Field Evaluation of Diffusive Samplers for Indoor Air VOC Measurements

1. Field Evaluation of Diffusive Samplers for Indoor Air VOC Measurements AIHce 2011 Heidi Hayes, Technical Director Robert Mitzel, Vice-President Business Development 1201

2. Outline • Introduction • Study Objectives • Sampler Selection • Field Sampling • Results • Conclusions

3. Conventional Air Sampling • Possible equipment failure • Requires experienced field sampler • Short duration (~24 hours) • Expensive to ship • Requires experienced field sampler • Short duration (~8 hours) • Sorbent type and sample volume selection is critical Summa Canisters Pumped Sorbent Tubes

4. Passive Sampling Practical Advantages • Reliable deployment with little training required • Unobtrusive • Inexpensive to ship Technical Advantages • Capable of generating trace level RLs • Long-term time-integrated measurements More representative indoor air concentrations and increased sensitivity are advantageous to health risk assessments.

5. Passive Sampling Concepts Measured in lab Analytical Result (µg) 1000 mL 1L 1000 L m3 X X Concentration (µg/m3) Uptake Rate (mL/min) Sampling duration (min) X Available in literature Dependent on Sampler Geometry Recorded in the field

6. Project Objectives • Sample integration of 1 to 7 days • Measurement of a wide VOC suite • Petroleum and chlorinated compounds • Reporting limits comparable to TO-15 SIM (~0.1 µg/m3) • Measured concentrations correlate with TO-15

7. Passive Samplers Sampler Geometries Tube Membrane Badge Radial Analytical Sensitivity Sorbent Sampling Rate Solvent WMS®- Charcoal SKC 575 3M OVM Radiello®130 Thermal Desorption ATD WMS®- TD SKC ULTRA Radiello®145 Lowest Highest

8. Passive Samplers Sampler Geometries Tube Membrane Badge Radial Sorbent Solvent Radiello®130 Thermal Desorption SKC ULTRA Radiello®145

9. Field Sampling – Case 1 • Indoor air samples collected • Duration 3, 4, and/or 7 days • Concurrent deployment • Radiello 130 – Charcoal • Radiello 145 – TD Sorbent • ULTRA III – TD sorbent

10. Results Good comparability was observed when detections on each sampler were sufficiently above their respective reporting limits.

11. Results • ULTRA III = 5-20 times greater sensitivity than the RAD-Charcoal. • ULTRA III had validated sampling rates for chlorinated breakdown products whereas RAD-TD required estimated rates. • Diffusive adsorption on the RAD-TD sorbent did not behave as predicted for these light VOCs (chloroform, 1,1-DCE) resulting in low bias. Stronger TD sorbent is required for these VOCs.

12. Results • One indoor air location was severely impacted with chlorinated solvents (100 to 10,000 µg/m3) • Sampling duration was 3 days. • Both Radiello-TD and ULTRA III exceeded capacity & TD-GC/MS. • Radiello-Charcoal had a higher capacity, and solvent extraction allowed for easy dilutions.

13. Field Sampling – Case 2 • Indoor air samples collected • 13 sites • Concurrent TO-15 cans & ULTRA III • Chlorinated solvents,petroleum products • 1 to 3 day duration

14. Results Strong correlation between ULTRA III and TO-15 concentrations across 3 orders of magnitude and at concentrations <0.1 µg/m3

15. Conclusions • Each passive sampler evaluated provided quantitative VOC indoor air measurements for TCE and PCE over a period of up to 7 days. • The larger surface area of charcoal provided an advantage over TD-sorbents when sampling high concentrations over multiple days.

16. Conclusions • ULTRA III-TD and Radiello-TD provide greater sensitivity than the Radiello-Charcoal over the 1-7 day period. • ULTRA III-TD provides a wider range of VOCs than Radiello-TD. • ULTRA III has a built-in blank correction allowing for improved accuracy at trace levels.