Taking the Earth’s Temperature

By By Trish Barker

October 7, 2005

It’s been found in salmon, polar bears and dolphins. It’s been found in the Great Lakes, the Arctic and the Mediterranean. It’s been found in apples, green beans, bread and ground beef. It’s been found in the bloodstreams of people worldwide.

It’s perfluorooctanoic acid (PFOA), a persistent, bioaccumulative compound that has come under scrutiny from the Environmental Protection Agency because of its as yet unknown potential for toxicity in human beings. The EPA issued a preliminary risk assessment regarding PFOA in 2003, but there are still more questions than answers about the chemical’s effects on human beings and how it has come to be so pervasive in the global environment.

In an attempt to answer some of those questions, University of Illinois atmospheric scientist Donald Wuebbles uses computing resources at NCSA to investigate the chain of events that leads to the presence of potentially toxic PFOA in the environment.

“Here’s this substance that’s found in nature,” Wuebbles said. “So the science question arises, “Where is this stuff coming from?”

Since the early 1950s, PFOA (C8HF15O2) has been used in the manufacture of fluoropolymers, fluorine-containing plastics that are components of non-stick cookware (such as DuPont’s Teflon), water-repellant fabrics, and other industrial products. Scientists have also theorized that PFOA can be formed as a result of the breakdown of fluorotelomer alcohols (FTOHs), chemicals that are widely used in fabrics and carpets (to provide stain resistance), in fast-food packaging (to help paper wrappers and cardboard boxes stand up to grease), and in some paints (to enhance dispersal). Millions of kilograms of fluorotelomer alcohols are produced around the world each year.

In recent years, PFOA has been observed in flora, fauna and human beings around the world, leading to concerns about potential health risks. Studies in rats and rabbits have demonstrated some adverse affects from PFOA exposure, ranging from reduced birth weights in offspring to enlarged kidneys and livers and even death. The results of studies of workers who have been exposed to PFOA are mixed, however, with no clear-cut picture of the chemical’s danger or safety yet emerging. What is clear is that PFOA and its chemical kin are not metabolized in the body and that they are bioaccumulative, meaning they hunker down in human and animal tissue and their levels continue to mount year after year.

Wuebbles set out to test the hypothesis that the PFOA observed in the environment is a by-product of the breakdown of these fluorotelomer alcohols and to explain why it is so widely observed. He decided to focus on 8:2 FTOH (C8F17CH2CH2OH) because of its importance in the $500 million annual fluorotelomer alcohol market.

The atmospheric oxidation mechanism for 8:2 FTOH, constructed from data in prior publications, was integrated into two atmospheric chemistry models: a two- dimensional model from the University of Illinois and the three-dimensional IMPACT model developed at Lawrence Livermore National Laboratories and the University of Michigan. These models calculate the chemistry of the breakdown of the initial compound and the physics that control how the resulting products are carried through the atmosphere.

Using estimates of the amount of 8:2 FTOH present in the atmosphere and factoring in locations where the chemical was being generated, Wuebbles ran calculations using both models on Copper, NCSA’s IBM p690 high-performance computing system. These simulations mapped the concentration and global dispersal of PFOA over time.

The simulation results showed molar yields of PFOA in the range of 1-to-10 percent, depending on the location and season. This yield corresponds well with what has actually been observed in nature. The distribution of PFOA shown by the simulations also correlated closely with environmental observations. In the simulation results, PFOA was ubiquitous in the Northern Hemisphere, as it is in reality.

Also correlating closely with real-world observations, the simulated concentration of PFOA was higher at locations far from its source, with the highest PFOA levels over the Atlantic and Pacific oceans, North Africa, and the Arctic during the summer. This somewhat counterintuitive result is explained by the fact that the reaction that forms PFOA competes with another reaction involving nitrogen oxides; larger concentrations of nitrogen oxides favor the competing reaction and result in less PFOA being formed. The sources of fluorotelomer alcohol emissions are also typically associated with high concentrations of nitrogen oxides, so less PFOA is formed close to the source of its parent compound, and more PFOA is formed farther away.

Wuebbles also noted how concentrations of PFOA in the simulation fluctuated throughout the year. In the Arctic, the PFOA concentration is high during the summer, falling by an order of magnitude during the winter. In fact, the simulation showed lower levels of PFOA during the winter throughout the Northern Hemisphere. This is due to the fact that photochemical activity slows during the winter months, creating a lull in the production of PFOA in the atmosphere.

