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