EPA Vapor Intrusion Database Preliminary Analysis of Attenuation Factors Helen Dawson, Ph.D US EPA, Region 8, Denver, CO Vapor Intrusion Workshop AEHS Spring 2008, San Diego, CA
Acknowledgments Ian Hers Golder and Associates, Vancouver, B.C., Canada Robert Truesdale RTI International, Research Triangle Park, NC, USA William Wertz New York State Department of Environmental Conservation, NY, USA Todd McAlary Geosyntec Consultants, Toronto, Ontario, Canada 2
Presentation Outline Database evaluation considerations Impact of background on attenuation factors Groundwater-to-indoor air attenuation Soil gas-to-indoor air attenuation Subslab-to-indoor air attenuation Crawlspace-to-indoor air attenuation 3
Database Evaluation Considerations Data quality Handling of data reported below a given reporting limit Differences in site conditions and the types of data compiled Spatial and temporal variability in media concentrations 4
Differences in Site Conditions and Types of Data Compiled 100% 90% 80% 70% 60% Soil 4 V. Coarse Multi-Use >200 2 3 2 4 8 Non-Residential 10-50 25 Coarse 50% 40% 30% 37 Groundwater 34 Residential 31 <10 20% 10% 0% 13 Fine Vapor Source Soil Type Building Use Num. Buildings 5
Spatial & Temporal Variability Spatial Variability Temporal Variability Graphics by EnviroGroup Limited 6
Indoor Air Spatial Variability 1,1 DCE REF Indoor Air REF REF REF Redfield Facility REF Denver, CO D. Folkes, 2000 1,1 DCE RESULTS (µg/cubic meter) >45 REF REF 4.6 to 45 0.46 to 4.5 <=0.46 NEGATIVE NUMBER INDICATES RESULT BELOW DETECTION LIMIT REF REFUSED ACCESS FOR SAMPLING/NO RESPONSE APPROXIMATE EXTENT OF DETECTED VOLATILE ORGANIC COMPOUND IN GROUNDWATER FORMER REDFIELD FACILITY D. Folkes 7
Indoor Air Temporal Variability Lowry Air Force Base, CO Indoor Air Concentration (ug/m3) 60 50 40 30 20 10 0 UA03 UA22 UA25 H. Dawson Jan-00 Apr-00 Jul-00 Sep-00 Dec-00 Mar-01 T. McAlary 8
Sub-Slab Spatial Variability New York State Dept. of Health C TCE Soil Vapor & Sub-slab Vapor (ug/m3) K. Anders 9
Subslab Spatial Variability 1,1,1-TCA 1,1-DCE TCE c-1,2-dce 76 64 17 1.4 1,1,1-TCA 1,1-DCE TCE c-1,2-dce 542 480 189 46 1,1,1-TCA 1,1-DCE TCE c-1,2-dce 52 31 31 9.5 D. DiGiulio 10
Sub-Slab Temporal Variability 10000 Sub-Slab Concentration (ug/m3) 1000 100 10 UA03 UA05 UA18 UA21 UA22 UA24 UA28 1 Mar-00 May-00 Jun-00 Aug-00 Oct-00 Nov-00 Jan-01 Feb-01 Date H. Dawson 11
Soil Gas Spatial Variability Soil Gas (ug/m3) Lowry Air Force Base 1000 100 10 1 0.1 0.01 0.1 1 10 Indoor Air (ug/m3) 12
Soil Gas Temporal Variability Endicott, NY Soil Gas Groundwater W. Wertz 13
Exterior Soil Gas vs. Subslab Depth bgs (m) 0-1 -2-3 -4-5 -6-7 -8 Css 0.5 0.6 0.8 0.9 Cnb 0.4 0.3 0.2 0.1 0.01 1E-3 0 2 4 6 8 10 12 Cnb: near building soil gas concentration Css: subslab concentration 1E-6 1E-5 1E-4 x (m) L. Abreu, 2006 14
Exterior Soil Gas vs. Subslab 1.E+05 Subslab Concentration (ug/m3) 1.E+04 1.E+03 1.E+02 1.E+01 Subslab > Soil Gas 1.E+00 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Soil Gas Concentration (ug/m3) H. Dawson 15
