A team of scientists at the National Institute of Standards and Technology has developed an instrument that could be used to determine the percentage of carbon found in the atmosphere, that comes from the burning of fossil fuels.
The core concept of the technology is similar to the one used in carbon dating, which essentially measures relative amounts of carbon isotopes in order to determine the age of an object. As useful as carbon dating may be, its use has been extremely limited by its high costs. This is due to the fact that the carbon-14 isotope (which forms in the upper atmosphere) decays at a fast rate, having a half-life of 7,730 years.
This is not a problem when having to determine the age of an archaeological artifact or a piece of a well-preserved bone, as the carbon-14 contained in a human being only starts to decay after its death. However, extremely accurate instruments are required in order to measure the age of carbon-14 that comes from the plants and beings that have since turned into fossil fuel. The carbon isotopes found in these remains have decayed thousands of years ago, and are extremely difficult to analyze.
Fortunately, the new instrument is not only small enough to be placed on a laboratory benchtop, but also cheap to operate and it is extremely accurate. It can be used to analyze gases by detecting the wavelengths of light that they absorb, in order calculate the carbon isotopes found in them. The isotopes can then be used to determine if the gases come from fossil fuels or not.
The scientists achieved the great sensitivity required in order to perform these measurements by taking the cavity ringdown spectroscopy technology that was already in use and further developing it. They build a system that cools the instrument and allows it to sense faint signals of light absorption.
However, there are several other uses for the device. Fuels and bioplastics can also be burned, in order to analyze the resulting CO2 gas, thus giving us the ability to determine what fraction of a fuel mixture or a material is biofuel.
It is important to keep in mind that even with this technology, a large number of samples must be collected in order to calculate fossil fuel emissions in a certain geographic area. After the samples are collected, they must simply be analyzed. Cities, industrial zones, or other heavily polluted areas will have smaller than normal quantities of heavy CO2.