from devastating forest fires For polar bears clinging to melting floating ice, there is no shortage of shocking images to illustrate the need for action on climate change. But collecting reliable data to track the rate of change — and help determine how to address it — is no easy feat.
Scientists at the National Physical Laboratory in Teddington, southwest London, are using precision monitoring equipment to measure pollutants and track our impact on the planet more accurately than ever before.
The lab’s newest instrument is the Boreas, a laser spectrometer designed to collect and analyze methane — a greenhouse gas emitted by dozens of human activities, from agriculture to fuel burning. In a modest communications tower in Heathfield, Surrey, Boreas operates 24 hours a day in all weather conditions to sample large amounts of air. The machine uses a length of tubes filled with microplastics, which are then cooled to -160 degrees Celsius, allowing researchers to return to NPL headquarters to cryogenically separate methane molecules from oxygen and nitrogen, which freeze at very low temperatures.
The goal is to determine the relative concentration of different methane particles and gain a better understanding of the source of the pollutants, explains Emal Safi, senior research scientist at NPL. “While previous devices were able to measure methane concentrations, these data alone don’t tell us much about where the methane is coming from,” she says.
Methane is a molecule consisting of one carbon atom surrounded by four hydrogen atoms (its chemical formula is CH4). However, there are different types of methane in the air, called methane isotopes. “Different processes produce methane with very small differences in the relative amount of each isotope, so the relative proportion of each can be used as a signature to identify its source,” Safi says.
So far, the readings show the researchers what they expected: “We’re seeing methane that has the signature of the Northern Hemisphere background – relatively fresh air from the Atlantic – and some local agricultural sources,” says Chris Renick, who is also the senior research scientist on the Boreas team. “It depends on the direction of the wind on any given day.”
What makes Boreas unique is its potential: In the future, NPL hopes to build more devices like it and deploy it to various regions, including the Arctic, where large amounts of methane can be trapped in permafrost. “We use data from our Heathfield lab to contribute to estimates of UK methane emissions,” explains Rennick. “However, there are many other networks in many other countries that may also benefit from measurements that Boreas can make – this would allow the instrument to help reduce global methane emissions.”
Boreas is one of dozens of unique equipment that measures contaminants in the NPL. Historically one of the most important is the Kibble Balance, a set of high-precision scales developed in the 1970s to compare electrical and mechanical energy. Fifty years later, the device is used to weigh individual air molecules to determine methane concentrations.
The main role of researchers such as those at Boreas is not to conduct climate research, or even to provide evidence for climate change itself. They are metrology experts by trade – there to study and monitor metrology to keep the science as accurate as possible.
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