12)
Cladosporium (2/12)
Penicillium 1 (19/65)
Penicillium 2 (18/65)
Tritirachium (8/65)
Aspergillus versicolor (13/17)
Fusidium (1/17)
Aspergillus versicolor (1/12)
Fusidium (1/12)
Geotrichum (1/17)
Penicillium 3 (7/65)
Aspergillus versicolor (4/65)
Monocillium-like (3/65)
Cladosporium (2/65)
Mycelia Sterilia (2/65)
Penicillium 4 (1/65)
Penicillium 5 (1/65)
Sphingomonas (13/20)
Bacillus (7/20)
Oidiodendron (1/17)
Penicillium (1/17)
Penicillium (1/12)
ET Bacteriab
HC Bacteriac
Micrococcus varians (5/8)
Flavobacterium (3/8)
Flavobacterium-like (2/2)
Curtobacterium-like (2/4)
Staphylococcus, not aureus (2/4)
Note: ET = environmental-type bacteria and HC = human commensal; aColony-forming units on Rose Bengal agar listed in descending order of occurrence (taxon count/total count);
bColony-forming units on R2Ac agar listed in descending order of occurrence (taxon count/total count). R2Ac agar is designed to culture environmental bacteria; however, this medium
c
may also support growth of human commensal bacteria; Colony-forming units on blood agar listed in descending order of occurrence (taxon count/total count). Blood agar is
designed to culture human-associated bacteria; however, this medium may also support the growth of environmental bacteria.
Volume 51 January 2001
Journal of the Air & Waste Management Association 107

LaFollette and Dickey
Prior to adopting the modified EPA model standards
as part of the East Moline building codes, the city health
department wanted to determine if stack radon levels
could be used to predict the need for RRNC. Data from
this limited study indicate that stack levels do not predict
indoor radon level with the system either nonoperational
or operational. No other studies could be located that at-
tempt to predict indoor radon levels from stack or subslab
radon levels. Soil radon levels have been found to give
only limited information about expected indoor radon
concentration and are unreliable in predicting seasonal
and local variations.12
the voluntary phase of the RRNC in the city of East Moline.
We would also like to thank Christopher Janicak for his
assistance with the statistics; Timothy Kelley for his assis-
tance with bioaerosol monitoring and report review; and
William Martz and Marilyn Morrow for their editorial
comments.
REFERENCES
1. Model Standards and Techniques for Control of Radon in New Residential
Buildings; EPA 402-R-94-009; U.S. Environmental Protection Agency,
Office of Air and Radiation, U.S. Government Printing Office: Wash-
ington, DC, 1994.
2. Radon Illinois: A Status Report; Illinois Department of Nuclear Safety,
State of Illinois: Springfield, IL, 1992 Update; 2189/Reprint-100-6/
97.
No other studies could be located that examine the
impact of RRNC methods on general air quality of the
new homes. The four homes for the East Moline study
represented residency time of less than 2 years in all
homes. General IAQ was consistent with homes closed
up during a heating season (temperature, humidity, and
CO2). The National Institute for Occupational Safety and
Health (NIOSH) has previously suggested a level of viable
microorganisms in excess of 1000 CFU/m3 indicates that
the indoor environment may be in need of further inves-
tigation and possible improvement.13
The total numbers of fungi and bacteria found in the
basement air of the East Moline homes ranged from 130
to 506 CFU/m3, well under the NIOSH level of concern.
Stack levels ranged from 71 to 1084 CFU/m3. Fungi levels
were higher in the stack than in the indoor environment
for three of the four homes. Bacteria levels were higher in
the indoor air than in the stack for three of the four homes.
Fungi and bacteria have been isolated in a variety of
sources and reservoirs both in buildings and in the envi-
ronment.14 The fungi and bacteria identified in the East
Moline homes and stacks are consistent with fungi and
bacteria identified in other studies. The genera profile was
generally different between stack samples and basement
air samples. Data collected from the four East Moline
homes were inadequate to determine if the passive sys-
tems improved overall IAQ in these homes. No further
IAQ studies are planned. The city of East Moline will con-
tinue to work with homeowners and enhancement meth-
ods (e.g., sealing slab-wall interface in basements, sealing
floor penetrations, insulating the portion of the stack in
the attic, wind turbine cap on stack, etc.) to improve the
effectiveness of RRNC in all homes built during the vol-
untary stage of the program. The city will also offer
postconstruction radon testing to all homeowners want-
ing to evaluate radon levels in their new homes since the
adoption of the RRNC building code.
