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HEALTH CONSULTATION

Indoor Air Quality Evaluation

PHILIP SERVICES CORPORATION
(a/k/a BURLINGTON ENVIRONMENTAL INCORPORATED GEORGETOWN FACILITY)
SEATTLE, KING COUNTY, WASHINGTON


APPENDIX A: EVALUATION OF INDOOR AIR STUDIES

Four environmental studies were conducted between October 1999 and March 2001 to evaluate whether contaminants found in shallow groundwater located west of the PSC facility were migrating into indoor air at homes and businesses above levels of health concern. Each study was evaluated to determine if the data was adequate for determining potential health effects and establishing a link between indoor air contaminants and the contaminated groundwater. The results of the evaluation for each study are presented below:

PSC, Soil Gas and Soil Study, October 1999

The October 1999, PSC study was conducted to determine whether groundwater contaminants had volatilized into the overlying soil in the vicinity of three residences along the west side of Denver Avenue South. VOC concentrations in groundwater near these homes were among the highest detected anywhere west of Denver Avenue South. Soil samples were also collected to determine whether contaminated soil gas was affecting soils as the gas migrated toward the ground surface (Personal communication with Ed Jones, Ecology, October 24, 2002). Two of the homes are underlain by basements (Residence 1 and Residence 2); the third home has an unknown foundation type (Residence 0). Soil and soil gas samples were collected from zero to four feet below ground surface (bgs) near the three homes to support the study (Figure 2).8

Shallow soils (zero to four feet below ground surface (bgs) were collected in the vicinity of the three homes and were analyzed for volatile organic compounds (VOCs) using EPA Method 8260, a standard VOC analytical method. No VOCs were detected in these soil samples except for methylene chloride, which was attributed to laboratory contamination.8

Soil gas samples were also collected by PSC during this study. The samples were collected over a 20-minute period from zero to four feet bgs along the city right-of-way, some distance from the homes and above the base of the basement using unsealed soil gas probes fitted with 6-liter (6L) Summa canisters prepared under negative pressure and equipped with flow restrictors.8 However, the unsealed soil gas probes, which would allow ambient air to migrate down along the probe, and shallow sampling above the bottom of the basement where contaminants tend to pool and concentrate, likely resulted in samples that underestimated soil gas concentrations.

PSC Indoor Air, Groundwater, and Soil Gas Study August 2000

PSC conducted another study in August 2000 so it could evaluate whether VOCs found in groundwater were entering homes and if so, whether this was occurring at levels of health concern. Indoor air samples were collected at two of the three residences: (Residence 1 and Residence 2) (Figure 2). PSC also collected groundwater, soil gas, and ambient air samples during this study to help determine whether contaminants detected in indoor air were associated with groundwater or some other source such as outdoor air, building materials and/or household products.9

To prepare for the indoor air sampling PSC asked residents to leave their homes. The homes were then screened using a photo ionization detector (PID) to identify potential indoor sources of VOCs, which were to be removed if the sources could potentially affect the indoor air sampling results. Only one item was reportedly removed from Residence 1. After the screening was completed, windows and doors were opened and approximately five volumes of air were evacuated from the basements, where samples were to be collected, by running a box fan to flush stagnant air from the homes. After the air was removed, the windows and doors were closed and the air was allowed to equilibrate for approximately 24-hours prior to sampling.9

Three samples were collected in the basement apartment at Residence 1 - two on top of the bed and one in a sitting area. One sample was collected on top of the bed located in the basement bedroom at Residence 2. The samples were collected over a 24-hour period at each home using 6L Summa canisters prepared under negative pressure and equipped with flow regulators. Residents returned to their homes at the end of the sampling, approximately 72 hours after sampling preparation began. The samples were analyzed using a modified version of EPA Method TO-14 in the selected ion mode (SIM) method to achieve lower detection limits for chemicals such as vinyl chloride that are a significant health concern.9

Sampling Protocol Evaluation

The selection of indoor air sample locations and sampling methods appears adequate for assessing indoor air quality at these homes. Only minor analytical differences were noted among the three samples collected in the basement apartment at Residence 1. It is uncertain whether PSC approach for evacuating indoor air and then allowing a 24-hour equilibration period prior to sampling significantly influenced the indoor air results. However, when the results are compared to the DOH sampling results obtained one week later, only relatively minor differences in contaminant concentrations are observed. Consequently, it appears that this approach did not negatively affect the results. Table A-1 provides the maximum indoor air contaminant concentration detected by PSC at Residence 1 and Residence 2. Chemicals reported as nondetects were assigned a value of one-half of the practical quantitation limit (PQL).

