MANAGEMENT OF INDOOR RADON IN THE STATE OF OHIO

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DEVELOPED BY UNIVERSITY OF TOLEDO http//www.rado
n.utoledo.edu/
FUNDED BY OHIO DEPARTMENT OF HEALTH

• MANAGEMENT OF INDOOR RADON IN THE STATE OF OHIO

Ashok Kumar Charanya Varadarajan Suman
Maroju Department of Civil Engineering
University of Toledo
April 2007
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Different Sections of Ohio Information Web Site

• Information on Radon
• Health Risks
• Preventive Measures
• Radon Concentrations Across Ohio
• Homes
• Schools
• Water
• Mitigation
• Testing Procedures
• Geology of Radon
• Other sources of Information
• Lists of Radon Professionals
• F.A.Q

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OHIO RADON INFORMATION SYSTEM

• HOME
• SCHOOL
• MITIGATION
• TESTER
• WATER

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OBJECTIVE

• Store information on the home, school, water, and
  mitigation radon tests carried out in Ohio
• Analyze the radon data to yield specific results
  for better management and mitigation of radon in
  Ohio homes and schools
• Determine the removal efficiencies of the
  mitigation systems
• Provide to the public a radon information system
  on the web

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DATABASE

• Licensed contractors perform the tests and submit
  the test details to the Ohio Department of Health
  (ODH)
• Processed data stored in MS Access
• Queries built in MS access are used for the
  analysis of the data
• Reports of the analysis are submitted to the ODH
  every quarter

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HOMES DATABASE

• The most extensive database.
• Built as SQL Server 7.0/MS Access database.
• Data were obtained from government agencies,
  university researchers, and commercial testing
  companies.
• The many data sets were combined to produce a
  unified database that includes 1500 zip code
  areas in Ohio.
• Vast majority of the data (something over 95
  percent) comes from houses where the tests were
  done by the homeowners using either charcoal
  canisters or alpha-track detectors.
• About 93 percent of the data were sent on
  computer disks and so were transferred without
  transcription errors.

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Homes Main Table
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Statistics for the State of Ohio
Unit- pCi/l
Total Number of Records 139,152
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Results

• Total number of counties in Ohio - 88
• Number of counties having GM indoor radon
  concentration more than 4.0 pCi/l is 23 (was 29
  in 2006 see Table 1)
• Licking is the only county with GM of radon
  concentration greater than 8 pCi/l

Table 1 Counties currently below 4pCi/l
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Results

• Zip codes in the database 1500
• Incorrect zip codes 243
• Correct zip codes - 1257
• Number of zip codes having geometric mean indoor
  radon concentration more than 4.0 pCi/l - 442

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• Individual County Maps Showing Variation
• among Zip Codes

Unavailability of Complete zip code shapefile
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Zip code Statistics Table - Licking
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SCHOOL DATABASE

• SHORT-Term and LONG-Term test data
• 865 Radon School Tests
• Complete Information - 852
• Schools long term tested 154

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• The ODH School
• Testing
• Program has covered 865 schools in 41 counties

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Schools with Concentration Greater than 20 pCi/l
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Schools with More than 5 Rooms 10 pCi/l
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Statistics for School Counties with GM of Radon
Concentration 4 pCi/l
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Summary of Results

• Total number of counties tested -42
• Total number of schools tested (Short term) -
  865 (852 complete)
• Total number of schools showing maximum radon
  concentration in any single room greater than
  4 pCi/l - 259

• Total number of rooms tested - 28649
• Total number of rooms having radon concentration
  greater than or equal to action level of 4
  pCi/l -1694

Approximately 30.5 of schools in Ohio have a
potential for at least one room in excess of the
USEPA action level (4 pCi/l) compared to 19.3
nationwide.
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MITIGATION DATABASE

• 17, 089 records
• 15 different types of systems have been reported
  by the contractors

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Number of Records with Pre-Mitigation Level
between 4 pCi/l and 20 pCi/l for Years 2001 to
2006
Number of Records with Removal Less Than 50 For
Years 2001 to 2006
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Average Removal Efficiency by Each Type of
System (2001)
Note Blue identifies the best performing system
Grey identifies the second best performing system
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Average Removal Efficiency by Each Type of
System (2002)

