Callahan is vice president of federal programs at Earth Networks, an environmental monitoring company based in Germantown that recently agreed — with the help of the National Institute of Standards and Technology — to expand the number of greenhouse gas sensors around the world. How does Earth Networks measure greenhouse gases?
The traditional way of quantifying greenhouse gas emissions is from a bottoms-up approach, where you take inventories of all the industrial sources of the gases and make assumptions about how much is being emitted into the atmosphere. What we’re doing — we’re actually installing these tall towers with sensors at the top that measure the concentrations of emissions in the atmosphere. You need to measure both — the sources of the emissions and the concentration that is actually in the air — in order to determine what kind of effect they are having on the environment.
