2014/15 national radon survey methodology and preliminary ... · 2014/15 national radon survey...
TRANSCRIPT
![Page 1: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/1.jpg)
2014/15 National Radon Survey
Methodology and Preliminary Results
Dr. Patrick Murphy
UCD School of Mathematical Sciences
![Page 2: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/2.jpg)
The 2014/15 project was led by the EPA
with Statistical Advice and Analysis
provided by UCD
![Page 3: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/3.jpg)
Outline
• Background
• Sampling and Methodology
• Data
• Analysis
• Preliminary Results
• Significance of Results
• Future Work
![Page 4: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/4.jpg)
Background
![Page 5: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/5.jpg)
THE National Radon Survey
• Conducted between 1992-1999
• 10km Grid Squares
• 11,319 houses measured
• 12 Month Measurements
• 89Bq/m3 average indoor conc.
• Formed basis for map, all future work and
legislation
![Page 6: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/6.jpg)
NEW National Radon Survey - Why?
• Previous Survey now 15 years old
• Substantial number of houses built since 1999
• Has average indoor concentration changed?
• Is risk to population different?
• Effect of building legislation?
![Page 7: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/7.jpg)
Methodology
![Page 8: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/8.jpg)
Methodology
• Replicate Previous Methodology?
• Cost & Time - Limitations
• Sampling
![Page 9: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/9.jpg)
Methodology
• 3 Month instead of 12 Months (Based on
Previous Research conducted by EPA and UCD)
• Stratified Sample of 60 Grid Squares with
Higher Response Rate to Previous NRS
• Stratified by Geography and Radon Level
• Invitation followed by Household Survey plus
Detectors
• Issued Aug, Sept & Oct 2014
![Page 10: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/10.jpg)
Data
![Page 11: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/11.jpg)
Data
• Addresses Selected from Geo-Directory
• Invitation Letters: Non Contacts ~ 3%
• 755 questionnaires issued
• 573 Questionnaires returned
• 548 Accepted
![Page 12: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/12.jpg)
Data
• 649 houses returned usable detectors
• Living room and Bedroom detectors as in
Previous NRS
• All 649 houses included in National
Average
![Page 13: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/13.jpg)
Data
• Further analysis by house type required
matching records from questionnaire and
detectors returned
• 542 usable matches
![Page 14: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/14.jpg)
Analysis
![Page 15: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/15.jpg)
Analysis
• Outlier Detection
• Check for Lognormality
• Check for Bias due to response rate and length of
detection period
• Weighting of Data
• New National Average
• Analysis by House Type and Year of Construction
![Page 16: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/16.jpg)
Results
![Page 17: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/17.jpg)
Preliminary Results
• No Significant Outliers
• Data found to be Lognormal
• No Bias: Responses not-correlated with
previous NRS Radon Levels
• No Bias due to detection period
• Weighting performed
![Page 18: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/18.jpg)
Preliminary Results
New National Average Indoor Radon
Concentration
• Previous NRS 89.27 Bq/m3
• New NRS 77.03 Bq/m3
• 95% Confidence Interval
(71.07 Bq/m3 , 83.49 Bq/m3)
![Page 19: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/19.jpg)
Preliminary Results
Results by Year of Construction
• Previous NRS 89.27 Bq/m3
• New NRS Pre 98 Avg 86.14 Bq/m3
• New NRS Post 98 Avg 64.23 Bq/m3
![Page 20: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/20.jpg)
Significance of Results
![Page 21: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/21.jpg)
Significance of Results
• Impact of past 15 years of work by
RPII/EPA
• Awareness
• Building Regulations
• Remediation
• Still a long way to go
![Page 22: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/22.jpg)
Future Work
![Page 23: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/23.jpg)
Future Work
• Incorporate information on Population
Density to produce Population Average
and Risk Measurements
![Page 24: 2014/15 National Radon Survey Methodology and Preliminary ... · 2014/15 National Radon Survey Methodology and Preliminary Results Dr. Patrick Murphy UCD School of Mathematical Sciences](https://reader030.vdocuments.mx/reader030/viewer/2022040621/5f355d43c3a59951964fa407/html5/thumbnails/24.jpg)
Thank You