Volatile organic compound emissions from the oil and natural gas industry in the Uintah Basin, Utah: Oil and gas well pad emissions compared to ambient air composition

Emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uintah Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aromatics, alkanes, cycloalkanes and methanol were observed for extended periods of time and for short-term spikes caused by local point sources. The mixing ratios during the time the mobile laboratory spent on the well pads were averaged. High mixing ratios were found close to all point sources, but gas well pads with collection and dehydration on the well pad were clearly associated with higher mixing ratios than other wells. The comparison of the VOC composition of the emissions from the oil and natural gas well pads showed that gas well pads without dehydration on the well pad compared well with the majority of the data at Horse Pool, and that oil well pads compared well with the rest of the ground site data. Oil well pads on average emit heavier compounds than gas well pads. The mobile laboratory measurements confirm the results from an emissions inventory: the main VOC source categories from individual point sources are dehydrators, oil and condensate tank flashing and pneumatic devices and pumps. Raw natural gas is emitted from the pneumatic devices and pumps and heavier VOC mixes from the tank flashings

Instrumentation and Measurement Strategy for the NOAA SENEX Aircraft Campaign as Part of the Southeast Atmosphere Study 2013

Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeast of the US. In addition, anthropogenic emissions are significant in the Southeast US and summertime photochemistry is rapid. The NOAA-led SENEX (Southeast Nexus) aircraft campaign was one of the major components of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. Here we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign. The aircraft, its capabilities and standard measurements are described. The instrument payload is summarized including detection limits, accuracy, precision and time resolutions for all gas-and-aerosol phase instruments. The inter-comparisons of compounds measured with multiple instruments on the NOAA WP-3D are presented and were all within the stated uncertainties, except two of the three NO2 measurements. The SENEX flights included day- and nighttime flights in the Southeast as well as flights over areas with intense shale gas extraction (Marcellus, Fayetteville and Haynesville shale). We present one example flight on 16 June 2013, which was a daytime flight over the Atlanta region, where several crosswind transects of plumes from the city and nearby point sources, such as power plants, paper mills and landfills, were flown. The area around Atlanta has large biogenic isoprene emissions, which provided an excellent case for studying the interactions between biogenic and anthropogenic emissions. In this example flight, chemistry in and outside the Atlanta plumes was observed for several hours after emission. The analysis of this flight showcases the strategies implemented to answer some of the main SENEX science questions

Observation and modeling of the evolution of Texas power plant plumes

During the second Texas Air Quality Study 2006 (TexAQS II), a full range of pollutants was measured by aircraft in eastern Texas during successive transects of power plant plumes (PPPs). A regional photochemical model is applied to simulate the physical and chemical evolution of the plumes. The observations reveal that SO2 and NOy were rapidly removed from PPPs on a cloudy day but not on the cloud-free days, indicating efficient aqueous processing of these compounds in clouds. The model reasonably represents observed NOx oxidation and PAN formation in the plumes, but fails to capture the rapid loss of SO2 (0.37 h−1) and NOy (0.24 h−1) in some plumes on the cloudy day. Adjustments to the cloud liquid water content (QC) and the default metal concentrations in the cloud module could explain some of the SO2 loss. However, NOy in the model was insensitive to QC. These findings highlight cloud processing as a major challenge to atmospheric models. Model-based estimates of ozone production efficiency (OPE) in PPPs are 20–50 % lower than observation-based estimates for the cloudy day

Evaluation of GOME Satellite Measurements of Tropospheric NO2 and HCHO using Regional Data from Aircraft Campaigns in the Southeastern United States

We compare tropospheric measurements of nitrogen dioxide (NO2) and formaldehyde (HCHO) from the Global Ozone Monitoring Experiment (GOME) satellite instrument with in situ measurements over eastern Texas and the southeast United States. On aveiage, the GOME and in situ measurements of tropospheric NO2 and HCHO columns are consistent despite pronounced sampling differences. The geometric mean in situ to GOME ratios over the campaign are 1.08 for NO2 and 0.84 for HCHO, with corresponding geometric standard deviations of 1.27 and 1.38. The correlation of the observed column spatial variability between the two NO2 measurement sets is encouraging before (r2 = 0.54, n = 18) and after (r2 = 0.67, n = 18) correcting for a sampling bias. Mean relative vertical profiles of HCHO and NO2 calculated with a global three-dimensional model (GEOS-CHEM) and used in the GOME retrieval are highly consistent with in situ measurements; differences would affect the retrieved NO2 and HCHO columns by a few percent. GOME HCHO columns over eastern Texas include contributions from anthropogenic volatile organic compound (VOC) emissions but are dominated by biogenic VOC emissions at the regional scale in August-September when HCHO columns are within 20% of those over the southeastern United States. In situ measurements show that during summer the lowest 1500 m (the lower mixed layer) contains 75% of the tropospheric NO2 column over Houston and Nashville, and 60% of the HCHO column over Houston. Future validation of space-based measurements of tropospheric NO2 and HCHO columns over polluted regions should include coincident in situ measurements that span the entire satellite footprint, especially in the heterogeneous mixed layer