Impact of Background on Empirical Attenuation Factors AF emp = (C ia-vi + C ia-bkgd )/C subsurface 10000.0 PCE 111TCA TCE 11DCE 1000.0 100.0 Max 10.0 95th % 1.0 50th % 0.1 0.0 Background Database Background Database Background Database Background Database 16 Concentration (ug/m3)
Impact of Background on Empirical Attenuation Factors 10000 Indoor Air Concentration (ug/m3) 1000 100 10 1 0.1 Plateau from Background Influence Background conc. No Background Influence 0.01 1 10 100 1000 10000 100000 1000000 Source Vapor Concentration (ug/m3) 17
Background Indoor Air Concentrations Compound N Studies N Samples %Detect RL Range 25% N 50% N 75% N 90% N 95% N Max N Benzene 16 2672 87 0.05-1.6 1.5 7 2.4 16 4.7 9 10 11 16 5 36 14 Carbon Tetrachloride 5 873 88 0.15-0.25 0.4 2 0.5 5 0.7 2 0.9 4 1.1 1 2.6 3 Chloroform 11 2210 73 0.02-2.4 0.6 4 1.0 11 2.4 6 4.1 8 6.8 5 10.6 9 Dichloroethane,1,1-5 1309 0.3 0.08-2.0 <RL 5 <RL 5 <RL 5 <RL 5 <RL 4 0.9 5 Dichloroethene, 1,1-5 957 10 0.01-2.0 <RL 4 <RL 5 0.4 5 0.8 5 1.4 3 4.1 5 Dichloroethene, cis 1,2-4 975 3 0.25-2.0 <RL 4 <RL 4 <RL 4 <RL 4 1.2 3 7.4 4 Dichloroethene, trans 1,2-3 575 0 0.8-2.0 <RL 3 <RL 3 <RL 3 <RL 3 <RL 2 <RL 3 Ethylbenzene 12 1541 81 0.01-2.0 1.2 4 2.2 12 2.8 5 8.9 7 13 3 35 10 Methyl tert-butyl ether (MTBE) 4 502 47 0.05-1.8 <RL 3 0.8 4 6.2 4 32 4 72 2 248 4 Methylene chloride 7 1,649 73 0.4-3.5 0.46 3 1.10 7 3.2 5 11 7 16 4 163 6 Tetrachloroethene 15 2369 65 0.03-3.4 <RL 7 0.7 13 1.4 6 3.8 10 7.5 5 42.0 13 Toluene 14 2122 96 0.03-2.0 7 5 13 14 25 7 54 9 90 4 139 12 Trichloro-1,2,2-trifluoroethane, 1 1 400 56 0.25 <RL 1 0.5 1 1.1 1 1.8 1 3.4 1 7 1 Trichloroethane, 1,1,1-9 1877 60 0.12-2.7 1.1 7 1.8 9 2.6 7 3.1 7 6.9 5 102 8 Trichloroethene 14 2435 44 0.02-2.7 0.06 6 0.2 11 0.1 6 0.5 9 0.8 5 19 11 Vinyl chloride 6 1684 7 0.01-1.3 <RL 6 <RL 6 0.02 6 0.03 6 0.05 5 0.4 6 Xylene, m/p- 10 1920 90 0.4-2.2 2.5 6 4.0 10 7.6 7 21 9 38 4 279 8 Xylene, o- 14 2061 85 0.11-2.2 1.4 6 2.2 14 3.3 7 11 9 13 4 44 12 18
Impact of Background on Empirical Attenuation Factors 1.E+04 Indoor Air Concentration (ug/m3) 10000 1000 100 10 1 0.1 Background Influence No Background Influence 0.01 1 10 100 1000 10000 100000 1000000 Source Vapor Concentration (ug/m3) Indoor Air Concentration (ug/m3) Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Subslab (ug/m3) 1.E+04 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) EPA Data (IA < RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Subslab (ug/m3) 19
2008 Database Attenuation Factor Type 2002 Database Attenuation Factors Screening Data Quality Screen a Subsurface Concentration Screen b Data Set 1 Data Consistency Screen c Data Set 1: Subsurface and indoor air concentrations >RL Data Set 2 95 th Percentile Background Screen d groundwater to indoor air 1,058 1,026 910 596 soil gas to indoor air 237 226 218 86 subslab to indoor air 1,584 1,553 991 311 crawlspace to indoor air 110 110 110 45 Total 2,989 2,915 2,229 1,038 Data Set 2: Sbset of Data Set 1 (2002) > geomean background 20
