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Table 6 Five-state survey of air quality monitoring studies, unconventional oil and gas operations

From: Air concentrations of volatile compounds near oil and gas production: a community-based exploratory study

Agency (year) Target compound Sampling equipment Sample sites Duration Representative findings
ADEQ (2011) VOCs (total)
NO
NO2
PID (fixed)
PID (handheld)
4 compressor stations
6 drilling sites
3 well sites (fracking)
1 upwind
1 d (4–6 hrs.) VOCs “almost always below or near detection limits”
VOCs at drilling sites elevated (ave. 38–678 ppb; max. 350–5,321 ppb)
NO/NO2 rarely exceed detection limits
CDPHE (2012) NMOCs (78)
Methane
Canister 1 well pad (Erie) 3 wks. Detects = 42 of 78 compounds in >75% of samples
Benzene “well within EPA’s acceptable cancer risk range”
Acute and chronic HQs “well below” 1
CDPHE (2009) NMOCs (78)
VOCs
PM2.5
Canister
PID (handheld)
Filter (handheld)
8 wells (4 drilling, 4 completion) 1 d Total NMOC ave. 273 – 8,761 ppb at 8 sites
Total VOC ave. 6–3,023 ppb at 8 sites
PM2.5 ave. 7.3 - 16.7 μg/m3 at 8 sites
CDPHE, GCPHD (2007) VOCs (43)
PM10
Canister
Filter
14 sites
7 sites
24 mos. Detects = 15 of 43 compounds
Benzene ave. 28.2 μg/m3, max 180 μg/m3 (grab)
Toluene ave. 91.4 μg/m3, max 540 μg/m3 (grab)
CDPHE (2003–2012) NMOCs
Carbonyls
Canister 5 sites (2003)
6 sites (2006)
3+ sites (2012)
2 mos. Methane ave. 2,535 ppb (Platteville) vs. (1,780 ppb Denver)
Top NMOCs in Platteville = ethane, propane, butane
Benzene, toluene higher in Platteville
CDPHE (2002) VOCs (42)
SO2
NO, NO2
Canister
Continuous
2 well sites
1 residential
1 active flare
2 up-, down-valley
1 background
1 mo. Detects = 6 of 42 VOCs
Benzene in 6 of 20 (2.2-6.5 μg/m3)
Toluene in 18 of 20 (1.5-17 μg/m3)
OEPA (2014) VOCs (69)
VOCs
PM10/PM2.5
H2S
CO
Canister
GC/MS
Filter
1 well site
1 remote site
12 mos. Ongoing; data update provided in February 2014
Detects include BTEX, alkanes (e.g., ethane, hexane), H2S
Second site planned near processing plant
PA DEP (2010) VOCs (48)
Alkanes
Leak detection
Canister
OP-FTIR
GC/MS
FLIR
2 compressor stations
1 condensate tank
1 wastewater impoundment
1 background
5 wks. Detects include methane, ethane, propane, benzene (max. 758 ppb)
No conc.’s “that would likely trigger air-related health issues”
Fugitive gas stream emissions
PA DEP (2011) VOCs (48)
Alkanes
Leak detection
Canister
OP-FTIR
GC/MS
FLIR
2 compressor stations
1 completed well
1 well site (fracking)
1 well (tanks, separator)
1 background
4 wks. Detects include BTEX (benzene max. 400 ppb), methylbenzenes
No conc.’s “that would likely trigger air-related health issues”
Fugitive emissions from condensate tanks, piping
PA DEP (2011) VOCs (48)
Alkanes
Canister
OP-FTIR
GC/MS
2 compressor stations
1 well site (flaring)
1 well site (drilling)
1 background
4 wks. Detects include benzene (max. 400 ppb), toluene, ethylbenzene
Natural gas constituent detects near compressor stations
Conc.’s “do not indicate a potential for major air-related health issues”
PA DEP (2012) Criteria
VOCs/HAPs
Methane
H2S
“Full suite” 1 gas processing
2 large compressor stations
1 background
12 mos. Ongoing; report due in 2014
WDEQ (2013) VOCs/NMHCs
Ozone
Methane
NO, NO2
PM10/PM2.5
Canister
UV Photometric
FID
Chemiluminescence
Beta Attenuation
7 permanent stations (e.g., Boulder, Juel Spring, Moxa)
3 mesonet stations (Mesa, Paradise Warbonnet)
2 mobile trailer locations (Big Piney, Jonah Field)
Ongoing WDEQ mobile monitors placed at locations w/ oil & gas development
Mini-SODAR also placed adjacent to Boulder permanent station
“Relatively low concentrations” of VOCs found in canister samples
VOCs “consistently higher” at Paradise site (near oil & gas sources)
  1. BTEX = benzene, toluene, ethylbenzene, and xylenes; FID = flame ionization detector; FLIR = forward looking infrared; GC/MS = gas chromatography/mass spectrometry; HAP = hazardous air pollutant; NAAQS = National Ambient Air Quality Standard; NMHC = non-methane hydrocarbon; NMOC = non-methane organic compound; OP-FTIR = open-path Fourier transform infrared; PID = photoionization detector; VOC = volatile organic compound.