DOI: 10.5061/dryad.djh9w0wc5
title: CORNCOB (Characterizing Oil & gas & agRicultural emissions in the Northern COlorado Basin)

description: 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
description: **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](mailto:Emily.V.Fischer@colostate.edu); 970-491-8587 We recommend contacting Emily V. Fischer ([Emily.V.Fischer@colostate.edu](mailto: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 | 
 
 **File Name: 2025-08-06_CO_CAFOs.xlsx** | 
 
 | 
 
 | 
 
 | | :----------------- | :----------- |
 :-------------------------------------------------------------------------------------- | | **Variable Name** | **Units** | **Description** | | AG ID | - | Facility ID | | Permit Name | - | Facility Name | | Address | - | Facility Address | | Lat | degrees | Facility latitude | | Long | degrees | Facility longitude | | Permit Type | - | Registered or General Permitted CAFO | | Status | - | Facility Status | | County | - | County the facility is located within | | Primary Livestock | - | Primary CAFO livestock | | Maximum capacity | Head count | Maximum number of animals permitted | | Total animal units | Animal units | Conversion of animal head count based on animal size relative to a standard beef cattle | 
 
 **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 &lt;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 &gt;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 &gt;
 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](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 &lt;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](https://doi.org/10.1016/j.atmosenv.2023.120187)