1. National WAP Evaluation: Radon
Paul Francisco
University of Illinois at Urbana-Champaign

2. IAQ Study One of many studies in the National WAP Evaluation
Conducted in
Several contaminants assessed
Temperature/Relative Humidity
Mold/Moisture
Carbon Monoxide
Formaldehyde (25% of homes)
RADON

3. Sampled Geographic Areas
~ 500 homes from 77 agencies in 35 States; high radon areas oversampled

4. Sampling Design Groups of 8 homes within an agency’s territory
5 treatment
3 control
All homes tested about 3-6 weeks before and after weatherization of treatment homes
Samplers deployed within a 3-day period
5-7 day tests

5. Radon Sampling – Instrumentation
Used diffusion barrier charcoal canisters provided by EPA – Las Vegas lab
Analysis done by EPA Las Vegas lab
1 of 16 canisters received duplicate
1 of 16 canisters received blank

6. Radon Sampling – Location
Every first floor
Every basement and crawl space
No samplers below manufactured homes
Followed standard placement rules

7. Analysis “Difference-of-differences”
Pre-post change for treatment
Pre-post change for control
Difference of these changes
Evaluated many explanatory factors, e.g.
Outdoor temperature
Air change rate (blower door and modeled natural airflow)
Precipitation
Ventilation
Etc.

8. RESULTS

9. Radon Results (Arithmetic Means) N Change (Post – Pre), pCi/L
Treatment
Group
Control Group
Net (Treatment – Control)
Overall
all cases
447
+0.14
±0.13
-0.29
±0.18
+0.44
preWX radon <10 pCi/L
438
+0.11
±0.12
-0.16
+0.28
±0.14
EPA radon zone
High (Zone 1)
234
+0.29
-0.50
±0.33
+0.79
±0.31
Moderate (Zone 2)
170
+0.10
±0.26
-0.11
±0.25
+0.23
±0.28
Low (Zone 3) 43
-0.10
+0.01
±0.20

10. Significant factors All cases included:
Estimated change in natural infiltration rate
Change in outdoor temperature
Change in fraction of days with rain
Addition of mechanical ventilation
Replacement of heating system with sealed combustion
Remove cases with changes greater than 3x (n=8):

11. FOLLOW-UP NATIONAL WAP STUDY:
ADDED EXHAUST VENTILATION per ASHRAE 62.2

12. Study Design Selected 18 homes with levels between 4 and 8 pCi/l
Add exhaust ventilation per ASHRAE
Controls performed “on-off” operation of fan in 1-week increments
Look at changes from week-to-week

13. Sample Home Exhibiting Reductions in Radon When Ventilation is On

14. Overall results

15. HISTORY CONTEXT

16. Timeline SWS specify expected outcomes from various retrofit actions.
2010
2011
2012
2013
IAQ Study in Heating Climates
Follow-up on Exhaust Ventilation
IAQ Results Made Available to WAP
Standard Work Specifications (SWS) Development Initiated
WPN 11-6 Implemented
ASHRAE 62.2 Enacted by WAP
SWS Complete and Workforce Guidelines Published
WAP Implements Quality Work Plan
EPA HIEP Available to Public
SWS specify expected outcomes from various retrofit actions.
Includes ventilation / health & safety
WPN 11-6: Health & Safety guidance for WAP. Includes
precautions regarding radon
EPA recognizes “do no harm” principle

17. QUESTIONS?
Paul Francisco