CORNCOB (Characterizing Oil & gas & agRicultural emissions in the Northern COlorado Basin)

Fischer, Emily1 ; Cossel, Kevin2; Lill, Emily 1 ; Davis, Matthew1

Published Jul 16, 2025 on Dryad. https://doi.org/10.5061/dryad.djh9w0wc5

Data files

Jul 16, 2025 version files 65.97 MB

20250409_Weld_County_PT_Canisters.xlsx
13.28 KB
mobile_lab_drive_data.zip
10.59 MB
mobile_lab_stationary_data.zip
55.35 MB
README.md
16.89 KB

Abstract

This dataset was collected by Colorado State University (CSU) and the National Institute of Standards and Technology (NIST). Measurements of various trace gases in Northern Colorado were collected to understand the proportion of methane present in the atmosphere that is associated with animal husbandry versus oil and gas operations. A mobile lab was used to measure methane and ammonia levels downwind of large sources, and to identify how these mixing ratios change with the distance from a source

Title: CORNCOB (Characterizing Oil & gas & agRicultural emissions in the Northern COlorado Basin)

Funding: This work was supported by the Colorado Department of Public Health and Environment (CDPHE).

Keywords: volatile organic compounds (VOCs), triggered events, integrated samples, whole air samples, Northern Colorado, air quality, air monitoring, air pollution, community-based research

Spatial Coverage: Northern Colorado: multiple locations and mobile measurements.

Temporal Coverage: 8 March 2025 - 9 April 2025

Publications: None as of June 2025

**Data contact: **

Emily V. Fischer, Associate Professor, Department of Atmospheric Science. Emily.V.Fischer@colostate.edu; 970-491-8587

We recommend contacting Emily V. Fischer (Emily.V.Fischer@colostate.edu) for further guidance on using these datasets.

Definitions:

ppmv: Parts per million volume

ppbv: Parts per billion volume

TILDAS: CSU-owned, Quantum Cascade Tunable Infrared Laser Direct Absorption Spectrometer (QC-TILDAS) manufactured by Aerodyne Research Inc.

AERIS: Mid‑Infrared Analyzer Leak Detection System Mobile Methane/Ethane Analyzer manufactured by Aeris Technologies

CALTOPO: Real-time, mobile application for GPS tracking
Picarro: Picarro G1301 gas concentration analyzer
LOD: limit of detection

SLPM: Standard liter per minute

Data Description

This dataset contains information on various trace gases, meteorological conditions, and location collected on the NIST mobile lab around Northern Colorado from 8 March 2025 to 9 April 2025, as well as stationary data collected at the CSU Foothills Campus (40.589496° N, 105.153162° W) from 9 March 2025 to 11 March 2025 and the CSU Agricultural Research, Development and Education Center (ARDEC) (40.657929° N, 104.995094° W) from 20 March 2025 to 9 April 2025. Whole air canister samples were collected on 9 April 2025 near Galeton, CO following a loss of containment incident at the nearby Bishop oil and natural gas well (40.505181° N, 104.585317° W). The dataset includes 3 different files: 1) mobile_lab_drive_data.zip; 2) mobile_lab_stationary_data.zip; and 3) 20250409_Weld County_PT Canisters.xlsx. In each of the files, “-9999” indicates that there is no data for that time stamp. Reasons for no data being available for a time stamp include the instrument not collecting data at that time or the data being invalid. The following describes each of these files:

● mobile_lab_drive_data.zip

Zipped folder containing comma-delimited CSV files for each individual drive. Each file contains 20 columns
Data has been time-aligned to TILDAS NH3 data

● mobile_lab_stationary_data.zip

Zipped folder containing two zipped location-specific subfolders with daily comma-delimited CSV files. Each file contains 17 columns.
Subfolders are named foothills_campus_mobile_lab_stationary_data.zip and ardec_mobile_lab_stationary_data.zip
This data has not been time-aligned

● 20250409_Weld County_PT Canisters.xlsx

.xlsx file quantifying 52 VOCs

Variable information:

File Name: mobile_lab_drive_data.zip

Variable Name	Units	Description
datetime	MM/DD/YYYY HH:MM:SS	UTC date time (24-hour)
TILDAS_NH3_ppb	ppbv	Ammonia mixing ratio
AERIS_CH4_ppm	ppmv	AERIS methane mixing ratio
AERIS_C2H6_ppb	ppbv	AERIS ethane Mixing Ratio
AERIS_H2O_ppm	ppmv	AERIS water vapor mixing ratio
CALTOPO_lat	Degrees north	CALTOPO latitude
CALTOPO_lon	Degrees east	CALTOPO Longitude
van_spd_m/s	Meters per second	Van speed
wdir_degrees	Degrees relative to van	Wind direction
wdir_corr_degrees	Degrees true north	Motion-corrected wind direction
temp_C	Degrees celsius	Temperature
van_heading_degrees	Degrees true north	GPS_derived heading
rh_%	Percent	Relative Humidity
dewpoint_C	Degrees Celsius	Dewpoint
pressure_mbar	Millibars	Pressure
wspd_corr_m/s	Meters per second	Motion-corrected wind speed
wspd_m/s	Meters per second	Wind Speed
picarro_CO2_ppm	ppmv	Picarro carbon dioxide mixing ratio
picarro_CH4_ppm	ppmv	Picarro methane mixing ratio
picarro_h2o_ppm	ppmv	Picarro water vapor mixing ratio