3. EPA’s Map of Radon Zones: Illinois; EPA 402-R-93-033; U.S. Environ-
mental Protection Agency, Office of Air and Radiation, U.S. Govern-
ment Printing Office: Washington, DC, 1993.
4. Indoor Radon and Radon Decay Product Measurement Device Protocols;
EPA 402-R-92-004; U.S. Environmental Protection Agency, Office of
Air and Radiation, U.S. Government Printing Office: Washington,
DC, 1992.
5. Morris, G.K.; Shelton, B.G. Technical Bulletin 2.4: A Suggested Air Sam-
pling Strategy for Microorganisms in Office Settings; PathCon Laborato-
ries: Norcross, GA, 1997.
6. ASHRAE Standard: Thermal Environmental Conditions for Human Occu-
pancy; ANSI/ASHRAE 55-1992; American Society of Heating, Refrig-
erating and Air-Conditioning Engineers: Atlanta, GA, 1992.
7. ASHRAE Standard: Ventilation for Acceptable Indoor Air Quality; ANSI/
ASHRAE 62-1989; American Society of Heating, Refrigerating and Air-
Conditioning Engineers: Atlanta, GA, 1989.
8. Kladder, D.L.; Jelinek, S.R. Rocky Mountain Region Private Mitigation
Systems Durability Study (New Construction); USEPA-ORD Work Assign-
ment No. 3-10 under Contract No. 68-DO-0097; S. Cohen and Asso-
ciates: McLean, VA, 1993.
9. Brennan, T.; Clarkin, M.; Osborne, M.C.; Brodhead, B. Evaluation of
Radon Resistant New Construction Techniques; Paper provided by U.S.
Environmental Protection Agency, Office of Air and Radiation; un-
published work, not dated.
10. Cohen, B.L.; Gromicko, N. Variation of Radon Levels in U.S. Homes
with Various Factors; J. Air Pollut. Control Assoc. 1988, 38 (2), 129-
134.
11. Saum, D.W.; Osborne, M.C. Radon Mitigation Performance of Passive
Stacks in Residential New Construction; Paper provided by U.S. Envi-
ronmental Protection Agency, Office of Air and Radiation; unpub-
lished work, not dated.
12. Ennemose, O.; Giacomuzzi, S.M.G.; Brunner, P.; Schneider, P.; Stingl,
V.; Purtscheller, F.; Ambach, W. Radon Measurements in Soil To Pre-
dict Indoor Radon Concentrations in New Buildings in an Area with
Unusually High Radon Levels; Sci. Total Environ. 1995, 162, 209-213.
13. Morey, P.R.; Hodgson, M.J.; Sorenson, W.G.; Kullman, G.J.; Rhodes,
W.W.; Visvesvara, G.S. Environmental Studies in Moldy Office Build-
ings: Biological Agents, Sources and Preventive Measures; Ann. ACGIH
1984, 10, 21-35.
14. Steizenbach, L.D. Introduction to Aerobiology. In Manual of Environ-
mental Microbiology; Hurst, C.J., Knudsen, G.R., McInerney, M.J.,
Walter, M.V., Eds.; ASM: Washington, DC, 1997; pp 619-628.
About the Authors
Sharron LaFollette, Ph.D., is director of the Environmental
Health Program, Department of Health Sciences, Illinois
State University, Campus Box 5220, Normal, IL 61790. Tho-
mas Dickey, R.E.H.S., is health inspector, City of East Moline
Health Department, 912 Sixteenth Ave., East Moline, IL
61244.
ACKNOWLEDGMENTS
The authors would like to thank the EPA Region V office
for the Assistance Grant for this study and for promoting
108 Journal of the Air & Waste Management Association
Volume 51 January 2001