Atmosphere around us on this planet is divided into five layers:

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
• Exosphere

The ozone layer is found at about 15 – 30 km above the Earth’s surface, in the stratosphere. It is a  naturally occurring gas which protects all life on earth from harmful ultra violet rays from the sun.

Due to our common usage of Chlorofluorocarbons (CFCs) in our recent past, we have a legacy of harm inflicted on the ozone layer.

An article explaining the finding and explanation of the damage to the ozone layer tells us:

A hole in the ozone layer, covering an area larger than the Antarctic continent, was discovered in 1985 by Joe Farman and his colleagues on the British Antarctic Survey. They discovered a general thinning over the whole globe – a 3% decrease since 1969, but with greater depletions in middle and higher northern latitudes in winter. Every winter the ozone layer was thinning by up to 8% over Europe.

You can observe daily incoming data and view annual charts on the Antarctic’s ozone layer and ozone hole on this NASA website.

The largest the hole has become so far was recorded on 24 September 2006 at 29.6 million km².  The 2014 mean ozone hole size was 20.9 million km².

Why the Antarctic?

In some areas the ozone layer has deteriorated by 20%, but above the Antarctica, this can be up to 65%!  Since about 90% of the chlorine in the atmosphere was emitted by industrialized nations, you would expect that any hole would be over one of those countries!  However, ozone depleting chemicals (ODCs) are non-reactive which means that they can remain in the atmosphere for decades.  It is only when they are hit by UV light in the stratosphere that they break apart and do their damage.  By this stage they may be in totally different places from where they began.  The extreme lower temperatures in the Antarctic can speed up the rate at which the CFCs are converted into chlorine.

Antarctica is the coldest place on earth – at times colder than Mars!  During the winter time, the sun doesn’t rise over the continent, while temperatures can drop below minus 78 degrees centigrade for up to six months.  This extreme cold is responsible for the formation of special ice clouds known as “polar stratospheric clouds” on the surface of which chlorine gas is created.  Though chlorine is stable and does not react with ozone, it is easily broken down by UV light into chlorine radicals, which break down ozone.   

When temperatures rise in the spring, ozone depleted air that had been concentrated over Antarctica moves over other countries in the southern hemisphere such as Australia, New Zealand, and South America.

At times there is also a smaller hole over the Arctic but the colder temperatures necessary for the formation of the polar stratospheric clouds may only last a month or two.  However experts have found concentrations of chlorine there 50 times greater than expected. A rare and record ozone hole  formed over the Arctic in March 2020. An opening in the ozone layer appears each spring over the Antarctic, but the last time this phenomenon was seen in the north was in 2011.

In order to safely dispose of these harmful chemicals, countries have had to implement hazardous waste treatments.

One of the most well known refrigerant gases has the DuPont brand name Freon.

it has only been since 2017 that new cars in the UK have to use a replacement gas for their air conditioning unit. But anyone with a car built before that date will need to use the ozone damaging gas, Freon R134a.

As of 2017, a new type of air conditioning gas is required by law for all new vehicles.

The gas, called HFO-1234yf, replaces previous refrigerants, as it produces 98% fewer climate-damaging pollutants than its predecessor, R134a. 

On this website, tests are being reported on the new gas.

From 2017, a change in the law required the introduction of a new refrigerant – HFO-1234YF (also known as R-1234YF) – in air-conditioning systems of vehicles, replacing the widely used R134a. This has implications for automotive engineers and HVAC technicians, particularly when it comes to using appropriate gas leak detectors.

What has led to the switch?

The move to HFO-1234YF as a refrigerant for automotive air-conditioning is required by law, as set out in European Directive 2006/40/EC, published all the way back on 17th May 2006. Due to concerns about the polluting potential of vehicle air conditioning and the newly adopted Kyoto Protocol on climate change, this directive set out a number of requirements for vehicle air-con.

Notably, these included limiting polluting refrigerants with a global warming potential (GWP) over 150, retrofitting air conditioning systems, and, most importantly, banning the sale of new vehicles with air conditioning systems using a refrigerant with a GWP over 150 from 1st January 2017, effectively outlawing R134a.

Awareness of this important subject is just one of the areas the citizens of this world require assistance in order to responsibly replace their existing air conditioning systems in cars made before 2017, to accommodate the recommended HFO-1234YF. As the climate warms, more and more people will require cars and home to be cooled by their air conditioning, but if they use old stocks of R134a they will risk damaging the ozone layer.

Solutions to this crisis have been slow in coming. Manufacturers are legally required to adapt their products but this has economic implications and that is why it has taken 11 years for the rules to change just in Europe.

We do not have time to prevaricate in this way.

Here the EPA explain about refrigerants:

What are the environmental concerns associated with the disposal of refrigerated household appliances?

