In the Fall of 2010, the Central Park Area Neighbors Association (CPANA) Board of Directors responded to citizen concerns about the air quality effects of proposed gas drilling in Southern Lewisville by approving a study that would undertake some baseline readings of volatile organic compounds (VOCs) over the course of a full year. The study, which would hopefully (at the time) be concluded prior to the commencement of gas drilling activity would give an estimate of the amount of VOCs in the air before gas activity, in order to provide a basis for comparison after gas activity. Results Summary Most of the volatile organic compounds detected in this study were picked up in quantities less than 0.1 parts per billion (ppb). The highest maximum concentration of any substance was only 0.49 ppb. The highest concentration for benzene in any given month was 0.27 ppb, well below the 1.4 ppb long-term effects screening level (LTESL) established by the Texas Commission on Environmental Quality (TCEQ). The highest monthly VOC load for any given sample was 1.81 ppb for all substances detected, and averaged only 0.82 ppb. Although the levels detected were very low, the data suggest a difference between the two general areas being surveyed, with one area showing about twice the VOC load. In any case, no compounds came close to any air monitoring comparison values (AMCVs). Methodology Chosen Other studies conducted around the Barnett shale typically used summa canisters for this, taking a sample anywhere from 30 minutes to 24 hours. Not only are these tests prohibitively expensive for the type of study CPANA could afford, but they are hardly representative of the dynamic nature of wind and the effects of weather, season, and temperature as they vary over time. Some VOCs may occur naturally, and be seasonal based on flora and fauna, so we thought it best to get samples that would show a picture of what it looks like over the course of a year. The sampling method CPANA chose was the passive diffusion tube. Stainless steel tubes containing a specially chosen sorbent material were placed at the sampling locations and left open to the air for periods averaging about a month each. As ambient air diffuses up the tubes, the sorbent material locks in the contaminants. The tubes are then sent to the laboratory for analysis using Thermal Desorption - Gas Chromatography / Mass Spectrometry (TD-GC/MS) In this process, the tubes are heated to force the sorbent to release the contaminants into a specialized machine that determines the compounds and approximate concentrations on the tube. Using a formula for the amount of air that diffuses into the tube over the time period exposed, the approximate average concentration in the air over the sampling period is calculated. Laboratory CPANA utilized Ormantine USA, Ltd., an analytical laboratory company to supply the tubes and do the analysis on them after exposure. Ormantine was chosen because of their product and method, and because they have no ties to any of the local gas operators. Ormantine is affiliated with Gradko Environmental, a UKAS accredited laboratory in England. Gradko supplies the pre-conditioned diffusion tubes, and analyzes them after exposure. Gradko's accreditation applies only to the methods they use to determine the mass of the analytes on the tubes, and not to the parts-per-billion figures calculated based on that mass. Analytes CPANA Baseline VOC Study CPANA Baseline VOC Study Page 1
Baseline study of VOCs in the ambient air in Lewisville Texas, conducted for over a year from June 2010 - July 2011 by the Central Park Area Neighbors Association
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In the Fall of 2010, the Central Park Area Neighbors Association (CPANA) Board of Directors
responded to citizen concerns about the air quality effects of proposed gas drilling in
Southern Lewisville by approving a study that would undertake some baseline readings of
volatile organic compounds (VOCs) over the course of a full year. The study, which would
hopefully (at the time) be concluded prior to the commencement of gas drilling activity
would give an estimate of the amount of VOCs in the air before gas activity, in order to
provide a basis for comparison after gas activity.
Results SummaryMost of the volatile organic compounds detected in this study were picked up in quantities
less than 0.1 parts per billion (ppb). The highest maximum concentration of any substance
was only 0.49 ppb. The highest concentration for benzene in any given month was 0.27 ppb,
well below the 1.4 ppb long-term effects screening level (LTESL) established by the Texas
Commission on Environmental Quality (TCEQ). The highest monthly VOC load for any given
sample was 1.81 ppb for all substances detected, and averaged only 0.82 ppb. Although the
levels detected were very low, the data suggest a difference between the two general areas
being surveyed, with one area showing about twice the VOC load. In any case, no
compounds came close to any air monitoring comparison values (AMCVs).
