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Do Air Conditioners Produce Ozone?

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Most people use an air conditioner, whether at home, in their car, at their workplace, or out in social settings. In fact, many people use them in all these areas of life, which means there are millions of air conditioners running every day around the world. Should we be worried about the impact on our environment? 

Air Conditioners manufactured before 2010 run using cooling fluids that do harm our ozone. These cooling fluids, chlorofluorocarbons, which are in air conditioners manufactured before 1995, and hydrochlorofluorocarbons, which are in air conditioners manufactured before 2010, negatively react with the ozone, damaging it so that the ozone cannot properly protect us from harmful ultraviolet rays from the sun. However, the Clean Air Act required these fluids to be phased out by January 2020 and replaced by chlorine-free hydrofluorocarbons. 

The rest of this article will go into greater detail about the ozone and what actions humans can take to reduce our negative impacts on our earth. 

Understanding Ozone

Ozone gas is found in two regions of the Earth’s atmosphere. The largest region is called the stratosphere in the upper atmosphere. Also known as the good ozone, it is naturally occurring and serves as a protective barrier from the harmful ultraviolet rays of the sun. Think of it as a giant sponge over the entire earth, soaking up the sun’s damaging UV-B rays that are so harmful to plants, animals, and humans. 

The lower atmospheric ozone is called the troposphere. It has the ozone layer closest to Earth and is known as the bad ozone. This ozone is created by chemical reactions when pollutants that humans and our machines release into the air react with sunlight. We see this as smog in our air. 

For every three molecules of ozone, there are 10 million molecules of air. This makes sense in the stratosphere when you consider that the air is thinner the higher up you go, so fewer oxygen atoms form ozone gas. UV rays break apart oxygen molecules, and the single oxygen atom then bonds to form ozone. 

This ozone is then split apart again by radiation and reformed back into an oxygen molecule and a single atom of oxygen. So, while ozone is constantly being created and destroyed in the stratosphere, it is destroyed much more quickly than it is created. 

Ozone Killers

This is where machines like air conditioners come into play. The older models used liquid coolants made from carbon, chlorine, and fluorine. Chlorine atoms destroy ozone molecules. In fact, just one chlorine atom can destroy 100,000 molecules of ozone. 

Given the ozone in the stratosphere exits only in small amounts, and scientifically it is much easier to destroy than to create ozone, releasing anything into the air that speeds this destructive process up is not good. Not to mention the fact that stratospheric chlorine can remain in the atmosphere for 100 years so it can continue to eat up ozone molecules for an entire generation or more.  

The Clean Air Act

Fortunately, scientists recognized this dangerous situation more than 40 years ago, and legislation under the Environmental Protection Agency and the Clean Air Act now control harmful emissions like chlorofluorocarbons. As of January 2020, air conditioners can no longer contain harmful ozone-destroying refrigerants and all new air conditioners meet these emission requirements to help keep our environment safe both now and for our future. 

Final Thoughts

From a technical standpoint, older air conditioners using liquid coolant that produce chlorine as a byproduct do produce dangerous ozone. As of January 2020, air conditioners are required to be in compliance with EPA safe operating requirements. Continuing to run an air conditioner that is not compliant can result in large fines. You have three choices: 

  • Recharge your unit with a chlorine-free refrigerant
  • Retrofit your unit so that it uses an environmentally friendly refrigerant that will not release harmful ozone-destroying chlorine into the air. 
  • Replace your old unit with a new EPA approved unit. 

If you decide to replace your unit, be aware that you can’t just throw it in the garbage. Because it is considered a hazardous waste, the EPA has specific requirements that you’ll want to be sure to follow.