• Note Blue identifies the best performing system
  Grey identifies the second best performing system

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Average Removal Efficiency by Each Type of
System (2003)

• Note Blue identifies the best performing system
  Grey identifies the second best performing system

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Average Removal Efficiency by Each Type of
System (2004)
Note Blue identifies the best performing system
Grey identifies the second best performing system
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Average Removal Efficiency by Each Type of
System (2005)
Note Blue identifies the best performing system
Grey identifies the second best performing system
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Average Removal Efficiency by Each Type of
System (2006)
Among the 40 different combinations of mitigation
systems, these are some of the best performing
systems. The other systems and combinations have
very few records to substantiate the high removal
efficiency.
Note Blue identifies the best performing system
Grey identifies the second best performing system
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Variation of Removal Efficiency with Pre- and
Post Mitigation Level for Best Performing System
for the Year 2003
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Variation of Removal Efficiency with Pre- and
Post-Mitigation Level for Best Performing System
for the Year 2004
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Variation of Removal Efficiency with Pre- and
Post-Mitigation Level for Best Performing System
for the Year 2005
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Variation of Removal Efficiency with Pre- and
Post-Mitigation Level for Best Performing System
for the Year 2006
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Summary

• Most efficient system in Ohio for the year 2001
  -2006 is Sub-slab Depressurization System
• Efficiency is a function of pre-mitigation and
  post-mitigation levels
• Efficiency of the mitigation systems decreases
  with decrease in pre-mitigation level as
  concentrations cannot be reduced below a certain
  level
• Efficiency of the mitigation system decreases
  with increase in the post-mitigation level

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TESTERS DATABASE

• Stores the information on the radon tests
• Hard copy of the test information submitted to
  ODH is computerized at the UT and is stored in a
  tabular form for easy access and analyses
• Data is queried in MS Access to arrive at key
  statistics for radon measurements in all zip code
  areas and counties
• Arithmetic mean, geometric mean, standard
  deviation, variance, maximum and minimum observed
  concentrations are calculated
• 44,864 records in the database

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Statistics for Counties with GM of Radon
Concentration 4 pCi/l
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Zip codes with GM of radon concentration greater
than 4 pCi/l

• Number of Zip codes greater than 4 pCi/l 254
• Number of Zip codes greater than 8 pCi/l 60
• Number of Counties greater than 4 pCi/l 21
• Number of Zip codes greater than 8 pCi/l 2

Number of zip codes tested - 853 Number of
counties tested - 84
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WATER DATABASE

• Water database consists of two sets of controls -
  public water wells and private water wells.
• Ohio EPA provided the information on public
  water wells.
• Information on private water wells were
  synthesized from M.S. theses completed at Ohio
  Universities.

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Radon Concentration in Private Water Wells in
Counties of Ohio
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Results

• 65 wells of the 1065 private water supply data
  have concentrations over 1000 pCi/l
• 28 in Logan County and 13 in Delaware
• 7 wells have concentration over 3000 pCi/l
• No public water supply system has concentration
  greater than 1500 pCi/l

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Conclusions

• A successful integrated Ohio Radon Information
  System
• The information helps is assessing the extent of
  radon problem
• The best mitigation systems are determined
• Website helps in creating awareness

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Comments

• Informed of error in the county listing of some
  public water wells in the dataset
• Updated the website with the newest radon
  statistics
• Developed and posted on the web individual county
  maps showing the variation of radon in each zip
  code

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• New Work-
• GIS Interpolation Techniques for Radon Data

• To evaluate the best Interpolation technique for
  the radon concentrations data
• To evaluate the radon concentrations for
  unmeasured zip code locations in Ohio using the
  best Interpolation technique

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Interpolation Techniques

• Kriging
• Inverse Distance Weighting
• Radial Basis Function
• Local Polynomial Interpolation
• Global Polynomial Interpolation

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Acknowledgements

• Ohio Department of Health/ USEPA
• Dr. Jim Harrell and Dr. Andrew Heydinger
  (University of Toledo)
• Graduate students
• Staff members of the ODH

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• Thank you!!