Summary of Results from the NOAA Shale Oil and Natural Gas Nexus (SONGNEX) Study

In March and April of 2015, the NOAA WP-3D research aircraft made airborne measurements over several different oil and natural gas production regions in the central and western U.S. ranging from North Dakota to Texas. The study was conducted at a time when the domestic production of natural gas was at an all-time high and the production of crude oil near an all-time high, but also when drilling activity had abruptly decreased due to a drop in the price of oil. In this presentation, we will give a summary of the measurement results obtained in the different production regions. Emission fluxes of greenhouse gases (CH4) and air pollutants (VOCs, NOx, air toxics) were determined through mass balance and from enhancement ratios versus methane. While photochemistry was generally weak during the flights, some trace gases showed evidence for secondary formation. Measurements by mass spectrometry showed the presence of some less commonly observed trace gases including nitrogen heterocyclic compounds. Emissions of pollutants are expressed as a fraction of the produced natural gas and crude oil. Such metrics can be compared with emission factors for fossil fuel combustion by other sources (motor vehicles and power plants) and allow a comparison of emissions from different stages in the lifecycle of fossil fuels. We have also studied NOx emissions from oil and natural gas production through trend analysis of the NO2columns from the Ozone Monitoring Instrument. This analysis shows that the drilling of new wells and the extraction of crude oil and natural gas both lead to NOx emissions. These results are compared with a new fuel-based emission inventory for NOx emissions from oil and natural gas production

Reactive uptake coefficients for N2O5 determined from aircraft measuremnts during the Second Texas Air Quality Study: Comparison to current model parameterizations

This paper presents determinations of reactive uptake coefficients for N2O5, gamma( N2O5), on aerosols from nighttime aircraft measurements of ozone, nitrogen oxides, and aerosol surface area on the NOAA P-3 during Second Texas Air Quality Study (TexAQS II). Determinations based on both the steady state approximation for NO3 and N2O5 and a plume modeling approach yielded gamma(N2O5) substantially smaller than current parameterizations used for atmospheric modeling and generally in the range 0.5-6 x 10(-3). Dependence of gamma(N2O5) on variables such as relative humidity and aerosol composition was not apparent in the determinations, although there was considerable scatter in the data. Determinations were also inconsistent with current parameterizations of the rate coefficient for homogenous hydrolysis of N2O5 by water vapor, which may be as much as a factor of 10 too large. Nocturnal halogen activation via conversion of N2O5 to ClNO2 on chloride aerosol was not determinable from these data, although limits based on laboratory parameterizations and maximum nonrefractory aerosol chloride content showed that this chemistry could have been comparable to direct production of HNO3 in some cases

Summary of Results from the NOAA Shale Oil and Natural Gas Nexus (SONGNEX) Study

In March and April of 2015, the NOAA WP-3D research aircraft made airborne measurements over several different oil and natural gas production regions in the central and western U.S. ranging from North Dakota to Texas. The study was conducted at a time when the domestic production of natural gas was at an all-time high and the production of crude oil near an all-time high, but also when drilling activity had abruptly decreased due to a drop in the price of oil. In this presentation, we will give a summary of the measurement results obtained in the different production regions. Emission fluxes of greenhouse gases (CH4) and air pollutants (VOCs, NOx, air toxics) were determined through mass balance and from enhancement ratios versus methane. While photochemistry was generally weak during the flights, some trace gases showed evidence for secondary formation. Measurements by mass spectrometry showed the presence of some less commonly observed trace gases including nitrogen heterocyclic compounds. Emissions of pollutants are expressed as a fraction of the produced natural gas and crude oil. Such metrics can be compared with emission factors for fossil fuel combustion by other sources (motor vehicles and power plants) and allow a comparison of emissions from different stages in the lifecycle of fossil fuels. We have also studied NOx emissions from oil and natural gas production through trend analysis of the NO2columns from the Ozone Monitoring Instrument. This analysis shows that the drilling of new wells and the extraction of crude oil and natural gas both lead to NOx emissions. These results are compared with a new fuel-based emission inventory for NOx emissions from oil and natural gas production.Abstract A33C-04 presented at 2018 Fall Meeting, AGU, Washington, D.C., 10-14 Dec. Session: A33C Emissions of Atmospheric Pollutants from Oil, Gas, and Coal Operations IAtmospheric Remote Sensin

Observations of ozone transport from the free troposphere to the Los Angeles basin

Analysis of in situ airborne measurements from the CalNex 2010 field experiment (Research at the Nexus of Air Quality and Climate Change) show that ozone in the boundary layer over Southern California was increased by downward mixing of air from the free troposphere (FT). The chemical composition, origin, and transport of air upwind and over Los Angeles, California, were studied using measurements of carbon monoxide (CO), ozone, reactive nitrogen species, and meteorological parameters from the National Oceanic and Atmospheric Administration WP-3D aircraft on 18 research flights in California in May and June 2010. On six flights, multiple vertical profiles from 0.2-3.5 km above ground level were conducted throughout the Los Angeles (LA) basin and over the Pacific Ocean. Gas phase compounds measured in 32 vertical profiles are used to characterize air masses in the FT over the LA basin, with the aim of determining the source of increased ozone observed above the planetary boundary layer (PBL). Four primary air mass influences were observed regularly in the FT between approximately 1 and 3.5 km altitude: upper tropospheric air, long-range transport of emissions, aged regional emissions, and marine air. The first three air mass types accounted for 89% of the FT observations. Ozone averaged 71 ppbv in air influenced by the upper troposphere, 69 ppbv in air containing emissions transported long distances, and 65 ppbv in air with aged regional emissions. Correlations between ozone and CO, and ozone and nitric acid, demonstrate entrainment of ozone from the FT into the LA PBL. Downward transport of ozone-rich air from the FT into the PBL contributes to the ozone burden at the surface in this region and makes compliance with air quality standards challenging

Airborne Measurements of Ethene from Industrial Sources Using Laser Photo-Acoustic Spectroscopy

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