Memorial Hall CO₂ FAQ

1. Why are you measuring CO₂ levels outside Memorial Hall?
2. How are you measuring CO₂ levels outside Memorial Hall?
3. How can I download historical data?
4. Why isn’t the CO₂ timestamp current?
5. How did you get this idea to measure CO₂ levels?
6. When was the last time you calibrated the analyzer?
7. What can I do to reduce my carbon footprint?
8. Where can I get more information?

1. Why are you measuring CO₂ levels outside Memorial Hall?

Humans are ingenious–especially when it comes to how we power our lives.  For example, we figured out how to sail across the great oceans of the world.  Wind power is really just solar power.  Very recent sunshine.  But we’ve also figured out how to power our lives with much older sunshine: fossil fuels.

In Harrisonburg, Virginia, for example, much of our baseload electrical consumption is powered by Appalachian coal, which is essentially 300-million-year-old sunshine.  My department’s vans run on gasoline, which is largely 50-million-year-old sunshine (aka crude oil), mostly from Canada.  Yes, three vans now run on propane thanks to generous conversions funded by Virginia Clean Cities, but that propane is still the result of really really old sunshine hitting this planet. These are great examples of fossil fuel.  A typical lawnmower uses the fossil fuel gasoline; solar-powered lawnmowers, by contrast, looks like this …

From paulstforest_100607

All told, in the United States, we consume about 100 quadrillion british thermal units (BTUs) of energy every year, which is the same as 1·10^17 BTUs or, as my students will be more familiar with, 1E17 BTUs.  1 BTU is the energy it takes to raise the temperature of 1 pound of water by 1 degree F.  Since there are about pi (3.1415…) E7 seconds in a year, we Americans consume about 3E9 BTUs every second.  If there are 300 million Americans (we like to round, with permission from, among other sources, Guesstimation), that’s 3E8 Americans, so 3E9 BTUs every second/3E8 Americans means each of us, on average, uses 10 BTUs every second of every minute of every hour of every day of every year…. (We love unit conversions.)

But there are consequences to how we get those 10 BTUs every second. For example,

This fossil fuel consumption results in the production of carbon dioxide from what I teach my students starts out as sugar, or carbohydrate.  So as our planetary appetite for fossil fuels increases, so too do our emissions of CO₂.

We have very precise and accurate measurements of CO₂ since the 1950s, and now, the Department of Geology & Environmental Science, in a collaboration with the Center for Instructional Technology, has launched a real-time (not corrected for daylight savings!) display of CO₂ levels outside Memorial Hall in Harrisonburg, Virginia.

2. How are you measuring CO₂ levels outside Memorial Hall?

The department purchased a Licor 820 infrared gas analyzer.

With some plumbing that included a work order to have a hole drilled through the aluminum frame in the Soil Lab’s only window (shown here)

, a low-cost 6V DC pump, a flow regulator to ensure air is not pumped at rates greater than a half-liter per minute, and a peak-broadening/water-trap mason jar, we pump outside air into the gas analyzer.  The gas analyzer produces a XML datafeed that Andreas Knab, JMU Center for Instructional Technology, intercepts with some clever code.  Data are reported out as real-time CO₂ concentrations outside Memorial Hall, and simultaneously archived for research and teaching purposes.

3. How can I download historical data?

Go here to download data.

4. It’s 10:42 am.  Why doesn’t the CO₂ badge have a timestamp from 1 minute ago, and instead is showing the CO₂ concentration from 3:17 am (or a couple days ago!)? Why is there a 1-, 2-, or 5-hour gap in the data?

Our system is set up to multitask. Occasionally during Fall semester, we use the Licor 820 to measure how much CO₂ microbes produce as part of a GEOL340 (Environmental soil science) laboratory procedure (and undergraduate-fueled research), and these headspace samples we inject briefly interrupt data collection and reporting.  Here’s an image showing how we replumb the 820′s gas stream so that it gets nitrogen gas as a carrier gas for the headspace gas sample:

In Fall 2011, this system received an uninterruptible power supply (UPS) so power-failure-associated data gaps are now minimized.

The badge always shows the last best CO₂ concentration.

5. How did you get this idea to measure CO₂ levels?

In 1958, Dave Keeling started recording CO₂ levels atop Mauna Loa.

He noticed an interesting diurnal (24-hour) pattern with his CO₂ data, one that is evident in our data (click on the annual graph to see a week’s worth of data). You should see something like this:

This is from this Keeling Curve website: In the 1950s, Keeling repeated these measurements in the rain forests of Olympic peninsula and high mountain forests in Arizona. Everywhere the data were the same …strong diurnal behaviour with steady values of about 310 ppm in the afternoon. The explanation for the results came from a book on meteorology describing diurnal patterns in turbulence in the atmosphere. In the afternoon Dave Keeling was measuring CO2 concentrations representative of the “free atmosphere”, concentrations that prevailed over a large part of the Northern Hemisphere. At night time with a lower boundary layer the CO2 concentration was heavily influenced by respiration from local plants and soils.

In the decades since, Keeling’s data have helped highlight how humans are changing the composition of the planet’s atmosphere, principally through increasing emissions of greenhouse gases such as CO₂.  Here is more background on what has become known as the Keeling curve.  I was also aware of websites such as co2now.org, but this lacked hourly dynamism or any sense of what the numbers are in my neighborhood.

So I wanted a more local, and less global, measure of real-time CO₂ that I could use for teaching and research.

Licor technical support folks pointed us to Dr. Matsumoto’s efforts to track real-time CO₂ levels outside (above) the University of Minnesota.  Here is a screenshot of one of his months of CO₂ data:

And if you were to click on that one-month snapshot of data, you’d see the latest week of data:

Dr. Matsumoto was helpful in providing design guidance, and brought up the same atmospheric boundary layer issue that Dave Keeling noticed in the 1950s.

6. When was the last time you calibrated the analyzer?

We last calibrated the Licor 820 in late Fall 2011.

7. What can I do to reduce my carbon footprint?

Two things.

First, be mindful.  Be mindful of what age sunshine you’re fueling your life with.

• Your vehicles: do they run on gasoline, ethanol/gasoline, petrodiesel, biodiesel, solar-power (plug-in hybrid/electric), or coal-power (plug-in hybrid/electric);
• Your body: do you fuel yourself with local or foreign food, organic amendments or chemical/fossil-fuel-derived fertilizers, grass-fed or grain-fed, lentils or lamb? and
• Your home/workplace: are you on-the-grid or off-the-grid; do you use incandescent or compact fluorescent or light-emitting diode lightbulbs; do you heat via oil, natural gas, electricity, or wood; and is your home/workplace more or less weatherized than the typical home/workplace?

Second, talk to your family, your friends, and your neighbors about the carbon cycle.

8. Where can I get more information about this Memorial Hall CO₂ Project?

Feel free to visit or contact the Soils Lab; call (540) 568-6130 for more information.  We would be happy to collaborate on expanding our portfolio of teaching exercises built around these types of data. Any and all feedback are most welcome.