Jensen Hughes

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Nov 2, 2021

Last week, we attended the joint 12th meeting of the Conference of Parties (COP) to the Vienna Convention for the Protection of the Ozone Layer and the 33rd Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer. In 1985, the Vienna Convention for the Protection of the Ozone Layer was agreed upon, followed by the Montreal Protocol. In 2009, both became universally ratified becoming the first treaties in the history of the United Nations to achieve ratification by all recognized countries of the world. We have all heard of COP26 taking place right now in Glasgow – but often, many other efforts are going on behind the scenes to slow global warming. As it turns out, the very successful global efforts to protect our ozone layer are hugely important in the fight against climate change. So, how did we get here in the first place? And what is being done to protect our ozone layer?

The ozone in the stratosphere blocks ultraviolet (UV) radiation from getting to the troposphere. As a result, stratospheric ozone is sometimes colloquially referred to as “good” ozone as compared with smog and bad air quality caused by “bad” ozone in the troposphere, which is where we all live and breathe. Increased UV radiation can cause skin cancer, premature skin aging and other skin damage, cataracts, and other eye damage, suppress immune systems and even impact plants, including crops and forests.

Ozone-Depleting Substances

The problem is certain manufactured chemicals, collectively known as ozone-depleting substances, including certain firefighting agents (known as halons), which can get into the stratosphere and cause the catalytic destruction of ozone. This is sometimes referred to as the ozone hole – remember the ‘hole’ that was above Australia or the Antarctic? In reality, it’s not a hole but an overall reduction in the quantity of ozone in the whole depth of the stratosphere. To protect the Ozone Layer, the Montreal Protocol banned the production of halon and other ozone-depleting substances beginning in the 1990s. Many people can recall the transition away from chlorofluorocarbons (CFCs) – sometimes referred to their tradename of “freon” – in mobile and residential air conditioning.

Why Do We Still Use Ozone-Depleting Substances?

For us in fire and life safety, it turns out the very worst of these chemicals is the firefighting agent halon 1301. (this refers to a numbering system of the number of carbons, fluorines, chorines and bromines), With the help of the fire and life safety community, halon 1301 was the first to be banned from production by the Montreal Protocol in 1994 in developed countries and 2010 in developing countries. A big dilemma for finding new halon alternatives after the ban is that the chemistry of catalytic ozone depletion by chlorine and bromine and the chemical extinguishment of fires by chlorine and bromine looks remarkably similar. For fire extinguishment, bromine has shown itself to be many more times more effective than chlorine, hence halon’s fire extinguishment effectiveness. But it is also true for ozone depletion, where bromine is 50 times more effective in depleting ozone. Essentially, if you have chlorine or bromine in the molecule for its fire extinguishment properties, and if that molecule doesn’t break down in the troposphere, it can get into the stratosphere. That’s a massive problem for the prevention of ozone depletion.

That’s why, all these years later, there is still halon 1301 in use today in several key sectors. Nuclear power plants, oil and gas exploration, commercial shipping, civil and military aircraft and combat vehicles are all examples that the fire and life safety community continues to manage. And that is not the end of it.

What’s Next

It also turns out CFCs and halons are potent greenhouse gases with an impact thousands of times more than CO2. The production phase-out of CFCs and halons made great strides in protecting our climate, but we are doing more. One of the main halon 1301 alternatives is a high global warming hydrofluorocarbon (HFC) that is part of the overall basket of HFCs with a phase-down of production under the Montreal Protocol in the changes made by the Kigali Amendment. As this phase-down continues, we will leverage all the lessons from the halon production phase-out and ensure fire and life safety needs get met. We at Jensen Hughes have been participating in critical technology assessments used by the countries of the Montreal Protocol to make policy decisions since 1989. As we continue to monitor the developments and decisions coming out of COP26, we’ll continue to share our knowledge and contribute to the fight against climate change and halon ozone depletion.