ozone layer

Are today’s refrigerants safe?

March 21, 2025 By EarthWise Leave a Comment

Refrigeration is based on heat transfer mediums that absorb heat from the area being cooled and transfer it to the outside environment.

The earliest refrigerants were dangerous substances like ammonia. In the 1930s, chlorofluorocarbons (CFCs) like Freon became the standard refrigerant for use in refrigeration systems and even in aerosol cans. When these substances were found to be depleting the earth’s ozone layer, the Montreal Protocol dictated their phaseout and by the mid-1990s, CFCs were largely replaced by hydrofluorocarbons (HFCs).

HFCs don’t deplete the ozone layer, but they were eventually determined to be potent greenhouse gases, thousands of times more planet-warming than carbon dioxide. As a result, the global phaseout of HFCs began in 2016, and have been increasingly replaced by hydrofluoroolefins (HFOs), which are considered a more environmentally-friendly alternative to all their predecessors.

Trying to not be surprised by additional unpleasant discoveries about refrigerants, researchers are studying the potential environmental impacts of HFOs. Researchers at the University of New South Wales in Australia have found that HFOs can break down in the atmosphere and that some small amounts of the resultant products are in fact fluoroforms, which are the HFC with the greatest global warming potential and can stay in the atmosphere for up to 200 years.

That only a small amount of HFC gets into the atmosphere is good, but nevertheless it reveals that the consequences of replacing widely-used chemicals are not a simple matter to determine.

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Are our refrigerants safe? The lingering questions about the chemicals keeping us cool

Photo, posted July 19, 2021, courtesy of Vernon Air Conditioning via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Upper Atmosphere Is Cooling | Earth Wise

June 26, 2023 By EarthWise Leave a Comment

The part of the atmosphere closest to the Earth’s surface has been warming since the Industrial Revolution. This warming is associated with increasing amounts of carbon dioxide as well as other human-made chemicals that have been changing the makeup of the atmosphere. Climate change is generally thought about in terms of the lowest regions of the atmosphere – known as the troposphere – where our weather happens.

But climate models also predict that another result of the changes to the makeup of the atmosphere is that most of the atmosphere up higher will get dramatically colder. The same gases that are warming the bottom few miles of air are cooling the much greater expanses above that extend to the edge of space.

Recent satellite data has confirmed the accuracy of these models and provide further confirmation of the human fingerprint of climate change. The natural variability of weather that complicates climate models does not play a role in the upper atmosphere.

In the higher levels of the atmosphere, the effects of increasing levels of carbon dioxide are quite different. In the thinner air up there, the heat trapped and re-emitted by CO2 does not bump into other molecules creating warming. Instead, it escapes to space. Combined with the trapping of heat at lower levels, the result is a rapid cooling of the upper atmosphere.

There are potential problems associated with the cooling upper atmosphere including that it is contracting. The result is that the crowd of manmade objects in low orbit remains there longer, and there is a potential increased degradation of the ozone layer.

The changes we are making to the atmosphere are having significant effects from the surface of the earth to the edge of space.

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The Upper Atmosphere Is Cooling, Prompting New Climate Concerns

Photo, posted August 18, 2021, courtesy of Arek Socha via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The U.S. Ratifies A Climate Treaty | Earth Wise

October 14, 2022 By EarthWise Leave a Comment

In a rare display of bipartisanship, the U.S. Senate voted 69-27 in favor of ratifying a key international climate agreement aimed at curbing global warming. The Kigali Amendment to the Montreal Protocol, which has been ratified by 137 other countries so far, ends the use of climate-warming hydrofluorocarbons that are 1,000 times more potent than carbon dioxide in warming the atmosphere. This is the first international climate treaty that the U.S. has joined in 30 years.

The Kigali Agreement was established in Kigali, Rwanda in 2016 to phase out HFCs, which have been the replacements for CFCs (chlorofluorocarbons) in air conditioners and refrigerators. CFCs were found to be depleting the ozone layers that protects the earth from harmful ultraviolet rays. HFCs do not deplete the ozone layer, but they have been a significant contributor to global warming.

