The oxygen and carbon in our atmosphere play a crucial role in the climate system, helping to make water, food, and life possible.
They are also the most abundant and crucial elements in our planet, contributing an estimated 40 per cent of the total.
And they can be measured.
But how do you know what oxygen is?
It’s easy to just take a breath and count.
You don’t know how many molecules are there in air.
Theoretical physicist Brian Cox, who is a research associate at the University of Leeds in the UK, thinks we might be able to do better.
“We have been thinking about how we can improve our measurement capabilities, and so we have developed an experimental technique for measuring the composition of air,” he says.
He says it’s a process called “quantum absorption spectroscopy”.
“It involves a detector on a spectrometer that can detect molecules in air by measuring how many photons (electrons) they produce,” Cox says.
This means a sensor that picks up and records the wavelengths of light emitted by the atoms.
“This is a bit like taking a sample of air, but it’s actually measuring how much oxygen is in it.”
This information is then used to calculate the ratio of oxygen to carbon in the air.
In the laboratory, Cox has been using this technique to make measurements of carbon and oxygen in a mixture of air and water.
So far, he says, the method works pretty well.
“The oxygen is around the right level, the carbon is around right level.
There’s a little bit of overlap,” he explains.
But he cautions that the technique isn’t perfect.
“It does give us an indication of what is going on with the carbon in water, but we need to be careful that the ratio is not a little off,” he adds.
So, how do we measure the oxygen in our breath?
To get an idea, Cox is working on a new system, called a gas chromatograph, that can measure the gas’s oxygen and the amount of carbon it contains.
The idea is that it can pick up the wavelengths in the atmosphere to make an estimate of how much the oxygen is present.
Cox says that this method is still a bit of a work in progress.
“But it looks like we can do a reasonably good approximation of the amount that the oxygen actually is in the breath,” he told New Scientist.
“So it looks promising.”
He says the technique is being developed to improve on the method that’s been used for years to measure carbon dioxide.
“At this point we’re in a position where we’re actually starting to get better at this.
And I think that’s good, because we’re trying to improve it,” he said.
The oxygen level in air is measured by a spectrograph.
The gas chromatography system, also known as GC-MS, uses a spectrophotometer to measure the wavelengths emitted by atoms of oxygen and other gases.
The spectrometers are mounted on a high-pressure gas cylinder and have an external sensor that can pick out the molecules that are emitting light.
The detector is a tiny, white box with an attached probe.
In theory, this sensor is a pretty cheap way of measuring the gas, so Cox thinks it will be very useful in the future.
“In the next 20 years, I think you’ll probably be able, with these spectromers, to do a lot more than just measure the air,” Cox said.
“You’ll be able actually measure oxygen, carbon, nitrogen, and the oxygen and nitrogen in water and food.”
The technique is called “electronic time tables” (ETTs).
“This [technique] gives us an idea of the composition in the whole system, and we can use this information to build models of the environment,” Cox explains.
He estimates that the technology will allow us to do things like determine if we are in an ocean, or if we have a large, warm climate, and how much carbon is in our soil.
In some ways, Cox hopes this technique can also be used to measure how much energy we produce.
“There are many ways to measure this, but they all have some limitations,” he notes.
“One of the limitations of electronic time tables is that you have to be able measure the time when the molecules in the system are emitted, and it’s not very easy to do.”
But the technology could help us to get more accurate information about the climate and climate change.
“If we can get this information, we could be able improve our climate models to better predict changes in our climate,” Cox added.
He also hopes to see the technology used to predict changes to air quality.
“I think it’s important to be doing that,” he added.
The technique could also be applied to the measurements of methane and other greenhouse gases.
“Methane is a greenhouse gas, and if