Two ambient air samples were collected during the study. One sample (Ambient 1) was a composite sample, which consisted of grab samples of the air coming into Residence 2 collected every 30 minutes for approximately two hours during the air evacuation conducted 24-hours prior to the indoor air sampling. The second ambient air sample (Ambient 2) was collected north of the two homes in the city right-of-way along Denver Avenue S. using a 6-liter (6L) Summa canister prepared under negative pressure and equipped with a flow regulator. Ambient 2 was collected during the same 24-hour period as the indoor air samples and was used during the health consultation to represent background ambient air concentrations.9 The Ambient 2 results are included in Table A-1.6

Soil gas samples were collected at a number of locations during the study. All the soil gas samples were collected over a 24-hour period using 6L Summa canisters prepared under negative pressure and equipped with flow regulators. The soil gas samples were analyzed using a modified version of EPA Method TO-14 (SIM ). Some passive soil gas samples were also collected and analyzed using EPA TO -1.9

A soil gas sample was collected during the same period as the indoor air sampling from a drive point installed 1 to 2 feet through the basement floor at Residence 2 to evaluate soil gas concentrations directly below the building. A single angled drive point was also installed below Residence 2. PSC also installed and sampled two angled drive points 0.5 to 2 feet below the basement at Residence 1. The angled drive points were sampled a few days after the indoor air sampling. To evaluate the differences between soil gas levels below the homes and those encountered in close proximity to the homes, PSC installed five drive points in the city right-of-way at approximately the same depth as the drive points installed below the basement floors. Only the drive point installed directly below the basement floor at Residence 2 had an external seal to prevent the migration of air along the outside of the drive point during sampling.9 Consequently, the contaminant levels in the soil gas may be underestimated.

Eleven groundwater samples were collected as part of this study to try to correlate the soil gas and indoor air sampling results with the chemicals found in groundwater. Three groundwater samples were collected from the drive points installed for the soil gas sampling below Residence 1, Residence 2, and along Denver Avenue South. These drive points were pushed until they encountered groundwater. Three additional drive points were installed into the shallow groundwater aquifer along Denver Avenue South. The wells were purged and sampled using a peristaltic pump and were analyzed for VOCs using EPA Method 8260. A peristaltic pump, however, can cause sample aeration and a resulting loss of VOCs if samples are not properly collected.9 It is assumed that the samples were collected properly. However, if sampling resulted in significant aeration, groundwater contaminant concentrations may be underestimated.

To establish a correlation between chemicals detected in groundwater and those detected in soil gas and indoor air, groundwater samples should be collected at the water table. The groundwater samples collected by PSC, however, were collected from one to two feet below the top of the water table.9 Since little rainfall occurs during the summer months that could dilute the groundwater at the water table, sampling a few feet below the top of the water table should not result in significantly different concentrations then would be found at the water table.

Data Evaluation

The indoor air sampling results from the August 2000 sampling round were initially compared to health comparison values to begin identifying chemicals of potential health concern (COPC). The health comparison values used during the health consultation are listed in Tables A-1; general information about the health comparison values are discussed in Appendix B.

COPC, however, do not necessarily represent a public health hazard but indicate the need for further evaluation. All the chemical results that exceeded health comparison values were then compared to the 24-hour ambient air sample results obtained by PSC (Table A-1), which are similar to outdoor air literature values. Chemicals exceeding health comparison values and the ambient air results were carried forward as COPCs and are shown as bolded, shaded values in Table A-1.

