A Novel Downwind Odor Sampling Strategy for Transient Events
Transcript of A Novel Downwind Odor Sampling Strategy for Transient Events
A Novel Downwind Odor Sampling Strategy for Transient Events
D. Wright – Don Wright & Associates, LLC F. Kuhrt & A. Iwasinska – Microanalytics-MOCON
D. Eaton – Epsilon CompanyJ. Koziel – Ag and Biosystems Engineering, Iowa State University
Acknowledgement
This work has been partially funded by the US Department of Agriculture under SBIR Phase II Grant – CSREES Award number 2007-33610-18619 to Microanalytics.
However
Any opinions, findings, conclusions, or recommendations expressed in this presentation are those of the author and do
not necessarily reflect the view of the US Department of Agriculture
Cereal Packaging Film – ‘Barnyard’ Malodor
‘Bad’ Film p-cresol
‘Good’ Film p-cresol
Conclusions from Project Report into Swine CAFO Study - 1996
It appears that p-cresol may be a priority odor impact compound relative to the swine-barn application.
If this is proven correct, sampling these environments with plastic bags is ill-advised.
The priority impact shown for phenol is believed to be a cross-contamination artifact; unrelated to the targeted swine-barn source.
Published References Addressing the Issue of Odorant Loss in Tedlar Bags
Keener et. al.; 2002; Evaluation of thermal desorption for the measurement of artificial swine odorants in the vapor phase; NC State, Transactions of the ASAE.
Koziel et. al.; 2005; Evaluation of sample recovery of malodorous livestock gases from air sampling bags, SPME fibers, Tenax TAsorbent tubes and sampling canisters; Texas A&M, JAWMA.
Trabue et.al.; 2006; Bias of Tedlar bags in the measurement of agricultural odorants; USDA-ARS Iowa, J of Environmental Quality.
Whole-Air Sample Bag Materials Optimization
Comparative p-Cresol Loss;Tedlar™ Versus m-FEP
753075Tedlar™
323075m-FEP
14123m-FEP
343075m-FEP
% LossHold Time (min)Temperature °CFilm Type
Prototype Inverted Metalized Film Sampling Bag
Sorbent Tube
Inert gas
Inertized, Heat-tracedReconstitute Canister
Comparative Phenol Loss Percentages for Various Films and Foils
9768726275T=0 + 22 hr
7549434050T=0 + 2.75 hr
5938332922T=0 + 1.5 min
NickleFoil
InvertedInc / Ag
w/o BHA
InvertedInc / Ag w BHA
InvertedAluminum
M-FEPStorageTime
Sorbent Tube to Whole-Air Sample
Thermal Reconstitution
ort
CombiPAL Autosampler
Cycle ComposerController
Patent Pending
Inert gas
Servo Drive
Heat-tracedReconstitute Canister
Gas Blending ModuleDiluent Gas
InputDesorptionInterface
Sample Bag
MultiTraxController
Z-Head
Desorption Tube
Prototype Thermal Reconstitution System
Patent Pending
Sorbent Tube
Inert gas
Servo Drive
Inertized, Heat-tracedReconstitute Canister
Background Comparison: Tedlartm vs Metalized FEP
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Abundance
TIC: SBR018.D\data.msTIC: SBR017.D\data.ms (*)
18 HOUR Fill and Hold
Tedlartm
m-FEP
Phenol
DMAC
Phenol Response Precision Out of TedlarShort-term – Same Day
32.80.238.23
32.11.209.52
31.26.118.71
n%RSDSD(ppb)
Mean(ppb)
Series
Long-Term – 21 Day
%RSDMeanDay 21Day 14Day 7Day 17.18.68.29.58.78.2
Comparative Phenol Loss: Direct m-FEP Bag Versus Sorbent Tube; Freezer Stored & Reconstituted
X313434T=0+10 min
5448485150T=0+2.75 hr
22T=0+1.5 min
ReconstitutedDay 21
ReconstitutedDay 14
ReconstitutedDay 7
ReconstitutedDay 1
DirectDay 1
Time
75T=0+23 hr
Carthage Industrial Bottoms Area
Prototype, Low-Cost Field DDO Device
US Pat. #8,429,950 B2
Field DDO Device; Continuously Variable Dilution Ratio
US Pat. #8,429,950 B2
6 liter / min = 11:1 dilution ratio
16 liter / min = 8:1 dilution ratio
Prototype, Field DDO ‘Screening’ Device; Continuously Variable, Audible Alarmed
US Pat. #8,429,950 B2
Summary
Regardless of source, odor analysis is, first and foremost, chemical analysis; carrying the same constraints and limitations with respect to sample handling and storage.
While always carrying the ‘potential’ for extreme complexity, the odor response to real world odor sources is often remarkably simple; with both positive and negative impacts primarily driven by very small subsets of the total source emission. Sampling strategies should be biased toward those highest-impact odorants.
Regardless of surface treatment, extended storage of polar, high-impact semi-volatile odorants in the gas phase is ill-advised. An optimized whole-air odor sampling strategy is presented whereby odorants are field collected onto an adsorbent bed, shipped and stored under refrigeration in advance of gas phase reconstitution; just prior to analysis or composite sensory assessment.
Post-Phase ITransient Event Sampling
Strategy Development
Odor Cued ‘Beep-Ball’
Comparative Naphthalene Yields: m-FEP Gas Bag Grab Sample With Sorbent Tube Transfer
(MS SIM area count responses)
Indirect ‘Peak’ Series83,915 count Run #1
54,851 count Run #2
11X ‘Lull’69,383 count Average
Indirect Interim ‘Lull’
Run #1 6,216 count .07X ‘Peak’
Representative Odor Threshold Curves
Patent Pending
Sorbent Tube
Inert gas
Servo Drive
Inertized, Heat-tracedReconstitute Canister
Increasing Concentration
Incr
easi
ng o
d or
inte
n si ty
Odor Threshold
Recognition Threshold
Saturation Threshold
Annoyance Threshold
Higher Impact OdorantLower Impact Odorant
Odor Point-Source Prioritization
Utilizing Tracer Gas Injection
Integrated Multi Point-Source Transient Odor Event Generator System
Odorant / Tracer Pair Response Ratio Precision
5n8.56% RSD.082sd.96Mean
1.07Run #5.95Run #4.96Run #3.98Run #2.84Run #1
Naphth / CCl3 Response RatioRun Number
Transient Event Sampling with Tracer Gas Injection for Point-Source Prioritization (MS SIM area count responses)
DMBCCl3Naphthalene‘Mothball’ Event
2,487412,334486,227Mean480386,036584,887Run #3390650,217653,343 Run #2
6,592200,750220,450 Run #1
30,7822,88926,334Mean3,7712,98817,428Run #3
84,3735,58035,053Run #24,203<dl26,522Run #1DMBCCl3Naphthalene‘Bluebonnet’ Event