Because the results of the simulation accorded so well with what has been observed in the environment, Wuebbles believes the study presents persuasive evidence that 8:2 FTOH degrades in the atmosphere to form PFOA and other perfluorocarboxylic acids and that these chemicals are then dispersed around the world.

Wuebbles said he would like to carry out finer-grained simulations to tease out in more detail the reactions and transport mechanisms that lead to the globally ubiquitous PFOA pollution. 

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industry updates delivered to you every week!

Q&A with Nvidia’s Chief of DGX Systems on the DGX-GB200 Rack-scale System

March 27, 2024

Pictures of Nvidia's new flagship mega-server, the DGX GB200, on the GTC show floor got favorable reactions on social media for the sheer amount of computing power it brings to artificial intelligence.  Nvidia's DGX Read more…

Call for Participation in Workshop on Potential NSF CISE Quantum Initiative

March 26, 2024

Editor’s Note: Next month there will be a workshop to discuss what a quantum initiative led by NSF’s Computer, Information Science and Engineering (CISE) directorate could entail. The details are posted below in a Ca Read more…

Waseda U. Researchers Reports New Quantum Algorithm for Speeding Optimization

March 25, 2024

Optimization problems cover a wide range of applications and are often cited as good candidates for quantum computing. However, the execution time for constrained combinatorial optimization applications on quantum device Read more…

NVLink: Faster Interconnects and Switches to Help Relieve Data Bottlenecks

March 25, 2024

Nvidia’s new Blackwell architecture may have stolen the show this week at the GPU Technology Conference in San Jose, California. But an emerging bottleneck at the network layer threatens to make bigger and brawnier pro Read more…

Who is David Blackwell?

March 22, 2024

During GTC24, co-founder and president of NVIDIA Jensen Huang unveiled the Blackwell GPU. This GPU itself is heavily optimized for AI work, boasting 192GB of HBM3E memory as well as the the ability to train 1 trillion pa Read more…

Nvidia Appoints Andy Grant as EMEA Director of Supercomputing, Higher Education, and AI

March 22, 2024

Nvidia recently appointed Andy Grant as Director, Supercomputing, Higher Education, and AI for Europe, the Middle East, and Africa (EMEA). With over 25 years of high-performance computing (HPC) experience, Grant brings a Read more…

Q&A with Nvidia’s Chief of DGX Systems on the DGX-GB200 Rack-scale System

March 27, 2024

Pictures of Nvidia's new flagship mega-server, the DGX GB200, on the GTC show floor got favorable reactions on social media for the sheer amount of computing po Read more…

NVLink: Faster Interconnects and Switches to Help Relieve Data Bottlenecks

March 25, 2024

Nvidia’s new Blackwell architecture may have stolen the show this week at the GPU Technology Conference in San Jose, California. But an emerging bottleneck at Read more…

Who is David Blackwell?

March 22, 2024

During GTC24, co-founder and president of NVIDIA Jensen Huang unveiled the Blackwell GPU. This GPU itself is heavily optimized for AI work, boasting 192GB of HB Read more…

Nvidia Looks to Accelerate GenAI Adoption with NIM

March 19, 2024

Today at the GPU Technology Conference, Nvidia launched a new offering aimed at helping customers quickly deploy their generative AI applications in a secure, s Read more…

The Generative AI Future Is Now, Nvidia’s Huang Says

March 19, 2024

We are in the early days of a transformative shift in how business gets done thanks to the advent of generative AI, according to Nvidia CEO and cofounder Jensen Read more…

Nvidia’s New Blackwell GPU Can Train AI Models with Trillions of Parameters

March 18, 2024

Nvidia's latest and fastest GPU, codenamed Blackwell, is here and will underpin the company's AI plans this year. The chip offers performance improvements from Read more…

Nvidia Showcases Quantum Cloud, Expanding Quantum Portfolio at GTC24

March 18, 2024

Nvidia’s barrage of quantum news at GTC24 this week includes new products, signature collaborations, and a new Nvidia Quantum Cloud for quantum developers. Wh Read more…

Houston We Have a Solution: Addressing the HPC and Tech Talent Gap

March 15, 2024

Generations of Houstonian teachers, counselors, and parents have either worked in the aerospace industry or know people who do - the prospect of entering the fi Read more…

Alibaba Shuts Down its Quantum Computing Effort

November 30, 2023

In case you missed it, China’s e-commerce giant Alibaba has shut down its quantum computing research effort. It’s not entirely clear what drove the change. Read more…

Nvidia H100: Are 550,000 GPUs Enough for This Year?

