ODP vs GWP: Why They Are Both Important

EPA 608

ODP (Ozone Depletion Potential) vs GWP (Global Warming Potential): Why They Are Both Important

How we impact our environment entering the 21st century is going to remain a focus indefinitely. When we think of the sky we think of it as an invitation for those thought provoking questions as to what is out there, how do those clouds form, or maybe it’s something simple like where to string a hammock. Whatever comes to mind we know the sky has a lot of layers to it and some are more fragile than others. Various types of pollution can play a role in how healthy that sky really is and how long you want to lay on that hammock.

In this article we will begin to start breaking down these unique acronyms and define the key differences between ODP and GWP.  First, there is the Ozone Depleting Potential (ODP), which tells us how good the refrigerant is for the zone. This is distinct from Global Warming Potential (GWP), which is more complicated, calculated on a number of factors, and remains measurable for long periods of time. That’s why we have different ‘metrics’ like GWP 100 and GWP 20. The bottom line is that the higher the GWP the more heat the specific gas can keep in the atmosphere. Both ODP and GWP are great metrics for measuring how refrigerants can be dangerous to our environment and helps us understand why handling of refrigerants is so closely regulated. 

ODP: What is it and can I still use hairspray for my “80’s Party!”?

ODP value is basically a measurement of how damaging something is for the ozone layer. The lower this measurement, the less destructive a particular refrigerant is to the ozone layer. Back in the 80’s to 90’s the ozone was a major topic of discussion and got greater attention as the environmental movement became more mainstream. But, the stratospheric ozone is real and essential for filtering out many of the harmful ultraviolet (UV) rays of the sun.

Chemicals containing chlorine atoms would often find their way into the atmosphere and break down in the stratosphere. Chlorine, when it began to separate, would attach to ozone molecules and destroy them at an alarming rate. One chlorine molecule can destroy 100,000 ozone molecules during its atmospheric lifetime. And chlorine isn’t the only atom with this capacity. Bromine also causes significant damage. HC / Hydrocarbons, HCFC / hydrochlorofluorocarbons, CFC / chlorofluorocarbons, and other various ozone depleting substances and blends often found in air conditioning systems contain chlorine and have a destructive environmental impact based on scientific assessment of ozone depletion.

So why are Chlorine and Bromine so dangerous? We don’t need to get into the nitty gritty details but let’s look at real-world examples: 

Chlorine has long been used in destroying biological cells as it attaches to water quite well. Yes, it’s used in pools, but have you read that warning label on the bottle of pool shock? You know that thing that says “don’t inhale” because of toxicity? An important warning you will want to follow. There was a reason chlorine gas was weaponized as a harsh chemical weapon. It’s not safe stuff.

Bromine isn’t much different in that sense. You’ll often find Bromine used heavily in pesticides as inhalation of bromine is fatal to most animals, including humans.

In short, you can use your hairspray to really set the place ablaze (figure of speech, don’t really set anything on fire). But the items available now don’t have the same destructive properties like they did in the 80s.

GWP: The hottest club of 2023 can absolutely get hotter

As GWP values continue to be evaluated, as it has for several hundred years now, we are collectively and slowly causing that atmosphere to become warmer. Is it causing the ice caps to melt? Not a simple answer to that, but I can tell you that it is causing the air in the atmosphere to become warmer. Let me explain:

The buildup of smog in the troposphere is causing sunlight to be reflected back into the layers of the atmosphere. This in turn is causing the heat generated by radiation to become trapped between the earth and the troposphere. It also doesn’t allow all the heat to transfer from the upper layers to the ground and bounces that heat back into the upper layers of the atmosphere. In part, the smog, and other various greenhouse gas, insulate and create a ‘greenhouse’ effect. HFC / hydrofluorocarbon, HFO / hydrofruoroolefin, methane, propane, and other emissions can greatly affect climate change variables like GWP.

Before COVID, there were stories of all the smog in various countries. Red skies in India and China were photographed as a result of smog that had blocked out a high concentration of natural, unfiltered sunlight. On a smaller scale, smoke from forest fires has a similar effect. Air quality is reduced, sunlight is limited, and the smog/smoke insulates keeping the heat contained in a smaller area.

So What’s the point?

Ah, lovely reader, thank you for asking.

The point is, that these are two of the best known measurements we have, at this time, for monitoring significant changes to our atmosphere and air quality. When it comes to refrigerants in particular, these are the main two measurable categories of pollution that are taken into consideration. With advancements in science, there may become additional measurements worth consideration. You can learn more about this in our EPA 608 class on thetrainingcenter.com. Here you will learn about all the various refrigerants and the phase out - or phase down - of refrigerants as well as current Environmental Protection Agency requirements.

These two measurements have also led to major advancements in efficiency. That’s right, it saves you money! In an effort to reduce ODP and GWP, new systems have been created to use less of the necessary harmful pollutants. New advancements since the Montreal Protocol have been made to also reduce the amount of electricity used, which the generation of can also lead to ozone depletion and have measurable GWP. So, you can thank that 40 mpg car, efficient heat pump, and lower energy price on the advancements made in an effort to curb these pollutants.