Groundwater-to-Indoor Air Attenuation Cumulative Percentile Plots 1.0E+00 Data Set 1 2002 vs 2008 Groudwater Attenuation Factor 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 Data Set 1 (2002) Data Set 1 (2008) 1.0E-07 0% 20% 40% 60% 80% 100% Cumulative Percentile 1.0E+00 Data Set 2 2002 vs 2008 Groudwater Attenuation Factor 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 Data Set 2 (2002) Data Set 2 (2008) 1.0E-07 0% 20% 40% 60% 80% 100% Cumulative Percentile 21
Groundwater-to-Indoor Air Attenuation 1.E+04 Data Set 1 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) EPA Data (IA < RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Groundwater Vapor (ug/m3) 1.E+04 Data Set 2 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Groundwater Vapor (ug/m3) 22
Groundwater-to-Indoor Air Attenuation Box Whisker Plots 1.0E+00 1.0E-01 1.0E-02 Max 1.0E-03 95th% 1.0E-04 50th% 1.0E-05 1.0E-06 5th% Min 1.0E-07 Data Set 1 (2002) Data Set 1 (2008) Data Set 2 (2002) Data Set 2 (2008) 23 Groundwater AF
Groundwater-to-Indoor Air Attenuation 1.0E-01 Chemical 1.0E-01 Building Use 1.0E- 01 Soil Type Under Slab Groundwater AF 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 Max 95th% 50th% 5th% Min Groundwater AF 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 Max 95th% 50th% 5th% Min Groundwater AF 1.0E- 02 1.0E- 03 1.0E- 04 1.0E- 05 1.0E- 06 Max 95th% 50th% 5th% Min 1.0E-07 All CHCs 11DCE TCE PCE cis12dce All PHCs 1.0E-07 Residential Commercial 1.0E- 07 Fine Coarse V.Coarse 24
1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 1.0E-07 Groundwater-to-Indoor Air Attenuation Individual Site Box Whisker Plots Groundwater AF for Individual Sites 25 Groundwater AF > 500 X BKG Allepo BillingsPCE BP Site CDOT Davis Eau Claire Endicott Fresh Water Lens Grants Hamilton- Sundstrand Harcros/Tri State Hopewell Precision Jackson LAFB Lakeside Village Lockwood All MADEP Moffet MCH Mount Holly Mountain View Rapid City Redfield SCM - Cortlandville Stafford Twins Inn Uncasville Wall West Side Corporation WZ CA Bay
Soil Gas-to-Indoor Air Attenuation 1.E+04 Data Set 1 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) EPA Data (IA < RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Soil Gas (ug/m3) 1.E+04 Data Set 2 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Soil Gas (ug/m3) 26
Soil Gas-to-Indoor Air Attenuation Box Whisker Plots 1.0E+01 1.0E+00 Soil Gas AF 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 Max 95th% 50th% 5th% Min 1.0E-06 Data Set 1 (2008) Data Set 2 (2008) 27
1.0E+01 1.0E+00 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 Soil Gas-to-Indoor Air Attenuation Individual Site Box Whisker Plots Soil Gas AF for Individual Sites Max 95th% 50th% 5th% Min 28 Soil Gas AF > RL Alameda Allepo Alliant BP Site CA Dry Cleaners Endicott Fresh Water Lens Georgetown Grants Harcros/Tri State Jackson MADEP1 Mountain View Rapid City SCM - Cortlandville Stafford Uncasville West Side Corporation
Subslab-to-Indoor Air Attenuation Cumulative Percentile Plots 1.0E+00 Data Set 1 (2002) Data Set 1 2002 vs 2008 Subslab Attenuation Factor 1.0E-01 1.0E-02 1.0E-03 1.0E-04 Data Set 1 (2008) 1.0E-05 0% 20% 40% 60% 80% 100% Cumulative Percentile 1.0E+00 Data Set 2 (2002) Data Set 2 2002 vs 2008 Subslab Attenuation Factor 1.0E-01 1.0E-02 1.0E-03 1.0E-04 Data Set 2 (2008) 1.0E-05 0% 20% 40% 60% 80% 100% Cumulative Percentile 29