The U.S. ratification of the treaty is largely symbolic. The American Innovation and Manufacturing Act, passed by Congress in 2020, gave the EPA authority to regulate HFCs and the agency has already been doing so. However, the Senate action shows that the U.S. is back on the international climate bandwagon.

Failure to ratify the Kigali Amendment would have closed segments of the chemical and manufacturing industries to U.S. producers after 2023 because the Montreal Protocol prohibits trade with countries not party to it or its amendments.

Environmental advocates are hopeful that the U.S. can move forward on other climate actions. A next step would be to focus on methane, the second leading driver of climate change after carbon dioxide.

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Senate Votes to Ratify the Kigali Amendment, Joining 137 Nations in an Effort to Curb Global Warming

Photo, posted June 13, 2017, courtesy of UNIDO via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing COVID-19 Spread With UV Light | Earth Wise

November 24, 2021 By EarthWise 1 Comment

New research published by the University of Colorado Boulder analyzes the effects of different wavelengths of ultraviolet light on the SARS-CoV-2 virus. The research found that a specific wavelength of UV light is not only extremely effective at killing the virus that causes COVID-19, but also that this wavelength is safer for use in public spaces.

UV light is naturally emitted by the sun and most forms of it are harmful to living things – including microorganisms and viruses. The most harmful UV radiation from the sun is filtered out by the atmosphere’s ozone layer. Human-engineered UV light sources screen out harmful UV rays with a phosphorus coating on the inside of the tube lamps. Hospitals and some other public spaces already use UV light technology to disinfect surfaces when people are not present.

The new research found that a specific wavelength of far-ultraviolet-C, at 222 nanometers, was particularly effective at killing SARS-CoV-2, but that wavelength is blocked by the very top layers of human skin and eyes. In other words, that light has essentially no detrimental health effects for people while it is very capable of killing off viruses.

The researchers argue that this safe wavelength of Far UV-C light could serve as a key mitigation measure against the COVID-19 pandemic. They imagine systems that could cycle on and off in indoor spaces to routinely clean the air and surfaces or perhaps create an ongoing, invisible barrier between teachers and students, customers and service workers, and other places where social distancing is not practical. Installing these specialized UV lights would be much cheaper than upgrading entire HVAC systems in buildings.

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Specific UV light wavelength could offer low-cost, safe way to curb COVID-19 spread

Photo, posted January 18, 2008, courtesy of Phil Whitehouse via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Return Of An Old Threat

July 3, 2019 By EarthWise Leave a Comment

The 1987 signing of the Montreal Protocol was one of the biggest victories for global environmental stewardship. The 197 signatory nations banded together to address a planetary emergency: the depletion of the ozone layer in the upper atmosphere resulting from the use of chlorofluorocarbons or CFCs.

Over the years, there were celebratory headlines like “The Earth’s Ozone Hole is Shrinking” and “Without the Ozone Treaty, You’d Get Sunburned in 5 Minutes”. And indeed, the hole in the ozone layer has shrunk over time.

However, the presence of CFCs in the atmosphere is continually monitored and studies in recent years reported new emissions of about 13,000 tons of CFC-11 a year from somewhere in eastern Asia starting in 2012. That was two years after the 2010 date for ending all CFC production under the terms of the Montreal Protocol.

A new study published in Nature has pinned down the source of more than half of the new CFC emissions to the provinces of Shandong and Hebei on the northeastern coast of China. The bulk of these emissions are believed to come from small factories using the chemical to manufacture foam insulation used in refrigerators and buildings.

The Chinese government has already shut down two manufacturing locations, but undercover agents have found that 18 out of 21 manufacturers in the region are using the banned substance. They appear to be quite adept at circumventing enforcement.

The new emissions aren’t large enough so far to be catastrophic, but the Chinese government needs to crack down on this illegal activity. It is difficult to stop because these are small companies operating in meth lab-like facilities. Saving the earth’s atmosphere from ourselves is a tricky business.

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How an Illicit Chemical Is Jeopardizing Recovery of the Ozone Layer

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.