August 17, 2023

The GPU Squeeze continues to place a premium on Nvidia H100 GPUs. In a recent Financial Times article, Nvidia reports that it expects to ship 550,000 of its lat Read more…

Shutterstock 1285747942

AMD’s Horsepower-packed MI300X GPU Beats Nvidia’s Upcoming H200

December 7, 2023

AMD and Nvidia are locked in an AI performance battle – much like the gaming GPU performance clash the companies have waged for decades. AMD has claimed it Read more…

DoD Takes a Long View of Quantum Computing

December 19, 2023

Given the large sums tied to expensive weapon systems – think $100-million-plus per F-35 fighter – it’s easy to forget the U.S. Department of Defense is a Read more…

Synopsys Eats Ansys: Does HPC Get Indigestion?

February 8, 2024

Recently, it was announced that Synopsys is buying HPC tool developer Ansys. Started in Pittsburgh, Pa., in 1970 as Swanson Analysis Systems, Inc. (SASI) by John Swanson (and eventually renamed), Ansys serves the CAE (Computer Aided Engineering)/multiphysics engineering simulation market. Read more…

Choosing the Right GPU for LLM Inference and Training

December 11, 2023

Accelerating the training and inference processes of deep learning models is crucial for unleashing their true potential and NVIDIA GPUs have emerged as a game- Read more…

Intel’s Server and PC Chip Development Will Blur After 2025

January 15, 2024

Intel's dealing with much more than chip rivals breathing down its neck; it is simultaneously integrating a bevy of new technologies such as chiplets, artificia Read more…

Baidu Exits Quantum, Closely Following Alibaba’s Earlier Move

January 5, 2024

Reuters reported this week that Baidu, China’s giant e-commerce and services provider, is exiting the quantum computing development arena. Reuters reported � Read more…

Leading Solution Providers

Contributors

Comparing NVIDIA A100 and NVIDIA L40S: Which GPU is Ideal for AI and Graphics-Intensive Workloads?

October 30, 2023

With long lead times for the NVIDIA H100 and A100 GPUs, many organizations are looking at the new NVIDIA L40S GPU, which it’s a new GPU optimized for AI and g Read more…

Shutterstock 1179408610

Google Addresses the Mysteries of Its Hypercomputer 

December 28, 2023

When Google launched its Hypercomputer earlier this month (December 2023), the first reaction was, "Say what?" It turns out that the Hypercomputer is Google's t Read more…

AMD MI3000A

How AMD May Get Across the CUDA Moat

October 5, 2023

When discussing GenAI, the term "GPU" almost always enters the conversation and the topic often moves toward performance and access. Interestingly, the word "GPU" is assumed to mean "Nvidia" products. (As an aside, the popular Nvidia hardware used in GenAI are not technically... Read more…

Shutterstock 1606064203

Meta’s Zuckerberg Puts Its AI Future in the Hands of 600,000 GPUs

January 25, 2024

In under two minutes, Meta's CEO, Mark Zuckerberg, laid out the company's AI plans, which included a plan to build an artificial intelligence system with the eq Read more…

Google Introduces ‘Hypercomputer’ to Its AI Infrastructure

December 11, 2023

Google ran out of monikers to describe its new AI system released on December 7. Supercomputer perhaps wasn't an apt description, so it settled on Hypercomputer Read more…

China Is All In on a RISC-V Future

January 8, 2024

The state of RISC-V in China was discussed in a recent report released by the Jamestown Foundation, a Washington, D.C.-based think tank. The report, entitled "E Read more…

Intel Won’t Have a Xeon Max Chip with New Emerald Rapids CPU

December 14, 2023

As expected, Intel officially announced its 5th generation Xeon server chips codenamed Emerald Rapids at an event in New York City, where the focus was really o Read more…

IBM Quantum Summit: Two New QPUs, Upgraded Qiskit, 10-year Roadmap and More

December 4, 2023

IBM kicks off its annual Quantum Summit today and will announce a broad range of advances including its much-anticipated 1121-qubit Condor QPU, a smaller 133-qu Read more…

  • arrow
  • Click Here for More Headlines
  • arrow
HPCwire