Ten of the 29 chemicals tested in indoor air exceeded conservative health comparison values and ambient air concentrations. Four of the ten chemicals (1,1 dichloroethene; 1,2-dichloroethane; chloroform; and vinyl chloride) were detected in both soil gas and groundwater samples collected by PSC during the August sampling, which suggests that contaminated groundwater may be a source of some of these indoor air contaminants. Methylene chloride, carbon tetrachloride, and ethylbenzene were only detected in soil gas;1,1,2-trichloroethane was only detected in groundwater. The remaining chemicals (1,1,2,2,-tetrachloroethane and 1,2-dichloropropane) were not detected in either groundwater or soil gas, which suggests a source other than contaminated groundwater exists for these chemicals. 6 However, this conclusion could not be confirmed using the soil gas and groundwater data because of potential problems identified with the methods used to collect these samples.

Review of the historic groundwater data for the site (April 1999 - May 2000) presented in PSC draft human health risk assessment (HHRA) indicates that methylene chloride has been detected in over a quarter of the groundwater samples; 1,2-dichloropropane was detected in about a fifth of the groundwater samples; and ethylbenzene was detected in about half of the groundwater samples. Only one groundwater sample contained detectable levels of carbon tetrachloride and no 1,1,2,2-tetrachloroethane was detected in any groundwater sample. However, it appears that the detection limits for carbon tetrachloride and 1,1,2,2-tetrachloroethane were periodically elevated.5 As a result, contaminated groundwater could be a source of the carbon tetrachloride and 1,1,2,2-tetrachloroethane detected in indoor air.

The ten chemicals were retained as COPC and further evaluated. The discussion section of the health consultation summarizes this additional evaluation.

DOH/EPA Indoor Air Study, August 2000

Approximately one week after the PSC August 2000 sampling, DOH and EPA collected indoor air samples at the same two homes (Residence 1 and Residence 2) as well as at an additional home (Residence 3) and two businesses (Business 1 and Business 2) to evaluate whether VOCs found in groundwater were entering homes and if so, whether this was occurring at levels of health concern.10 No screening level monitoring (e.g., PID) was conducted prior the sampling to determine if indoor sources were producing VOCs that could affect indoor air quality at the selected homes and businesses. In addition, no indoor air was evacuated prior to sampling as was conducted by PSC a week earlier and residents and workers were allowed to conduct normal daily activities during the sampling event.

DOH sampled three homes and one business - Residence 1 (basement living room, canister on a table approximately 2 feet above the floor); Residence 2 (basement, canister placed on the floor); Residence 3 (basement, canister placed on the floor) and Business 1 (canister placed on the floor near a sump) (Figure 2). DOH used the same type of sampling equipment as PSC when collecting the indoor air samples- 6L Summa canisters prepared under negative pressure and equipped with flow regulators. All the samples were analyzed using EPA Method TO-15 in the standard scan mode.10

EPA used 6L cylindrical canisters that pumped air into the samplers at a metered rate. These type of canisters are used by Ecology to evaluate ambient air quality [Personal communication, Ed Jones, WA Department of Ecology, July 18, 2002]. Although these canisters are different than the ones used by DOH and Philip, it is unlikely that their use would have affected the sample quality. EPA collected indoor air samples at Business 2 (warehouse, canister placed 3 feet above the floor, near a floor drain) as well as sample on the first floor of Residence 2 (approximately 4 feet above the floor). EPA also collected an ambient sample from the backyard of Residence 3 (3 feet above the ground surface, approximately 30 feet from Maynard Avenue South and 20 feet south of the residence (Figure 2). The EPA samples were analyzed using EPA Method TO-14. However, typical quality assurance data were not available to evaluate the accuracy of the analytical results results.(Personal communication with Ed Jones, Ecology, June 18, 2002).

Sampling Protocol Evaluation

Although DOH did not evacuate air from the homes prior to the indoor air sampling as was conducted by PSC a week earlier, the results obtained by DOH are similar to the results obtained by PSC. The results obtained by EPA, however, were significantly higher for some chemicals than the results obtained by either DOH or PSC. Because of the uncertainty about data quality and the lack of split samples at the locations where DOH and PSC sampled, the EPA data were not used during this health consultation. The indoor air data results, however, are provided in Appendix C, Table C-1.