File Name: mobile_lab_stationary_data.zip

Variable Name	Units	Description
datetime	MM/DD/YYYY HH:MM:SS	UTC date time (24-hour)
TILDAS_NH3_ppb	ppbv	Ammonia mixing ratio
AERIS_CH4_ppm	ppmv	AERIS methane mixing ratio
AERIS_C2H6_ppb	ppbv	AERIS ethane Mixing Ratio
AERIS_H2O_ppm	ppmv	AERIS water vapor mixing ratio
wdir_degrees	Degrees relative to van	Wind direction
wdir_corr_degrees	Degrees true north	Motion-corrected wind direction
temp_C	Degrees celsius	Temperature
van_heading_degrees	Degrees true north	GPS_derived heading
rh_%	Percent	Relative Humidity
dewpoint_C	Degrees Celsius	Dewpoint
pressure_mbar	Millibars	Pressure
wspd_corr_m/s	Meters per second	Motion-corrected wind speed
wspd_m/s	Meters per second	Wind Speed
picarro_CO2_ppm	ppmv	Picarro carbon dioxide mixing ratio
picarro_CH4_ppm	ppmv	Picarro methane mixing ratio
picarro_h2o_ppm	ppmv	Picarro water vapor mixing ratio

File Name: 20250409_Weld_County_PT_Canisters.xlsx

Variable Name	Units	Description
Sample ID	String	Long-name description
Canister #	String	Short-name description
Datetime (local)	YYYY/MM/DD HH:MM:SS	Local Time (MDT, 24-hour)
Latitude	Decimal degrees	Degrees North
Longitude	Decimal Degrees	Degrees East
Note	String	Short location description
ethane	ppbv	Ethane mixing ratio
Ethene	ppbv	Ethene mixing ratio
Propane	ppbv	Propane mixing ratio
Propene	ppbv	Propene mixing ratio
i-Butane	ppbv	i-Butane mixing ratio
n-Butane	ppbv	n-Butane mixing ratio
Ethyne	ppbv	Ethyne mixing ratio
1-Butene	ppbv	1-Butene mixing ratio
t-2-Butene	ppbv	t-2-Butene mixing ratio
c-2-Butene	ppbv	c-2-Butene mixing ratio
Cyclopentane	ppbv	Cyclopentane mixing ratio
i-pentane	ppbv	i-pentane mixing ratio
n-Pentane	ppbv	n-Pentane mixing ratio
t-2-Pentene	ppbv	t-2-Pentene mixing ratio
1-Pentene	ppbv	1-Pentene mixing ratio
cis-2-Pentene	ppbv	cis-2-Pentene mixing ratio
n-Hexane	ppbv	n-Hexane mixing ratio
Isoprene	ppbv	Isoprene mixing ratio
2,4-Dimethylpentane	ppbv	2,4-Dimethylpentane mixing ratio
n-Heptane	ppbv	n-Heptane mixing ratio
Benzene	ppbv	Benzene mixing ratio
cyclohexane	ppbv	Cyclohexane mixing ratio
2,3-Dimethyl Pentane	ppbv	2,3-Dimethyl Pentane mixing ratio
2-methylhexane	ppbv	2-methylhexane mixing ratio
3-methylhexane	ppbv	3-methylhexane mixing ratio
2,2,4-Trimethyl Pentane	ppbv	2,2,4-Trimethyl Pentane mixing ratio
Methylcyclohexane	ppbv	Methylcyclohexane mixing ratio
2,3,4 Trimethyl Pentane	ppbv	2,3,4 Trimethyl Pentane mixing ratio
Toluene	ppbv	Toluene mixing ratio
2-methylheptane	ppbv	2-methylheptane mixing ratio
3-methylheptane	ppbv	3-methylheptane mixing ratio
n-octane	ppbv	n-octane mixing ratio
Ethylbenzene	ppbv	Ethylbenzene mixing ratio
m+p-xylene	ppbv	m+p-xylene mixing ratio
Styrene	ppbv	Styrene mixing ratio
o-xylene	ppbv	o-xylene mixing ratio
n-nonane	ppbv	n-nonane mixing ratio
I-propylbenzene	ppbv	I-propylbenzene mixing ratio
n-propylbenzene	ppbv	n-propylbenzene mixing ratio
3-ethyltoluene	ppbv	3-ethyltoluene mixing ratio
4-ethyltoluene	ppbv	4-ethyltoluene mixing ratio
1,3,5-trimethylbenzene	ppbv	1,3,5-trimethylbenzene mixing ratio
2-ethyltoluene	ppbv	2-ethyltoluene mixing ratio
1,2,4-trimethylbenzene	ppbv	1,2,4-trimethylbenzene mixing ratio
n-decane	ppbv	n-decane mixing ratio
1,2,3-trimethylbenzene	ppbv	1,2,3-trimethylbenzene mixing ratio
1,3-diethylbenzene	ppbv	1,3-diethylbenzene mixing ratio
1,4-diethylbenzene	ppbv	1,4-diethylbenzene mixing ratio
C2HCl3	ppbv	C2HCl3 mixing ratio
C2Cl4	ppbv	C2Cl4 mixing ratio
acetonitrile	ppbv	Acetonitrile mixing ratio
methane	ppmv	Methane mixing ratio

