By NOAA JUNE 1, 2020
The study team used measurements of atmospheric CO2 and its radiocarbon content (Δ14C) to ‘unmask’ the contribution of CO2 from fossil fuel combustion and cement production to the observed total. This map shows concentrations of CO2 across the US in the summer of 2010. Credit: Sourish Basu, CIRE
Tracking Fossil Fuel Emissions With Carbon-14
Researchers from NOAA and the University of Colorado have devised a breakthrough method for estimating national emissions of carbon dioxide from fossil fuels using ambient air samples and a well-known isotope of carbon that scientists have relied on for decades to date archaeological sites.
In a paper published in the journal the Proceedings of the National Academy of Sciences, they report the first-ever national scale estimate of fossil-fuel derived carbon dioxide (CO2) emissions obtained by observing CO2 and its naturally occurring radioisotope, carbon-14, from air samples collected by NOAA’s Global Greenhouse Gas Reference Network.
Carbon-14, or 14C, a very rare isotope of carbon created largely by cosmic rays, has a half-life of 5,700 years. The carbon in fossil fuels has been buried for millions of years and therefore is completely devoid of 14C. Careful laboratory analysis can identify the degree of 14C-depletion of the CO2 in discrete air samples, which reflects the contribution from fossil fuel combustion and cement manufacturing (which also has no 14C), otherwise known as the “fossil CO2” contribution. Knowing the location, date and time when the air samples were taken, the research team used a model of atmospheric transport to disentangle the CO2 variations due to fossil fuel combustion from other natural sources and sinks, and traced the man-made variations to the fossil CO2 sources at the surface.
The study team used measurements of atmospheric CO2 and its radiocarbon content (Δ14C) to ‘unmask’ the contribution of CO2 from fossil fuel combustion and cement production to the observed total. This map shows concentrations of CO2 across the US in the summer of 2010. Credit: Sourish Basu, CIRE
A new method for evaluating inventories
“This is a new, independent, and objective method for evaluating emission inventories that is based on what we actually observe in the atmosphere,” said lead author Sourish Basu, who was a CIRES scientist working at NOAA during the study. He is now a scientist at NASA’s Goddard Space Flight Center in Maryland.
While the link between fossil CO2 emissions and atmospheric 14C has been known for many decades, the construction of a national-scale emission estimate based on atmospheric 14C required the simultaneous development of precise measurement techniques and an emissions estimation framework, largely spearheaded over the past 15 years by NOAA scientist John Miller and University of Colorado scientist Scott Lehman.
“Carbon-14 allows us to pull back the veil and isolate CO2 emitted from fossil fuel combustion,” said Lehman, one of the paper’s authors. “It provides us with a tracer we can track to sources on the ground. “We can then add these up and compare to other emissions estimates at various time and space scales”
CIRES scientist Duane Kitzis approaches the air sampling station on Niwot Ridge, Colorado, part of NOAA’s Global Greenhouse Gas Reference Network, in this 2017 photo. The first air sample analyzed for carbon-14 as part of research into a new method of estimating fossil fuel emissions from ambient air was collected here in 2003. Credit: James Murnan, NOAA
Bottom-up vs. top-down
Accurately calculating emissions of carbon dioxide from burning fossil fuels has challenged scientists for years. The two primary methods in current use — “bottom up” inventories and “top down” atmospheric studies used in regional campaigns — each have their strengths and weaknesses.
“Bottom-up” estimates, such as those used in the EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks, are developed by counting CO2 emissions from various processes and fuel types, and then scaling up emissions based on records of fossil fuel use. In contrast, “top-down” estimates are based on measured changes in the concentrations of emitted gases in the atmosphere and wind patterns connecting the surface source regions with the measurement locations.
Bottom-up inventories can provide more detail than top-down methods but their accuracy depends on the ability to track all emission processes and their intensities at all times, which is an intrinsically difficult task with uncertainties that are not readily quantified. Top-down studies are limited by the density of atmospheric measurements and our knowledge of atmospheric circulation patterns but implicitly account for all possible sectors of the economy that emit CO2
The team constructed annual and monthly top-down fossil CO2 emission estimates for the U.S. for 2010, the first year with sufficient atmospheric samples to provide robust results. As one point of comparison, they compared their numbers to bottom-up estimates from a recent U.S. Environmental Protection Agency’s (EPA) report of 2010 emissions. The team’s estimate of the US annual total 2010 emissions was 5 percent higher than EPA’s central estimate. The new estimate is also significantly higher than those from other inventories commonly used in global and regional CO2 research. On the other hand, the atmospheric results appear to agree with a recent update of the Vulcan U.S. emissions data product developed by researchers at Northern Arizona University.
As these were the first estimates constructed using the new observing system, scientists cautioned that they should be considered provisional. Now they are busy applying the method to measurements from subsequent years, in order to determine if the differences they see are robust over time.
One of the benefits of this approach, according to the scientists, is that with an expanded 14C measurement network, there is the potential to calculate emissions from different regions — information that would augment EPA’s national totals. States such as California and collections of states such as the members of the eastern Regional Greenhouse Gases Initiative have created their own greenhouse gas mitigation targets, and the ability to independently evaluate regional emissions using top-down methods would help evaluate regional emissions reduction efforts.
