Unfortunately, not all chemicals can be our friends!
We are reminded daily of the need to decrease carbon dioxide emissions, and that we can personally take action by getting rid of our cars, carpooling, taking public transit, eating locally grown foods, and so on. Why do we need to adjust our personal lifestyles when it comes to carbon dioxide? Because carbon dioxide is a key greenhouse gas. Carbon dioxide is THE key greenhouse gas! However, there are other greenhouse gases that are key players. Angela Hong, Cora Young and collaborators at the University of Toronto and Ford Motor Company in Michigan have discovered that perfluorotributylamine (PFTBA) can cause 7,100 times more of a greenhouse gas effect than carbon dioxide. Their recent publication in Geophysical Research Letters suggests that an entire class of man-made chemicals, perfluoroalkylamines (PFAms), used in electronic applications by companies such as 3M, must be further scrutinized by scientific researchers and governments as potentially important greenhouse gases.
Why are greenhouse gases important? In a nutshell, greenhouse gases are chemicals in the atmosphere that trap the Earth’s heat. This is analogous to how a greenhouse traps heat, hence the terms “greenhouse effect” and “greenhouse gases”. The greenhouse effect is a natural process, and natural greenhouse gases include water and carbon dioxide. Unfortunately, human industrial activities over the past couple of centuries have steadily increased global atmospheric levels of carbon dioxide by about 40% based on reported pre-industrial amounts of carbon dioxide by the Intergovernmental Panel on Climate Change (IPCC) and measurements by the National Oceanic and Atmospheric Administration (NOAA). The unnaturally high rate of carbon dioxide emissions has led to a persistent rise in the average global temperature (aka global warming) and negatively impacts Earth’s environment by contributing to climate change.
Is carbon dioxide the only greenhouse gas we should be concerned about? Should you stop worrying about greenhouse gases once you get rid of your car? To top off the growing carbon dioxide problem, humans have also introduced a number of man-made chemicals into the atmosphere that could be important greenhouse gases. The electrical insulator sulfur hexafluoride is reported by the IPCC to be the most potent greenhouse gas with a global warming potential of 23,500. That means sulfur hexafluoride is 23,500 times more effective at global warming than carbon dioxide. Ms. Hong, Dr. Young and co-workers estimate that PFTBA has a global warming potential of 7,100. Should we care about the greenhouse effect of PFTBA given that its global warming potential and atmospheric concentration are about 30% of those for sulfur hexafluoride, not to mention the measured concentration of PFTBA is about 20 million times less than it is for carbon dioxide in the atmosphere?
Unlike carbon dioxide, there are no loss processes for both sulfur hexafluoride and PFTBA in Earth’s lower atmosphere. Both sulfur hexafluoride and PFTBA exist in the atmosphere for an extremely long time, for 3200 years and 500 years respectively. PFTBA is only one member of the PFAm class of chemicals. Other PFAms may be emitted into the atmosphere at similar rates as PFTBA and could also have substantially long lifetimes in our atmosphere. Ms. Hong, Dr. Young and co-authors wrote that “two other PFAms, perfluorotripropylamine and perfluorotripentylamine, are on the EPA [United States Environmental Protection Agency] list of HPV [high production volume = more than 1 million pounds per year] chemicals and may be present in the atmosphere at levels similar to that of PFTBA.” The PFAm class of chemicals as a whole have the potential to be influential greenhouse gases despite their low measured amounts, because they are so long-lived and continue to be produced in high volumes.
There is currently much that is unknown about PFAms and their potential influence on global warming. We need the government to require that companies, like 3M, share pertinent information about these chemicals, and we need industry and industry-independent scientific researchers to answer a number of questions, such as:
- What specific, and how many, PFAms are being produced and imported?
- How long will they remain in the atmosphere?
- What are their global warming potentials?
- What are their atmospheric concentrations?
Sure, we should make lifestyle changes to decrease our personal contributions to carbon dioxide emissions, but we should also be aware that the fight for our environment does not stop there. Hopefully, we can make steady improvements to Earth’s environment by getting answers to the right questions.
Original published scientific article can be found here.