Refrigerant: Household refrigerators and freezers manufactured before 1995 typically contain chlorofluorocarbonchlorofluorocarbonA compound consisting of chlorine, fluorine, and carbon. CFCs are very stable in the troposphere. They move to the stratosphere and are broken down by strong ultraviolet (UV) light, where they release chlorine atoms that then deplete the ozone layer. CFCs are commonly used as refrigerants, solvents, and foam blowing agents. The most common CFCs are CFC-11, CFC-12, CFC-113, CFC-114, and CFC-115. The ozone depletion potential (ODP) for each CFC is, respectively, 1, 1, 0.8, 1, and 0.6. A table of all ozone-depleting substances (http://www.epa.gov/ozone/science/ods/index.html) shows their ODPs, global warming potentials (GWPs), and CAS numbers. CFCs are numbered according to a standard scheme (http://www.epa.gov/ozone/geninfo/numbers.html). (CFC) refrigerant. Many window air-conditioning units and dehumidifiers contain hydrochlorofluorocarbon (HCFC) refrigerant. CFCs and HCFCs are ozone-depleting substances (ODSODSA compound that contributes to stratospheric ozone depletion. ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform. ODS are generally very stable in the troposphere and only degrade under intense ultraviolet light in the stratosphere. When they break down, they release chlorine or bromine atoms, which then deplete ozone. A detailed list (http://www.epa.gov/ozone/science/ods/index.html) of class I and class II substances with their ODPs, GWPs, and CAS numbers are available.) that, if released to the environment, destroy the ozone layer. Moreover, CFC and HCFC refrigerants are also potent greenhouse gases. Their release contributes to global climate change.

We have a massive uphill struggle to CLEAN UP our environment after innocently using CFCs extensively. We must each take personal responsibility for assisting in locating any such items which may still be found littering our home environments. We must get them to the government provided hazardous waste disposal sites as soon as possible.

Here is another extract from the EPA:

The ozone molecule (O₃) is harmful to air quality outside of the ozone layer.

Ozone can be “good” or “bad” for health and the environment depending on where it’s found in the atmosphere. Stratospheric ozone is “good” because it protects living things from ultraviolet radiation from the sun. Ground-level ozone, the topic of this website, is “bad” because it can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma. Learn more about ground-level ozone.

The above picture, headline and extracts below are found here.

Ground level ozone has been found to have a harmful reaction with particles off tyres which have been enhanced with 6PPD.

6PPD: one of several p-phenylenediamine (PPD) additives used in rubber materials, is an organic chemical used as an antiozonant and antioxidant in the rubber industry. It is used almost universally in the manufacture of tires to help them last longer and resist cracking, but is also found in other products such as the seals of pressure cookers, conveyor belts, hoses, and cables.

An article by Erik Stokstad, Dec. 3, 2020 , in online journal Science published breakthrough findings explaining the previous mystery of deaths of coho salmon in the U.S. Pacific Northwest. Researchers led by Kolodziej report the primary culprit comes from a chemical widely used to protect tires from ozone, a reactive atmospheric gas.

This is now named 6PPD-quinone .

Looking at the likely reactions suggested a breakdown product of N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine, or 6PPD. 6PPD can comprise up to 2% of vehicle tyres, being added to help stop the rubber degrading in reactions with ground-level ozone. 6PPD, whose formula is C₁₈H₂₄N₂, reacts with ozone to make a substance with a formula of C₁₈H₂₂N₂O₂, which the team calls 6PPD-quinone. The team then checked waters from Los Angeles and San Francisco, and found 6PPD-quinone in them too.

A manufacturer proudly describes their product: rubber antioxidant IIRCO 6PPD has got an excellent property of protection against fatigue and flexible cracking.

But researches have only this year reported:

Particles that erode from tires wash into streams used by coho salmon.

For decades, something in urban streams has been killing coho salmon in the U.S. Pacific Northwest. Even after Seattle began to restore salmon habitat in the 1990s, up to 90% of the adults migrating up certain streams to spawn would suddenly die after rainstorms. Researchers suspected the killer was washing off nearby roads, but couldn’t identify it. “This was a serious mystery,” says Edward Kolodziej, an environmental engineer at the University of Washington’s (UW’s) Tacoma and Seattle campuses.

Online today in Science, researchers led by Kolodziej report the primary culprit comes from a chemical widely used to protect tires from ozone, a reactive atmospheric gas. The toxicant, called 6PPD-quinone, leaches out of the particles that tires shed onto pavement. Even small doses killed coho salmon in the lab. “It’s a brilliant piece of work,” says Miriam Diamond, an environmental chemist at the University of Toronto. “They’ve done a tremendous job at sleuthing out a very challenging problem.”

Manufacturers annually produce some 3.1 billion tires worldwide. Tire rubber is a complex mixture of chemicals, and companies closely guard their formulations. Because tire particles are a common component of water pollution, researchers have been examining how they affect aquatic life.