“Independent verification of annual and regional totals and multi-year trends using independent methods like this would promote confidence in the accuracy of emissions reporting, and could help guide future emissions mitigation strategies,” said NOAA scientist John Miller.
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Reference:”Estimating US fossil fuel CO2 emissions from measurements of 14C in atmospheric CO2” by Sourish Basu, Scott J. Lehman, John B. Miller, Arlyn E. Andrews, Colm Sweeney, Kevin R. Gurney, Xiaomei Xu, John Southon and Pieter P. Tans, 1 June 2020, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.1919032117
The study was supported by NOAA, NASA, and the Department of Energy. Other members of the research team included scientists from Northern Arizona University and the University of California at Irvine.
What It’s Like To Breathe Some Of The Most Polluted Air In The World
Delhi is ranked as the world’s 6th most polluted city in terms of air quality, according to the World Health Organization. I wanted to know how pollution was affecting my health. So last week, I went to visit Dr. Sunil Kohli, the head physician of Hamdard Institute of Medical Sciences and Research, a public hospital in Delhi.
Kohli specializes in internal medicine. That’s the whole body. But a whopping 25 percent of his patients, he says, come in for respiratory problems.
My nostrils have a burning sensation almost all the time, I told the doctor. He nodded. The air pollution makes it hard for him to breathe sometimes, too.
Delhi’s air is a toxic concoction, according to a 2008 study by the Central Pollution Control Board, an Indian government body. It includes high levels of dangerous gases like carbon monoxide, nitrogen oxides, sulphur oxides, ozone gas, aerosols and particulate matter (PM) of varying sizes.The finer particles of pollutants — of 2.5 micrometers or smaller — are the most dangerous, the study reports, as they reach the deepest corners of our lungs and into our bloodstream, a 2018 WHO report points out.
Commuters in New Delhi wear face masks amid a layer of smog.Hindustan Times/Getty Images
This month, the concentration of these tiny pollutants was over 20 times the safe limit set by the World Health Organization.
The poor air quality in Delhi is largely due to transportation, industry and construction, according to a 2013 report by the Indian Journal of Community Medicine. In 2017, 10 million cars plied Delhi’s roads, estimates the Delhi government. The tailpipe exhaust and fumes from hot tires on asphalt pose a high risk to commuters’ health. On top of that, there’s dust from giant construction projects, exhaust from factories around the city, and crop fires hundreds of miles to the north.
So how does breathing in pollution affect health?
A 2016 study published in the Journal of Research and Medical Sciences found that long- and short-term exposure to air pollution has a direct association to respiratory and cardiovascular diseases, eye irritation, skin diseases and cancer, among other ailments.
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There’s also concerns that the body’s hormone system can be affected, according to a 2013 U.N. report — although there are no definitive findings on that yet.
People in Delhi are frustrated. There have been awareness campaigns and government committees to improve the air quality. There have even been restrictions on the use of fireworks on Diwali — one of the major Hindu festivals in India — which has been cited as a contributor to air pollution. Schools are closed on especially polluted days.
And after a public health emergency was declared due to high levels of pollution last November, city authorities implemented a scheme to reduce the number of cars on the road. Cars with even license plate numbers were allowed to drive on alternate days from cars with odd-numbered plates. The step was taken to temporarily cut down on vehicle emission and curb the pollution level.
But when I breathe in the air on my balcony, I still can’t tell a difference.
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To minimize the harmful effects of breathing, Delhi doctors suggest staying indoors whenever pollution levels spike. That means not being able to do some of the things that I enjoy — like dining outside or going on a picnic with friends.
Over the years, products like air purifiers, oxygen cans and filtered air masks have flooded the markets. Different types of masks are now available. Disposable ones cost as low as 15 cents, and reusable ones, which can last about six months, for $28. For the fashion-conscious, there are even “designer masks,” featuring colorful prints.
I recently bought my third reusable mask. It’s pretty sophisticated, or so I thought. It has head and neck straps, a nose bumper to seal the air and changeable air filters.
But when I showed my mask to Dr. Vineet Jain, a general physician at Jamia Hamdard Hospital, he wasn’t completely convinced of its effectiveness. Polluted air can still make its way through the mask, he says.
Jain suggested nasal filters, which you stick over your nostrils, helping you breathe through the tiny filters. He says they are slightly better in ensuring leak-proof filtering of the air. They look like bandages.
I just ordered them on Amazon.
Every day, I wonder how many years of my life I am giving up, breathing in New Delhi.
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How The ‘Lost Art’ Of Breathing Can Impact Sleep And Resilience May 27, 2020 TERRY GROSS LISTEN·36:2136-Minute ListenAdd toPLAYLIST Download Embed Transcript
Breathing slowly and deeply through the nose is associated with a relaxation response, says James Nestor, author of Breath.As the diaphragm lowers, you’re allowing more air into your lungs and your body switches to a more relaxed state.Sebastian Laulitzki/ Science Photo Library
Humans typically take about 25,000 breaths per day — often without a second thought. But the COVID-19 pandemic has put a new spotlight on respiratory illnesses and the breaths we so often take for granted.
