In September 1987, twenty-four countries agreed to the Montreal Protocol on Substances that Deplete the Ozone Layer, which called for countries to cut down on their use of ozone-depleting chemicals such as chlorofluorocarbons (CFCs).1 These chemicals were commonly used as coolants for air conditioning and refrigeration, propellants in aerosol spray cans, solvents and foaming agents.2 The Protocol, which has now been ratified by 197 countries, resulted in a successful reduction in global CFC usage, but these chemicals were primarily replaced by hydrofluorocarbons (HFCs), which are greenhouse gases that contribute to climate change. Confronted with growing concerns about the global consequences of climate change, almost all parties to the Montreal Protocol met again in October 2016 to pass the Kigali Amendment, which requires the phaseout of HFCs.3 Because of the terms of this amendment, industries that use CFCs and HFCs will need to start looking for specialty chemical companies that offer alternative chemicals and blends.
Identifying New Materials to Replace CFCs
Because CFCs are used in such a wide range of products, there probably won’t be just one environmentally friendly chemical that works as a replacement in every product. For example, the best alternative to include in an air conditioner may not be an equally effective foaming agent. Indeed, early studies on alternatives to CFCs and HFCs indicate that certain alternatives work better in different applications.4 Using modeling software that makes it possible to predict the chemical properties and behaviors of different materials based on their molecular structures, scientists can determine which alternatives might be best suited to each purpose.
There is also evidence that some of the proposed alternatives to CFCs and HFCs can actually make refrigerators and air conditioners more energy efficient. Although this is not a strict requirement of the Montreal Protocol, it can lower the economic and environmental costs of these products, so alternative chemicals that improve energy efficiency will be particularly appealing to manufacturers. With computer simulations, scientists can identify the most promising chemical candidates, prioritize them for development and offer them to refrigerator and air conditioning manufacturers as soon as possible.