Data Evaluation

Table A-2 provides a summary of the indoor air data results obtained at the three homes and two businesses sampled by DOH. The ambient air results obtained by PSC the previous week were assumed to be similar to background concentrations during the DOH sampling and were used during the data evaluation. The four chemicals detected by PSC a week earlier in indoor air, soil gas, and groundwater ( 1,1 dichloroethene; 1,2-dichloroethane; chloroform; and vinyl chloride) along with methylene chloride, tetrachloroethene; and ethylbenzene; and toluene were detected above health comparison value and ambient air levels during the DOH sampling in at least one of the residences and businesses. These five chemicals were also detected in groundwater and soil gas.

Other chemicals were also detected in at least one building above health comparison values and ambient air values during the DOH study including 1,1,2-trichloroethane; 1,2-dichloropropane; cis 1,3-dichloropropene; trichloroethene; and 1,1,2,2-tetrachloroethane.

Trichloroethene was detected in groundwater and soil gas during PSC's August 2000 sampling round. Cis 1,3-dichloropropene and 1,1,2-trichloroethane were detected in groundwater but not soil gas samples. Carbon tetrachloride was detected in soil gas only. Neither 1,2-dichloropropane or 1,1,2,2-tetrachloroethane were detected in soil gas or groundwater during the PSC' August 2000 study. However, 1,2-dichloropropane was detected in a small percentage of the January 2000 groundwater samples. No 1,1,2,2-tetrachloroethane was detected in any groundwater samples collected by PSC in January 2000. However, the detection limits for 1,1,2,2-tetrachloroethane were occasionally elevated.5 As a result, contaminated groundwater could be a source of the 1,1,2,2-tetrachlorethane detected in indoor air.

All the chemicals that exceeded the health comparison values and ambient air were carried forward for evaluation, which is presented in the discussion section of the health consultation report.

DOH Indoor Air Investigation, March 2001 and Concurrent PSC Soil Gas, Groundwater, and Ambient Air Study

An additional round of indoor air sampling was conducted by DOH in March 2001 to evaluate seasonal difference in indoor air quality and evaluate indoor air quality at some new locations identified by EPA. Because it appeared that rainfall could reduce the concentration of contaminants in soil gas and consequently indoor air, the sampling was conducted during a short period of no rainfall. Two of the residences and one business previously sampled in August 2000 were resampled: Residence 1, which was vacant during this sampling round; Residence 2; and Business 2. Three new residential locations (Residence 4, Residence 5, and Residence 6) and one new business location (Business 3) were determined by EPA to be potentially vulnerable to the shallow groundwater contamination and were added to sampling program. The locations in each building where samples were collected is summarized in Table A-3 (Appendix A) All the samples were collected in the breathing zone. Consistent with the DOH's August 2000 study, no screening level indoor air monitoring was conducted prior to sampling and people were not asked to leave their homes or businesses or limit their normal daily activities.

As in the previous DOH study, 6L Summa canisters prepared under negative pressure and equipped with flow regulators were used to collect the indoor air samples, which were collected over a 24-hour period except the sample at Residence 2 where the canisters operated for approximately 32 hours because the resident was not home at the end of the scheduled sampling event. All the samples were analyzed using EPA Method TO-15 using the SIM mode to obtain lower practical quantitation limits (PQLs).

While DOH collected indoor air samples, PSC conducted concurrent groundwater and soil gas sampling in the city right-of-way near the homes and businesses in an attempt to again establish a correlation between indoor air and groundwater contaminant concentrations. Soil gas samples were collected over an approximately 30-minute interval from soil probes that were screened from 4 to 6 feet bgs using Summa canisters with dedicated flow regulators. The soil gas probes were sealed with bentonite at the ground surface to prevent migration of ambient air along the outside of the soil gas probe. As done previously, the soil gas samples were analyzed using a modified version of EPA Method TO-14 in the SIM mode. Thirty-minute ambient air samples were also collected by PSC during the study. Groundwater samples were obtained from permanent wells using submersible pumps and temporary wells using a peristaltic pump. Samples collected with the peristaltic pump were obtained after purging one gallon of groundwater then pulling the tubing and collecting the sample from the bottom of the tubing to minimize the loss of the VOCs. Groundwater samples were obtained from the permanent wells using dedicated submersible pumps that were run at low flows (i.e., less than 300 ml/min.). The groundwater water samples were analyzed using EPA Method 8260 limited to the chemicals analyzed for the soil gas sampling.13 Table A-3 summarizes the analytical results. Chemicals reported as nondetected were assigned a value of one-half of the PQL.

