Mobile Measurements of Climate Forcing Agents: Application to Methane Emissions from Landfill and Natural Gas Compression
Creators: name: Jakober, Chris A.
name: Mara, Steve L.
name: Ying-Kuang Hsu
name: Herner, Jorn D.
Publisher: name: Taylor & Francis
Year: 2015
Subjects: subject: Plant Biology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: Biological Sciences
subject: Sociology
subject: FOS: Sociology
subject: FOS: Sociology
subject: Ecology
subject: Chemistry
subject: Earth and Environmental Sciences

description: ABSTRACTMeasuring greenhouse gas (GHG) source emissions provides data for validation of GHG inventories, which provide the foundation for climate change mitigation. Two Toyota RAV4 electric vehicles were outfitted with high precision instrumentation to determine spatial and temporal resolution of GHGs (e.g., nitrous oxide, methane (CH<sub>4</sub>), and carbon dioxide (CO<sub>2</sub>)), and other gaseous species and particulate metrics found near emission sources. Mobile measurement platform (MMP) analytical performance was determined over relevant measurement time scales. Pollutant residence times through the sampling configuration were measured, ranging from 3 to 11 seconds, enabling proper time alignment for spatial measurement of each respective analyte. Linear response range for GHG analytes was assessed across expected mixing ratio ranges, showing minimal regression and standard error differences between 5, 10, 30 and 60 second sampling intervals and negligible differences between the two MMPs. GHG instrument drift shows deviation of less than 0.8% over a 24-hour measurement period.These MMPs were utilized in tracer-dilution experiments at a California landfill and natural gas compressor station (NGCS) to quantify CH<sub>4</sub> emissions. Replicate landfill measurements during October of 2009 yielded annual CH<sub>4</sub> emissions estimates of 0.10 ± 0.01, 0.11 ± 0.01 and 0.12 ± 0.02 million tonnes of CO<sub>2</sub> equivalent (MTCO<sub>2</sub>E). These values compare favorably to California GHG Emissions Inventory for 2007, 2008, and 2009 of 0.123 and 0.125, and 0.126 MTCO<sub>2</sub>E/year respectively for this facility. Measurements to quantify NGCS boosting facility-wide emissions, during June 2010 yielded an equivalent of 5400 ± 100 TCO<sub>2</sub>E/year under steady state operation. However, measurements during condensate transfer without operational vapor recovery yield an instantaneous emission rate of 2-4 times greater, but was estimated to only add 12 TCO<sub>2</sub>E/year overall. This work displays the utility for mobile GHG measurements to validate existing measurement and modeling approaches, so emission inventory values can be confirmed and associated uncertainties reduced. IMPLICATIONSMeasuring greenhouse gas (GHG) source emissions provides data and validation for GHG inventories, the foundation for climate change mitigation. Mobile measurement platforms with robust analytical instrumentation completed tracer-dilution experiments in California at a landfill and natural gas compressor station (NGCS) to quantify CH<sub>4</sub> emissions. Data collected for landfill CH<sub>4</sub> agree with the current California emissions inventory, while NGCS data show the possible variability from this type of facility. This work displays the utility of mobile GHG measurements to validate existing measurement and modeling approaches, such that emission inventory values can be confirmed, associated uncertainties reduced, and mitigation efforts quantified.