Journalist James Nestor became interested in the respiratory system years ago after his doctor recommended he take a breathing class to help his recurring pneumonia and bronchitis.
While researching the science and culture of breathing for his new book, Breath: The New Science of a Lost Art, Nestor participated in a study in which his nose was completely plugged for 10 days, forcing him to breathe solely through his mouth. It was not a pleasant experience.
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“I went from snoring a couple minutes a night to, within three days, I was snoring four hours a night,” he says of the forced mouth-breathing. “I developed sleep apnea. My stress levels were off the charts. My nervous system was a mess. … I felt awful.”
Breath
The New Science of a Lost Art
by James Nestor
Hardcover, 280 pagespurchase
Nestor says the researchers he’s talked to recommend taking time to “consciously listen to yourself and [to] feel how breath is affecting you.” He notes taking “slow and low”breaths through the nose can help relieve stress and reduce blood pressure.
“This is the way your body wants to take in air,” Nestor says. “It lowers the burden of the heart if we breathe properly and if we really engage the diaphragm.”
Interview Highlights
On why nose breathing is better than mouth breathing
The nose filters, heats and treats raw air. Most of us know that. But so many of us don’t realize — at least I didn’t realize — how [inhaling through the nose] can trigger different hormones to flood into our bodies, how it can lower our blood pressure … how it monitors heart rate … even helps store memories. So it’s this incredible organ that … orchestrates innumerable functions in our body to keep us balanced.
On how the nose has erectile tissue
The nose is more closely connected to our genitals than any other organ. It is covered in that same tissue. So when one area gets stimulated, the nose will become stimulated as well. Some people have too close of a connection where they get stimulated in the southerly regions, they will start uncontrollably sneezing. And this condition is common enough that it was given a name called honeymoon rhinitis.
Enlarge this image
James Nestor’s previous book, Deep, focused on the science behind free diving.Julie Floersch/Riverhead Books
Another thing that is really fascinating is that erectile tissue will pulse on its own. So it will close one nostril and allow breath in through the other nostril, then that other nostril will close and allow breath in. Our bodies do this on their own. …
A lot of people who’ve studied this believe that this is the way that our bodies maintain balance, because when we breathe through our right nostril, circulation speeds up [and] the body gets hotter, cortisol levels increase, blood pressure increases. So breathing through the left will relax us more. So blood pressure will decrease, [it] lowers temperature, cools the body, reduces anxiety as well. So our bodies are naturally doing this. And when we breathe through our mouths, we’re denying our bodies the ability to do this.
On how breath affects anxiety
I talked to a neuropsychologist … and he explained to me that people with anxieties or other fear-based conditions typically will breathe way too much. So what happens when you breathe that much is you’re constantly putting yourself into a state of stress. So you’re stimulating that sympathetic side of the nervous system. And the way to change that is to breathe deeply. Because if you think about it, if you’re stressed out [and thinking] a tiger is going to come get you, [or] you’re going to get hit by a car, [you] breathe, breathe, breathe as much as you can. But by breathing slowly, that is associated with a relaxation response. So the diaphragm lowers, you’re allowing more air into your lungs and your body immediately switches to a relaxed state.
On why exhaling helps you relax
Because the exhale is a parasympathetic response. Right now, you can put your hand over your heart. If you take a very slow inhale in, you’re going to feel your heart speed up. As you exhale, you should be feeling your heart slow down. So exhaling relaxes the body. And something else happens when we take a very deep breath like this. The diaphragm lowers when we take a breath in, and that sucks a bunch of blood — a huge profusion of blood — into the thoracic cavity. As we exhale, that blood shoots back out through the body.
On the problem with taking shallow breaths
You can think about breathing as being in a boat, right? So you can take a bunch of very short, stilted strokes and you’re going to get to where you want to go. It’s going to take a while, but you’ll get there. Or you can take a few very fluid and long strokes and get there so much more efficiently. … You want to make it very easy for your body to get air, especially if this is an act that we’re doing 25,000 times a day. So, by just extending those inhales and exhales, by moving that diaphragm up and down a little more, you can have a profound effect on your blood pressure, on your mental state.
On how free divers expand their lung capacity to hold their breath for several minutes
The world record is 12 1/2 minutes. … Most divers will hold their breath for eight minutes, seven minutes, which is still incredible to me. When I first saw this, this was several years ago, I was sent out on a reporting assignment to write about a free-diving competition. You watch this person at the surface take a single breath there and completely disappear into the ocean, come back five or six minutes later. … We’ve been told that whatever we have, whatever we’re born with, is what we’re going to have for the rest of our lives, especially as far as the organs are concerned. But we can absolutely affect our lung capacity. So some of these divers have a lung capacity of 14 liters, which is about double the size for a [typical] adult male. They weren’t born this way. … They trained themselves to breathe in ways to profoundly affect their physical bodies.
Sam Briger and Joel Wolfram produced and edited this interview for broadcast. Bridget Bentz, Molly Seavy-Nesper and Deborah Franklin adapted it for the Web.