Data Evaluation

Consistent with the previous evaluations, the indoor air sampling results were initially compared to health comparison values to begin identifying chemicals of potential health concern. All the chemical results that exceeded health comparison values were then compared to ambient air in attempt to identify chemicals that were potentially elevated as a result of contaminated groundwater rather than an indoor or outdoor air source. Ambient air samples collected by Philip during this study were only collected for 30 minutes. Although the samples were collected for a very short time period, the concentrations obtained from the 30-minute samples are similar to literature values for ambient air and were used for this evaluation.

Those VOCs that exceeded ambient air and/or indoor air literature values and health comparison values at each residence are shown on Table A-3 as bolded, shaded values. These chemicals were also seen in the August sampling round and were carried forward as COPC.

Table A-1: PSC August 2000 Indoor Air Results and Screening Values
Contaminant Screening Values (ug/m3) Indoor Air Results (ug/m3)
Health Comparison Value Ref.* 24-hour Outdoor Air Results Residence 1
Basement
Residence 2 Basement
1,1,1-trichloroethane 2300 25 2.4 3.2 2.1
1,1,2,2-tetrachloroethane 0.1 26b 0.10 0.10 0.41
1,1,2-trichloroethane 0.06 26b 0.08 0.08 0.19
1,1-dichloroethane 510 25 0.06 0.06 0.14
1,1-dichloroethene 0.02 26b 0.029 0.06 0.14
1,2,4-trichlorobenzene 210 25 NA NA NA
1,2-dichloroethane 0.04 26b 0.18 0.2 4.1
1,2-dichlorobenzene 330 25 0.09 0.09 0.21
1,2-dichloropropane 0.092 25 0.07 0.07 0.16
1,3-butadiene 0.004 26b NA NA NA
1,3-dichlorobenzene 3.3 25 0.09 0.09 0.21
1,4-dichlorobenzene 601 27 0.09 0.38 0.21
2-butanone 1000 25 NA NA NA
acetone 30,881 27 27 38 35
benzene 0.1 26b 5.4 3.9 1.6
bromoethane 19 27 NA NA NA
cis-1,2-dichloroethene 37 25 0.06 0.06 0.14
cis-1,3-dichloropropene 0.3 26b 0.07 0.07 0.16
carbon tetrachloride 0.07 26b 0.80 1 0.69
chlorobenzene 62 25 0.07 0.14 0.16
chloroform 0.04 26b 0.27 0.83 0.37
chloromethane 103 27 0.03 2 1.5
ethylbenzene 1.6 25 0.68 1.9 0.8
freon-11 730 25 NA NA NA
freon-113 31,000 27 0.11 0.70 2.8
freon-12 180 25 NA NA NA
m,p-xylene 434 27 2.1 5.8 2.2
methylene chloride 3 26b 1.7 130 330
o-xylene 434 27 0.67 1.7 0.7
tetrachloroethene 1.8 26b 2.7 2.6 1.4
styrene 256 27 0.20 0.62 0.41
trans-1,2-dichloroethene 793 26a 0.06 0.06 0.14
trichloroethene 0.009 26b 6.7 3.3 4.5
toluene 301 27 8.3 23 13
vinyl chloride 0.1 26b 0.019 0.15 0.044

Bolded and shaded values indicate the value exceeds health comparison value and outdoor air chemical concentration.
Italicized values represent one-half the detection limit for those contaminants that were below detection.

