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Air Toxics LTD Laboratory Services Since 1989 Field Evaluation of Diffusive Samplers for Indoor Air VOC Measurements AIHce 2011 Heidi Hayes, Technical.

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Presentation on theme: "Air Toxics LTD Laboratory Services Since 1989 Field Evaluation of Diffusive Samplers for Indoor Air VOC Measurements AIHce 2011 Heidi Hayes, Technical."— Presentation transcript:

1 Air Toxics LTD Laboratory Services Since 1989 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 CanistersPumped 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 Concentration (µg/m3) Analytical Result (µg) Uptake Rate (mL/min) Sampling duration (min) 1000 mL 1L 1000 L m3 X XX Recorded in the fieldAvailable in literature Dependent on Sampler Geometry Measured in lab

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/m 3 ) Measured concentrations correlate with TO-15

7 Passive Samplers Tube Solvent Membrane Thermal Desorption RadialBadge SKC 575 3M OVM SKC ULTRARadiello®145 WMS®- TD ATD Radiello®130 WMS®- Charcoal Analytical Sensitivity Sampling Rate LowestHighest Sampler Geometries Sorbent

8 Passive Samplers Tube Solvent Membrane Thermal Desorption RadialBadge SKC ULTRARadiello®145 Radiello®130 Sampler Geometries Sorbent

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/m 3

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.


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