Environmental or experimental conditions:

The instrumentation was located inside the NIST mobile lab with a shared inlet that extended outside the van. At the foothills campus stationary location, the van was located next to a satellite building, away from parking lots and roadways. At the ARDEC location, the van was located near multiple livestock pens.

Uncertainty of measurements:

Compound	Uncertainty (%)	LOD	LOD_unit	Data _unit
TILDAS NH3	12	200	pptv	ppbv
AERIS CH4	11	1	ppmv	ppmv
AERIS C2H6	18	500	pptv	ppbv
AERIS H2O	6	20	ppmv	ppmv
Picarro CO2	12	10	ppmv	ppmv
Picarro CH4	12	25	ppbv	ppmv
Picarro H2O	8	30	ppmv	ppmv
GC Methane	4	0.21	ppmv	ppmv
GC C2 - C10 NMHCs	2 – 18	0.001 – 0.010	ppbv	ppbv
GC C2 halocarbons	14 – 20	0.001 – 0.010	ppbv	ppbv

Standards, calibrations, and quality controls:

The NH3 TILDAS was calibrated after the field campaign using an NH3 permeation tube (Kin-Tek Analytical, Part Number: EL-SRT-2-000.50-2003/30) held at constant temperature with a constant flow of N2. Zeros were manually triggered during each drive using an ultra-zero air cylinder.

The AERIS C2H6/CH4 instrument was calibrated before and after the field campaign using a mixed 10 ppm CH4, 1 ppm C2H6 standard cylinder. Calibration points and zeros were manually triggered during drives using the calibration cylinder and an ultra-zero air cylinder.

The CO2/CH4 Picarro used previous calibrations of the instrument. For CO2 and CH4, a quadratic water correction was performed first using measurements at 12 different humidity levels. An additional linear correction was done to scale the dry values to the WMO scale based on measurements of 6 different calibration tanks. The water was independently calibrated previously using a chilled mirror hygrometer. The CO2 and CH4 calibrations have been found to be very stable and were checked against WMO standards before and after the campaign.

The NH3 TILDAS used a 9 ft long teflon inlet line with a 1/4” outer diameter and 1/8” inner diameter. The inlet was inside a 3/8” copper tube that was wrapped with electrical heating tape (BriskHeat # RKP1B0240) heated to 49°C. The residence time in the TILDAS inlet line was <1 second with a flow rate of 5.78 SLPM. The NH3 TILDAS utilized an inertial inlet (5.78 SLPM) for filterless separation of particles >300nm from the sample stream. The inertial inlet consisted of a quartz tube (12.7 mm outer diameter, 10.4 mm inner diameter) with an integral critical orifice ~1 mm in diameter. After passing through the orifice, the sample flow enters a second quartz tube (25.2 mm outer diameter, 22.2 mm inner diameter) that is sleeved around the 12.7 mm tube. The flow through the critical orifice is forced to make a 180-degree turn, with the inertia of particles > 300 nm being too great to follow the gas stream. The inertial inlet was located in an enclosure maintained at 40°C. More information on the inertial inlet can be found in Pollack et al. (2019). https://doi.org/10.5194/amt-12-3717-2019 The AERIS C2H6/CH4, and CO2/CH4 Picarro shared a 9 ft teflon inlet line with a 1/4” outer diameter and 1/8” inner diameter. The residence time was <4 seconds. The flow rate of the AERIS C2H6/CH4 instrument was 665 SCCM, and the flow rate of the CO2/CH4 Picarro was ~300 SCCM. Both inlet lines were joined together at their tips to facilitate the addition of zero air. The zero air signal was used to time-align the instruments despite the differing residence time in each inlet.

The whole air samples were analyzed by GC, following the method described in Ku et al., 2024. https://doi.org/10.1016/j.atmosenv.2023.120187

CORNCOB (Characterizing Oil & gas & agRicultural emissions in the Northern COlorado Basin)

Data files

Abstract

README