Measuring greenhouse gases on the go

mobile emissions lab
UCR’s mobile emissions lab on location at a dairy manure lagoon in Southern California.








By Sarah Nightingale, UC Riverside

To pinpoint sources of air pollution across California, two UC Riverside professors are taking to the road.

They’ll be traveling in the university’s new Mobile Isotope Laboratory, a Mercedes Benz transport van fitted with a suite of instruments that can measure the flux of greenhouse gases in the environment in real time. The scientists leading the project are Francesca Hopkins, an assistant professor of climate science and sustainability in the Department of Environmental Sciences, and Marilyn Fogel, the Wilbur H. Mayhew Endowed Professor of Geo-Ecology in the Department of Earth Sciences.

Fogel’s endowed chair is named for a UC Riverside professor who worked tirelessly for decades to add lands to the UC Natural Reserve System. 

By pumping the surrounding air into the laser-based sensor system, the researchers can measure the amount of methane, ethane, carbon dioxide, water vapor, and nitrous oxide in the atmosphere. They can also identify the naturally occurring stable isotopes of individual elements — carbon, nitrogen, and oxygen — in the gases. The isotope mix reveals where the emissions came from and whether they originated through human activities or natural processes.

mobile emissions lab
Sensors in the mobile emissions lab measure atmospheric methane, methane isotopes, carbon dioxide, ethane, and water vapor.

The van is equipped with a diesel generator and an inverter, which power the laser-based machines and air conditioning needed to work in remote locations such as UC Natural Reserve System sites.

“By analyzing air samples in real time while the vehicle is in motion, we can identify pollution hotspots and further study them to learn the sources and concentrations of the emissions,” said Fogel, director of UCR’s Environmental Dynamics and GeoEcology (EDGE) Institute. “The instruments in the mobile lab will enable us to take a comprehensive look at current greenhouse gas emissions across California, which will provide a baseline that the state can use as it works to reduce air pollution caused by transportation, agriculture, and industry.”

Valerie Carranza, a graduate student in Hopkins’ research group, said the mobile laboratory makes data collection much easier. “Before we had access to the mobile lab, it was challenging to make these kinds of measurements in the field because the laser instruments require power and cooling,” Carranza said. “The mobile lab has vastly increased the number of locations we can visit and the amount of measurements we can make.”

Since the mobile lab’s rollout earlier this month, researchers have conducted emissions testing at dairies in Southern California. They plan to use it at the NRS’s Boyd Deep Canyon Desert Research Center as well as the Salton Sea this fall.

Francesca Hopkins, principal investigator of a Lab Fees grant from the University of California Office of the President, and her group have been testing the mobile van this summer and have an ambitious schedule for fall. Darrel Jenerette, professor of landscape ecology, and Peter Homyak, assistant professor of environmental sciences, hope to use the mobile lab to work on their National Science Foundation-funded project on “hot” agriculture in the Imperial Valley, where temperatures can reach 110 degrees Fahrenheit.

Lab exploits are available on Instagram @ucrlimeavocado, which stands for UCR “Laboratory for Isotope Measurements in the Environment” (LIME)/Analysis for On-road Capture of Atmospheric Data and Observations (AVOCADO).

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