*25 - EPA Region III, RBCs; 26a- ATSDR EMEG; 26b-ATSDR CREG; 27-EPA Region IX RBCs


Table A-2: DOH August 2000 Indoor Air Study Results and Screening Values
Contaminant  Screening Values (ug/m3) Indoor Air Results (ug/m3)
Health Comparison Value Ref.* 24-hour Outdoor Air Results Residence 1
Basement
Residence 2
Basement
Residence 3
Basement
Business 1 Near Sump
1,1,1-trichloroethane 2300 25 2.4 0.74 0.74 4.42 0.74
1,1,2,2-tetrachloroethane 0.1 26b 0.10 1.61 1.61 1.61 1.61
1,1,2-trichloroethane 0.06 26b 0.08 0.65 0.65 0.65 0.65
1,1-dichloroethane 510 25 0.06 0.67 0.67 0.67 0.67
1,1-dichloroethene 0.02 26b 0.029 1.03 1.03 1.03 1.03
1,2,4-trichlorobenzene 210 25 NA 5.56 5.56 5.56 5.56
1,2-dichloroethane 0.04 26b 0.18 1.42 5.91 1.42 0.74
1,2-dichlorobenzene 330 25 0.09 0.66 0.66 0.66 0.66
1,2-dichloropropane 0.092 25 0.07 1.02 1.02 1.02 1.02
1,3-butadiene 0.004 26b NA NA NA NA NA
1,3-dichlorobenzene 3.3 25 0.09 0.60 0.60 0.60 0.60
1,4-dichlorobenzene 601 27 0.09 0.87 0.87 0.87 0.87
2-butanone 1000 25 NA 1.77 22.41 9.73 5.90
acetone 30,881 27 27 28.49 23.27 28.49 26.12
benzene 0.1 26b 5.4 0.65 0.65 0.65 1.50
bromomethane 19 27 NA 1.18 1.18 1.18 1.18
cis-1,2-dichloroethene 37 25 0.06 0.57 0.57 0.57 0.57
cis-1,3-dichloropropene 0.3 26b 0.07 0.77 0.77 0.77 0.77
carbon tetrachloride 0.07 26b 0.80 0.56 0.56 0.56 0.56
chlorobenzene 62 25 0.07 0.90 0.90 0.90 0.90
chloroform 0.04 26b 0.27 2.20 0.85 0.85 0.85
chloromethane 103 27 0.03 1.57 0.64 1.88 1.80
ethylbenzene 1.6 25 0.68 1.35 1.35 1.35 8.25
freon-11 730 25 NA 1.91 10.11 5.62 2.02
freon-113 31,000 27 0.11 0.61 0.61 0.61 2.30
freon-12 180 25 NA 2.92 3.36 11.86 3.26
m,p-xylene 434 27 2.1 5.21 1.74 3.99 27.78
methylene chloride 3 26b 1.7 93.75 180.55 18.75 4.17
o-xylene 434 27 0.67 1.32 1.32 1.32 6.08
tetrachloroethene 1.8 26b 2.7 1.32 1.49 1.49 6.44
styrene 256 27 0.20 1.23 0.57 0.57 0.57
trans-1,2-dichloroethene 793 26a 0.06 1.27 1.27 1.27 1.27
trichloroethene 0.009 26b 6.7 1.42 1.42 17.19 1.42
toluene 301 27 8.3 9.42 21.10 22.98 33.90
vinyl chloride 0.1 26b 0.019 0.74 0.74 0.74 0.74

Bolded and shaded values indicate the value exceeds health comparison value and outdoor air chemical concentration. 
Italicized values represent one-half the detection limit for those contaminants that were below detection.
  *25 - EPA Region III, RBCs; 26a- ATSDR EMEG; 26b-ATSDR CREG; 27-EPA Region IX RBCs