After Kolodziej arrived at UW’s Center for Urban Waters in 2014, he joined the effort to solve the coho salmon mystery. The group created a mixture of particles from nine tires—some bought new, others provided by two undergraduates who moonlight as mechanics—to mimic what might wash off typical highways. They found several thousand unidentified chemicals in the mixture. Postdoc Zhenyu Tian spent more than 2 years narrowing down the list, separating the molecules based on their electrical charge and other properties. By May 2019, he had narrowed the focus to about 50 unknown chemicals, and then further work revealed the chemical formula of a prime suspect. “If you’re looking for an unexplained toxicant that’s killing fish, we had the perfect instruments and expertise,” Kolodziej recalls.

But what was it? A 2019 report from the Environmental Protection Agency on chemicals in recycled tires mentioned 6PPD, which has a similar formula. The final clue was buried in an industry report from 1983, which contained the exact formula of 6PPD-quinone, the molecule created when 6PPD reacts with ozone. The team synthesized 6PPD-quinone and found it was highly lethal to coho salmon.

Now, the team is working to understand how the chemical kills fish. Kolodziej and colleagues say other species of fish should also be evaluated for sensitivity. Because you can’t buy the molecule, Kolodziej’s team is making it. “My lab might even be the only place that actually has this,” he says.

The researchers suspect the compound is present on busy roads everywhere. They’ve found it washes off pavement and into streams in Los Angeles and San Francisco, for example. The simplest solution might be for tire manufacturers to switch to an environmentally benign alternative. But Sarah Amick, vice president of environment, health, safety, and sustainability at the U.S. Tire Manufacturers Association, says it’s too early to discuss alternatives. “It’s important that additional research be done to validate and verify these results.”

Another way to protect salmon is to filter stormwater through soil, but installing enough infiltration basins to treat road runoff before it reaches spawning streams would be very expensive, says co-author Jenifer McIntyre, an ecotoxicologist at Washington State University’s Puyallup Research and Extension Center. In the meantime, Kolodziej says he “can’t walk along a street without staring at all the skid marks,” thinking about tire chemicals, and “wondering what’s there.”

Whilst no quick solution is being invented by our science community, death is certain for life in streams where road runoff carrying 6PPD-quinone is arriving. What use are trips to Mars costing billions if we cannot solve these daily contamination problems?

And another tragic finding but one with a happy ending by 2021:

Humans Accidentally Created a Death Trap for Bald Eagles

Now, in an extraordinarily exhaustive new study, scientists have pinpointed the cause of death for those bald eagles in Arkansas. No wonder the mystery took 25 years to solve: The birds died because of a specific algae that lives on a specific invasive water plant and makes a novel toxin, but only in the presence of specific pollutants. Everything had to go right—or wrong, really—for the mass deaths to happen. This complex chain of events reflects just how much humans have altered the natural landscape and in how many ways; unraveling it took one scientist the better part of her career. “It’s just an amazing story,” says Gregory Boyer, a biochemist at the SUNY College of Environmental Science and Forestry, who was not involved with the study.

Susan Wilde, an aquatic scientist at the University of Georgia and a lead author on the new study, began looking into the mysterious deaths in 2001. By then, the cause of death had a name, at least—avian vacuolar myelinopathy, or AVM, which refers to empty spaces or vacuoles found in the brains of these dead birds. This brain damage is why the afflicted bald eagles seemed blind and uncoordinated.

Man-made lakes were filling with an invasive plant called Hydrilla verticillata.

Wilde had written her doctoral dissertation about one of the lakes before it was invaded by hydrilla; she returned to find dense mats of the hardy plants.

They could thrive in the man-made lake, whose waters were too nutrient-poor for native species. She saw spots on their leaves too, which she investigated under a fluorescent microscope. “The light shone down on the leaves and I said, Wow, the leaves are covered with this species I’ve never seen before,” Wilde told me. She recognized the spots as a new species of cyanobacteria, or blue-green algae, and she immediately thought they had to be important. This was 2001.

A series of experiments began to confirm her hunch. Ducks or chickens in the lab fed hydrilla without the cyanobacteria did just fine. Those fed hydrilla with the cyanobacteria got brain lesions like the eagles.

The conditions that led to the original eagle deaths—a man-made lake, an invasive plant, bromine pollution—were an accidental confluence of many human choices that engineered the environment. 

Bromine found its way into the lakes that

 could be from coal plants that use bromine to remove mercury or, ironically, from herbicides used to kill the invasive hydrilla.

But a solution was forthcoming after 25 years of mystery and dogged work from researchers to find out how AVM was occurring and leading to terrible deaths of smallest to largest wildlife using the 10 lakes.

The solution:

In Arkansas, where this all started, biologists stocked DeGray Lake with sterile grass carp, as well as a fly native to Pakistan whose larvae eat hydrilla. Those measures, along with a yearslong drought, wiped out the hydrilla completely. Bald eagles there are no longer afflicted by AVM. And bald eagles across the country are no longer endangered, thanks to decades of conservation efforts including the elimination of *DDT. Scientists are now trying to restore the native vegetation at DeGray Lake, this time without hydrilla and its associated toxin-producing cyanobacteria.

*DDT link to increasing polio cases see https://youtu.be/rZMn7oapJD4

This bumper sticker was an attempt to warn people of the dangers