Development of Atmospheric Tracer Methods To Measure Methane Emissions from Natural Gas Facilities and Urban Areas

A new, integrated methodology to locate and measure methane emissions from natural gas systems has been developed. Atmospheric methane sources are identified by elevated ambient CH4 concentrations measured with a mobile laser-based methane analyzer. The total methane emission rate from a source is obtained by simulating the source with a sulfur hexafluoride (SF6) tracer gas release and by measuring methane and tracer concentrations along downwind sampling paths using mobile, real-time analyzers. Combustion sources of methane are distinguished from noncombustion sources by concurrent ambient carbon dioxide measurements. Three variations on the tracer ratio method are described for application to (1) small underground vaults, (2) aboveground natural gas facilities, and (3) diffuse methane emissions from an entire town. Results from controlled releases and from replicate tests demonstrate that the tracer ratio approach can yield total emission rates to within approximately ±15%. The estimated accuracy of emission estimates for urban areas with a variety of diffuse emissions is ±50%. © 1995, American Chemical Society. All rights reserved

Earth Exploration Toolbook Chapter: Exploring Regional Differences in Climate Change

In this activity, users download and graph modeled climate data to explore variability in climate change. Most people know that climate changes are predicted over the next hundred years, but they may not be aware that these changes are likely to vary from region to region. Using data from the University of New Hampshire's Earth Science Information Partner, a digital library of Earth Science data, users will obtain annual predictions for minimum temperature, maximum temperature, precipitation, and solar radiation for each of these 5 states: New York, Georgia, Colorado, Minnesota, and California. Data will span the years 2000 through 2100. Users will import the data into Excel and analyze it to see what, if any, regional variability exists. Finally, they will download data for their own state, compare these results to the results from the other five states and use their results to answer a series of questions related to climate change. Educational levels: Graduate or professional, High school, Undergraduate lower division, Undergraduate upper division