Subslab-to-Indoor Air Attenuation 1.E+04 Data Set 1 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) EPA Data (IA < RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Subslab (ug/m3) 1.E+04 Data Set 2 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Subslab (ug/m3) 30
Subslab-to-Indoor Air Attenuation 1.E+04 Data Set 2 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Subslab (ug/m3) 1.E+04 Data Set 2 2008 & SS > 50xBkgd Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Subslab (ug/m3) 31
1.0E+00 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 Subslab-to-Indoor Air Attenuation Box Whisker Plots Max 95th% 50th% 5th% Min Data Set 1 (2002) Data Set 1 (2008) Data Set 2 (2002) Data Set 2 (2008) 32 Subslab AF
Subslab-to-Indoor Air Attenuation Subslab AF and Vapor Source Strength 1.0E+00 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 > RL > 1 X BKG > 10 X BKG > 50 X BKG > 100 X BKG > 500 X BKG Subslab AF Max 95th% 50th% 5th% Min 33
1.0E+00 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 Subslab-to-Indoor Air Attenuation Individual Site Box Whisker Plots Subslab AF for Individual Sites Max 95th% 50th% 5th% Min 34 Subslab AF > 50 X BKG Alameda BillingsPCE DenverPCEBB Endicott Georgetown Harcros/Tri State Hopewell Precision LAFB Orion Park Raymark SCM - Cortlandville Stafford West Side Corporation
Crawlspace-to-Indoor Air Attenuation 1.E+04 Data Set 1 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Crawlspace (ug/m3) 1.E+04 Data Set 2 2008 Indoor Air Concentration (ug/m3) 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 EPA Data (IA > RL) Alpha = 1.0 Alpha = 1E-1 Alpha = 1E-2 Alpha = 1E-3 Alpha = 1E-4 Alpha = 1E-5 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 Crawlspace (ug/m3) 35
1.0E+01 1.0E+00 1.0E-01 1.0E-02 Crawlspace-to-Indoor Air Attenuation Max 95th% 50th% 5th% Min Data Set 1 (2008) Data Set 2 (2008) 36 Crawlspace AF
Crawlspace-to-Indoor Air Attenuation Individual Site Box Whisker Plots 1.0E+01 Crawlspace AF for Individual Sites Max 1.0E+00 1.0E-01 1.0E-02 > RL Grants Jackson LAFB Lockwood Crawlspace AF 95th% 50th% 5th% Min 37
Summary & Conclusions 1.0E+01 Data Set 1 1.0E+00 Attenuation Factor 1.0E-01 1.0E-02 1.0E-03 1.0E-04 1.0E-05 Max 95th% 50th% 5th% Min 1.0E-06 1.0E-07 Groundwater Soil Gas Subslab Crawlspace 38
Summary & Conclusions 1.0E+01 Data Set 2 1.0E+00 1.0E-01 Max 1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06 1.0E-07 GW > RL SG > RL SS > RL CS > RL Attenuation Factor 95th% 50th% 5th% Min 39
Summary & Conclusions 41 sites, 15 states, 913 buildings, 21 chemicals: mostly groundwater vapor sources, chlorinated hydrocarbons, residential buildings. Influence of background sources on indoor air concentrations needs to be considered in vapor intrusion investigations The range of attenuation factors for any given site spans several orders of magnitude; attributed to spatial and temporal variability and/or nonrepresentative samples The attenuation factor distributions obtained for each of the media are generally consistent with the conceptual model for vapor intrusion. 40