Table A-3: DOH March 2001 Indoor Air Study Results and Screening Values
Contaminant Screening Values (ug/m3) Indoor Air Results (ug/m3)
Health Comparison Value Ref.* 30-Minute Outdoor Air Results SG-9 30-Minute Outdoor Air Results SG-13 Residence 1
Basement
Resident 1
Basement
Residence 2
Basement
Residence 2
1st Floor
Residence 4
Crawl Space
Residence 4
1st Floor
1,1,1-trichloroethane 2300 25 0.39 0.25 3.8 4.1 2.2 3.0 0.4 0.3
1,1,2,2-tetrachloroethane 0.1 26b 0.12 0.11 0.3 0.2 0.2 0.2 0.2 0.2
1,1,2-trichloroethane 0.06 26b 0.10 0.08 0.3 0.1 2.2 0.1 0.1 0.1
1,1-dichloroethane 510 25 0.07 0.06 0.3 0.4 0.1 0.1 0.1 0.1
1,1-dichloroethene 0.02 26b 0.034 0.03 0.2 0.1 0.1 0.1 0.1 0.1
1,2,4-trichlorobenzene 210 25 NA NA 0.4 0.2 0.2 0.2 0.2 0.2
1,2-dichloroethane 0.04 26b 0.07 0.06 0.2 0.1 0.8 0.3 0.1 0.1
1,2-dichlorobenzene 330 25 0.10 0.09 0.3 0.2 0.2 0.2 0.2 0.2
1,2-dichloropropane 0.092 25 0.8 0.07 0.2 0.1 0.1 0.1 0.1 0.1
1,3-butadiene 0.004 26b NA NA NA NA NA NA NA NA
1,3-dichlorobenzene 3.3 25 0.10 0.09 0.3 0.2 0.2 0.2 0.2 0.2
1,4-dichlorobenzene 601 27 0.10 0.09 0.3 0.2 0.2 0.2 0.5 12
2-butanone 1000 25 NA NA 3.8 1.6 5.0 3.2 2.3 4.1
acetone 30,881 27 4.8 3.2 35.6 8.5 49.9J 49.9J 10.0 61.7
benzene 0.1 26b 3.1 2.2 1.9 1.8 1.4 1.4 2.3 3.8
bromomethane 19 27 NA NA 0.2 0.1 0.1 0.1 0.1 0.1
cis-1,2-dichloroethene 37 25 0.07 0.06 0.2 0.1 0.1 0.1 0.1 0.1
cis-1,3-dichloropropene 0.3 26b 0.08 0.07 0.2 0.1 0.1 0.1 0.1 0.1
carbon tetrachloride 0.07 26b 0.54 0.56 0.6 0.6 0.5 0.5 0.5 0.5
chlorobenzene 62 25 0.08 0.07 0.2 0.1 0.1 0.1 0.1 0.1
chloroform 0.04 26b 0.09 0.08 0.3 0.3 0.1 0.1 0.1 0.7
chloromethane 103 27 1.2 1.1 1.3 1.0 0.9 0.9 0.9 3.1
ethylbenzene 1.6 25 1.3 0.12 1.2 1.2 0.8 0.9 1.4 2.1
freon-11 730 25 NA NA 2.1 2.0 13.5 2.2 1.5 1.8
freon-113 31,000 27 0.13 0.12 1.0 1.0 2.0 0.6 0.6 0.6
freon-12 180 25 3.5 1 28.7 33.6 2.8 6.4 2.4 2.2
m,p-xylene 434 27 5.1 3.8 4.3 3.6 2.5 2.7 4.8 6.5
methylene chloride 3 26b 0.78 43 1.8 1.7 2.4 38.2 38.2 8.0
o-xylene 434 27 2 1.5 1.6 1.6 1.2 1.0 2.1 2.5
tetrachloroethene 1.8 26b 0.33 0.26 0.5 0.5 0.4 2.0 0.2 0.2
styrene 256 27 0.38 0.17 0.8 0.5 0.3 0.5 0.3 1.7
trans-1,2-dichloroethene 793 26a 0.34 0.30 0.2 0.1 0.1 0.1 0.1 0.1
trichloroethene 0.009 26b 0.09 0.08 0.3 0.3 0.3 2.8 0.4 0.3
toluene 301 27 7.3 5.6 11.7 7.5 5.3 8.7 7.9 24.1
vinyl chloride 0.1 26b 0.022 0.020 0.1 0.1 0.1 0.1 0.1 0.1

Boldedand shaded values indicate the value exceeds health comparison value and outdoor air chemical concentration. 
Italicized values represent one-half the detection limit for those contaminants that were below detection.

