A5101692609- Atmospheric and Environmental Gas Dynamics
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Atmospheric chemistry and aerosols
- Hydrocarbon exploration and reservoir analysis
- Vehicle emissions and performance
- Reservoir Engineering and Simulation Methods
- Global Energy and Sustainability Research
- Methane Hydrates and Related Phenomena
- Oil, Gas, and Environmental Issues
- Carbon Dioxide Capture Technologies
- Energy, Environment, and Transportation Policies
- Noise Effects and Management
- Environmental Justice and Health Disparities
- Climate Change Policy and Economics
- CO2 Sequestration and Geologic Interactions
- Climate Change and Health Impacts
- Impact of Light on Environment and Health
- Integrated Energy Systems Optimization
- Coal Properties and Utilization
- Hydraulic Fracturing and Reservoir Analysis
- Advanced Chemical Sensor Technologies
- Wind and Air Flow Studies
- Petroleum Processing and Analysis
- Planetary Science and Exploration
Environmental Defense Fund
2012-2024
University of California, Berkeley
1993
Methane emissions from the U.S. oil and natural gas supply chain were estimated by using ground-based, facility-scale measurements validated with aircraft observations in areas accounting for ~30% of production. When scaled up nationally, our facility-based estimate 2015 is 13 ± 2 teragrams per year, equivalent to 2.3% gross This value ~60% higher than Environmental Protection Agency inventory estimate, likely because existing methods miss released during abnormal operating conditions. this...
Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse emissions in process. However, there has also been confusion about climate implications increased use natural for electric power transportation. We propose illustrate technology warming potentials robust transparent way to compare cumulative radiative forcing created alternative technologies fueled oil or coal using best available estimates from each cycle (i.e.,...
Using new satellite observations and atmospheric inverse modeling, we report methane emissions from the Permian Basin, which is among world's most prolific oil-producing regions accounts for >30% of total U.S. oil production. Based on measurements May 2018 to March 2019, natural gas production are estimated be 2.7 ± 0.5 Tg a-1, representing largest flux ever reported a oil/gas-producing region more than two times higher bottom-up inventory-based estimates. This magnitude 3.7% gross extracted...
Significance Past studies reporting divergent estimates of methane emissions from the natural gas supply chain have generated conflicting claims about full greenhouse footprint gas. Top-down based on large-scale atmospheric sampling often exceed bottom-up source-based emission inventories. In this work, we reconcile top-down and in one country’s major production basins using easily replicable measurement data integration techniques. These convergent provide greater confidence that can...
Abstract Effectively mitigating methane emissions from the natural gas supply chain requires addressing disproportionate influence of high-emitting sources. Here we use a Monte Carlo simulation to aggregate all components on production sites in Barnett Shale region (Texas). Our total emission estimates are two-thirds those derived independent site-based measurements. Although some operations occur by design (condensate flashing and liquid unloadings), they more than an order magnitude less...
Air pollution measurements collected through systematic mobile monitoring campaigns can provide outdoor concentration data at high spatial resolution. We explore approaches to minimize requirements for mapping a city's air quality using monitors with "data-only" versus predictive modeling approaches. equipped two Google Street View cars 1-Hz instruments collect nitric oxide (NO) and black carbon (BC) in Oakland, CA. strategies efficiently patterns Monte Carlo analyses. First, we approach...
Methane emissions from the oil and gas industry (O&G) other sources in Barnett Shale region were estimated by constructing a spatially resolved emission inventory. Eighteen source categories using multiple data sets, including new empirical measurements at regional O&G sites national study of gathering processing facilities. Spatially referenced activity compiled federal state databases combined with facility factors calculated Monte Carlo simulations that account for high representing very...
Emissions from natural gas production sites are characterized by skewed distributions, where a small percentage of sites—commonly labeled super-emitters—account for majority emissions. A better characterization super-emitters is needed to operationalize ways identify them and reduce We designed conceptual framework that functionally defines superemitting as those with the highest proportional loss rates (methane emitted relative methane produced). Using this concept, we estimated total...
Oil and gas (O&G) well pads with high hydrocarbon emission rates may disproportionally contribute to total methane volatile organic compound (VOC) emissions from the production sector. In turn, these be missing most bottom-up inventories. We performed helicopter-based infrared camera surveys of more than 8000 O&G in seven U.S. basins assess prevalence distribution high-emitting sources (detection threshold ∼ 1-3 g s(-1)). The proportion sites such was 4% nationally but ranged 1% Powder River...
Diverse urban air pollution sources contribute to spatially variable atmospheric concentrations, with important public health implications. Mobile monitoring shows promise for understanding spatial pollutant patterns, yet it is unclear whether uncertainties associated temporally sparse sampling and instrument performance limit our ability identify locations of elevated pollution. To address this question, we analyze 9 months repeated weekday daytime on-road mobile measurements black carbon...
