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

Outline Introduction Study Objectives Sampler Selection Field Sampling Results Conclusions

Conventional Air Sampling Summa Canisters Pumped Sorbent Tubes 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

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.

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

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

Analytical Sensitivity 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

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

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

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

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.

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.

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

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

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.

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.