*25 - EPA Region III, RBCs; 26a- ATSDR EMEG; 26b-ATSDR CREG; 27-EPA Region IX RBCs


Table A-3: DOH March 2001 Indoor Air Study Results and Screening Values
Contaminant Screening Values (ug/m3) Indoor Air Results (ug/m3)
Health Comparison Value Ref.* 30-Minute Outdoor Air Results SG-9 30-Minute Outdoor Air Results SG-13 Residence 5
1st Floor
Residence 6
Basement
Business 2
Office
Business 3
Basement
1,1,1-trichloroethane 2300 25 0.39 0.25 0.4 0.7 120.0 0.7
1,1,2,2-tetrachloroethane 0.1 26b 0.12 0.11 0.2 0.2 0.2 0.2
1,1,2-trichloroethane 0.06 26b 0.10 0.08 0.1 0.1 0.1 0.1
1,1-dichloroethane 510 25 0.07 0.06 0.1 0.1 19.4 0.1
1,1-dichloroethene 0.02 26b 0.034 0.03 0.1 0.1 1.2 0.1
1,2,4-trichlorobenzene 210 25 NA NA 0.2 0.2 0.2 0.2
1,2-dichloroethane 0.04 26b 0.07 0.06 0.1 0.2 0.4 0.1
1,2-dichlorobenzene 330 25 0.10 0.09 0.2 0.2 1.6 0.2
1,2-dichloropropane 0.092 25 0.8 0.07 0.1 0.1 0.1 0.1
1,3-butadiene 0.004 26b NA NA NA NA NA NA
1,3-dichlorobenzene 3.3 25 0.10 0.09 0.2 0.2 0.2 0.2
1,4-dichlorobenzene 601 27 0.10 0.09 0.8 0.4 204.3 2.6
2-butanone 1000 25 NA NA 7.7 3.8 2.7 2.9
acetone 30,881 27 4.8 3.2 498.6 52.2 45.1 47.5J
benzene 0.1 26b 3.1 2.2 10.2 6.1 1.5 1.8
bromomethane 19 27 NA NA 0.1 0.1 0.1 0.1
cis-1,2-dichloroethene 37 25 0.07 0.06 0.1 0.1 16.6 0.1
cis-1,3-dichloropropene 0.3 26b 0.08 0.07 0.1 0.1 0.1 0.1
carbon tetrachloride 0.07 26b 0.54 0.56 0.8 0.6 0.6 0.5
chlorobenzene 62 25 0.08 0.07 0.1 0.1 0.1 0.1
chloroform 0.04 26b 0.09 0.08 1.7 0.1 0.8 0.7
chloromethane 103 27 1.2 1.1 9.3 1.0 0.9 0.9
ethylbenzene 1.6 25 1.3 0.12 3.4 3.5 5.2 1.0
freon-11 730 25 NA NA 1.9 46.1 2.5 1.6
freon-113 31,000 27 0.13 0.12 0.6 0.6 71.2 0.7
freon-12 180 25 3.5 1 2.6 8.4 2.4 2.6
m,p-xylene 434 27 5.1 3.8 10.4 12.6 17.4 3.3
methylene chloride 3 26b 0.78 43 3.3 1.7 3.8 2.4
tetrachloroethene 1.8 26b 0.33 0.26 0.8 0.5 1.4 0.4
styrene 256 27 0.38 0.17 4.7 3.8 1.1 0.5
trans-1,2-dichloroethene 793 26a 0.34 0.30 0.1 0.1 0.5 0.1
trichloroethene 0.009 26b 0.09 0.08 6.4 1.2 12.9 9.1
toluene 301 27 7.3 5.6 33.9 20.3 9.4 6.0
vinyl chloride 0.1 26b 0.022 0.020 0.1 0.1 0.1 0.1

Bolded and shaded values indicate the value exceeds health comparison value and outdoor air chemical concentration. 
Italicized values represent one-half the detection limit for those contaminants that were below detection.

*25 - EPA Region III, RBCs; 26a- ATSDR EMEG; 26b-ATSDR CREG; 27-EPA Region IX RBCs


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