Methodology ChosenOther studies conducted around the Barnett shale typically used summa canisters for this,
taking a sample anywhere from 30 minutes to 24 hours. Not only are these tests
prohibitively expensive for the type of study CPANA could afford, but they are hardly
representative of the dynamic nature of wind and the effects of weather, season, and
temperature as they vary over time. Some VOCs may occur naturally, and be seasonal based
on flora and fauna, so we thought it best to get samples that would show a picture of what it
looks like over the course of a year.
The sampling method CPANA chose was the passive diffusion tube. Stainless steel tubes
containing a specially chosen sorbent material were placed at the sampling locations and left
open to the air for periods averaging about a month each. As ambient air diffuses up the
tubes, the sorbent material locks in the contaminants. The tubes are then sent to the
laboratory for analysis using Thermal Desorption - Gas Chromatography / Mass Spectrometry
(TD-GC/MS) In this process, the tubes are heated to force the sorbent to release the
contaminants into a specialized machine that determines the compounds and approximate
concentrations on the tube. Using a formula for the amount of air that diffuses into the tube
over the time period exposed, the approximate average concentration in the air over the
sampling period is calculated.
LaboratoryCPANA utilized Ormantine USA, Ltd., an analytical laboratory company to supply the tubes
and do the analysis on them after exposure. Ormantine was chosen because of their
product and method, and because they have no ties to any of the local gas operators.
Ormantine is affiliated with Gradko Environmental, a UKAS accredited laboratory in England.
Gradko supplies the pre-conditioned diffusion tubes, and analyzes them after exposure.
Gradko's accreditation applies only to the methods they use to determine the mass of the
analytes on the tubes, and not to the parts-per-billion figures calculated based on that mass.
Analytes
CPANA Baseline VOC Study
CPANA Baseline VOC Study Page 1
AnalytesThis study is concerned with VOCs only. Because benzene was a major concern with gas-
related activities in other communities, CPANA wanted a quantitative analysis of benzene
with each sample. In order to get a feel for the other possible compounds in the air, we
asked Ormantine to provide the top nine other compounds (semi-quantitatively, based on
toluene standards) with each sample.
Wind DirectionWind direction and speed measurements were not taken due to the length of the study.
However, wind speed and directional averages for our area are attached. The wind rose
data is from 1984 - 1992, so it is possible that there is an updated version somewhere that
would account for any climate change since then.
Accurate day-by-day wind speed and directional info is available from the TCEQ air
*Blank is a trip blank, held unexposed while an identical tube was exposed in the field. Trip blank is sent back to the lab as if it's an actual sample, and the lab doesn't know in advance.
Witnesses:
Placement Retrieval
Steve Southwell, CPANA Board MemberAnne McMahon, CPANA Board MemberR.Neil Ferguson, LNRUD PresidentDarrell Patterson, CPANA Board Member
CPANA Sampling Locations
For the purpose of the benchmark air quality study, CPANA chose locations within its constituent area in Southern Lewisville that it felt represented a possible worst case scenario for any future emissions from natural gas drilling
Because our sampling is done passively through an unattended device, and CPANA desires to keep the locations of these devices secure to avoid tampering, we have listed on this sheet only general areas in which we've placed our boxes. Each box has a number, and that box number is unique to a fixed location, which does not change from
This map shows the approximate locations of our sampling boxes.
Exact locations of the samples will be disclosed to appropriate governmental entities in the event that investigation is necessary, or upon the end of our testing.
Box 210: East of Valley Parkway, North of Corporate Drive, West of Regency Drive, South of Timber Creek.Box 185: East of Valley Parkway, South of Corporate Drive, West of Briarcliff, North of Holly Lane.Box 99: Within 500 feet of the proposed B&H well site on Southwest Parkway, West of S.H. 121 Business.
Notes:Light Blue BTEX Compounds - Benzene, Toluene, Xylene, EthylbenzeneBlank Not in the top 9 compounds other than benzene detected for that sample
<LOD = Analyzed for, but below limits of detection. Iso = The compound is shown elsewhere as a different isomer, or non-specific isomer group.Average* when detected.