ADVERTISEMENT RETURN TO ISSUEPREVViewpointNEXTUsing Multi-Scale Measurements to Improve Methane Emission Estimates from Oil and Gas Operations in the Barnett Shale Region, TexasRobert Harriss*, Ramón A. Alvarez, David Lyon, Daniel Zavala-Araiza, Drew Nelson, Steven P. HamburgView Author Information Environmental Defense Fund, Austin, Texas 78701, United States*E-mail: [email protected]Cite this: Environ. Sci. Technol. 2015, 49, 13, 7524–7526Publication Date (Web):July 7, 2015Publication...
While natural gas produces lower carbon dioxide emissions than diesel during combustion, if enough methane is emitted across the fuel cycle, then switching a heavy-duty truck fleet from to can produce net climate damages (more radiative forcing) for decades. Using Technology Warming Potential methodology, we assess implications of switch in trucks. We consider spark ignition (SI) and high-pressure direct injection (HPDI) engines compressed liquefied gas. Given uncertainty surrounding several...
Urban concentrations of black carbon (BC) and other primary pollutants vary on small spatial scales (<100m). Mobile air pollution measurements can provide information fine-scale variation, thereby informing exposure assessment mitigation efforts. However, the temporal sparsity these presents a challenge for estimating representative long-term concentrations. We evaluate capabilities mobile monitoring in represention time-stable patterns by comparing against large set continuous fixed-site...
Abstract. Ambient air pollution poses a major global public health risk. Lower-cost quality sensors (LCSs) are increasingly being explored as tool to understand local problems and develop effective solutions. A barrier LCS adoption is potentially larger measurement uncertainty compared reference technology. The technical performance of various LCSs has been tested in laboratory field environments, growing body literature on uses primarily focuses proof-of-concept deployments. However, few...
The benefits of monitoring ambient air pollution with instruments mounted to ground-based, moving platforms include increased spatial resolution measurements and synchronous, fast-response close road sources for emissions analyses. However, these come at the cost obtaining a suitable number repeat visits each location in order achieve reliable representative estimates desired temporal resolution. Thus, methods that maximize information content derived from limited coverage mobile are needed...
We performed more than a year of mobile, 1 Hz measurements lung-deposited surface area (LDSA, the 20–400 nm diameter particles, deposited in alveolar regions lungs) and optically assessed fine particulate matter (PM2.5), black carbon (BC), nitrogen dioxide (NO2) central London. spatially correlated these pollutants to two urban emission sources: major roadways restaurants. show that optical PM2.5 is an ineffective indicator tailpipe emissions on roadways, where we do observe statistically...
Mobile air pollution measurements have the potential to provide a wide range of insights into emission sources and exposure. The analysis mobile data is, however, highly challenging. In this work we develop new regression-based framework for with aim improving draw inferences from such measurements. A quantile regression approach is adopted insight distribution NOx CO emissions in Central Outer London. We quantify intensity (ΔNOx/ΔCO2 ΔCO/ΔCO2) at different levels (τ) demonstrate how...
Abstract Estimates of methane emissions from natural gas production sites in the United States based on recent studies have been questioned due to possible malfunction Bacharach Hi Flow® Sampler (BHFS), primary measurement instrument used for two out five source types examined those (equipment leaks and chemical injection pumps). Without assessing whether BHFS occurred studies, we constrain underestimation associated with BHFS-based results by excluding potentially affected measurements....
While mobile, vehicle-based sampling of air quality has provided insights into pollutant distributions within cities, previous research been limited in using observed pollution hotspots to identify and localize unknown emission sources away from the road. Such "hyperlocal source identification" requires identified through mobile be linked by tracing atmospheric transport upwind hotspots. Here we analyze almost one year's worth observations two Google Street View cars driven around Salt Lake...
Recently enacted environmental justice policies in the United States at state and federal level emphasize addressing place-based inequities, including persistent disparities air pollution exposure associated health impacts. Advances quality measurement, models, analytic methods have demonstrated importance of finer-scale data analysis accurately quantifying extent inequity intraurban exposure, although necessary degree spatial resolution remains a complex context-dependent question.The...
Hazardous air pollutant (HAP) emission regulations in the US often rely on modeled estimates of ambient exposures. Model accuracy compared to real-world measurements HAPs is crucial for understanding and mitigating exposure associated health harms. While previous work shows are higher than regulatory model estimates, implications risk assessments rarely discussed. We provide a comprehensive comparison measured concentrations at 489 monitoring sites 79 HAPs. quantify how model-measurement...