Samples - results in ppb
Isopropyl AlcoholCyclohexane, isothiocyanato-
DodecaneCyclohexane, isocyanato-
Acetic AcidToluene
Cyclohexanone
TridecaneBenzene
Undecane1R-alpha-pinene
Benzene, 1,2,3-trimethyl-
Benzene, 1,2,4-trimethyl-Butane
p-Xylene
HexadecanePhenol
m/p-XyleneDichlorodifluoromethane
OctadecaneOctane
HeptadecaneButane, 2-methyl
Heptane
Total VOC Loads (ppb)
EthylbenzeneCyclohexane, methyl
DecaneIsobutane
Benzothiazole
Heptane, 2,2,4,6,6-pentamethylCarbon Disulfide
AcetonePentane, 2-methyl
Ethanol
Hexane, 3 Methyl
o-XyleneTetradecane
1,4-Methanoazulene, decahydro-4,8,8Pentadecane
2,3,4-trimethylpentaneHexane
Volatile Organic Compounds - CPANA Baseline Study
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
1 2 3 4 5 6 7 8 9a 9b 10a 10b 11
Sample Number
Part
s pe
r bill
ion
Total VOC LoadsBenzeneToluene
Technical Data Sheet: TDS 8 VOLATILE ORGANIC COMPOUNDS (VOCs) Passive Sampler and Active (pumped) Sampler Tubes This tube is designed for passive (time weighted average concentrations) and active (pumped) sampling of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) in the carbon range of C2 – C32. The tube can be used passively for time weighted average concentrations, or pumped (active) for indoor and outdoor monitoring, or for workplace monitoring and comparison to health and safety workplace exposure limits.
Description: Stainless steel tube filled with a solid polymer absorbent and two brass swagelock caps. For passive sampling an aluminium air diffuser is supplied (attached to bottom of tube in above photograph) which is fitted to the sampling end of the tube (groove end) during exposure, by replacing the brass nut. For active sampling, both brass nuts are removed, and an air pump set to 50 ml/min, is connected to the non-sampling end (non-groove end) of the tube and run for a preset period. Suitable for carrying out spatial or localized assessments of volatile and semi-volatile organics in ambient air, soil, workplace, or industrial monitoring. Can be used for measuring VOCs and SVOCs in soil using a borehole or a soil probe (see Technical Sheet TDS 11). Tube Dimensions: 6.3mm OD x 5.0mm ID x 90mm length. An appropriate sorbent is selected to suit the application required (See Page 2, below). Concentrations absorbed by the tube are measured by thermal desorption and analysis by Gas Chromatography with Flame Ionization Detection (GC/FID) or by Gas Chromatography/Mass Spectroscopy (GC/MS). Both methods are U.K.A.S. accredited. Recommended Exposure Periods for Passive Sampling: 1–4 weeks. For Active Sampling the safe sampling volumes for each type of compound to be monitored should be considered (published figures). Uptake Rates: Determined by calibration in a standard atmosphere or quoted from published data. Air Velocity: Tube fitted with filter therefore negligible influence. Storage: Store in a dark, cool environment free from residual airborne VOC. Shelf Life: 12 weeks from conditioning date dependant on type of solid sorbent used. Desorption Efficiency: d = 0.99 (determined using N.I.S.T. Standard Analytes). Analytical Expanded Measurement Uncertainty: +/- 14.8%. Limit of Detection (LOD: Analysis): 0.2 ppb.
• Ambient Air Monitoring of Traffic Systems, Factory Outputs such as Paint Shops, Petrochemical Boundaries. • Stack monitoring. • Workplace monitoring: Measuring levels of airborne solvent vapors. • Personal Monitoring • Soil Monitoring • Measurement of Occupational Exposure Levels • Biological Monitoring i.e. Non-invasive measuring of levels of VOCs taken into the
body by skin adsorption, ingestion and inhalation. This method provides vital information on the potentially harmful build-up of chemicals in the body after prolonged low-level exposure.
Packaging Of Sorbents: Each type of sorbent is packed into the thermal desorption tube under strict quality control and under laboratory environment conditions. The weight of the sorbent packed is controlled to within +/- 5%. Selection of Absorbents: The choice of absorbent depends on the volatility of the analyte concerned. Sorbents or series of sorbents selected must quantitatively retain the compounds from the volume of air/gas sampled and then be released as efficiently as possible when the tube is desorbed. A general rule is to use the boiling point of the component as a guide to its volatility. The more volatile the analyte, the stronger the sorbent must be. For further information, please contact our Technical Dept at Ormantine USA Ltd. Inc. Tel. 321 676 7003 Fax. 321 676 7699 E-Mail : sales @ormantineusa.com