How do protect of ozone layer?

The ozone layer:

The ozone layer is a natural layer of gas in the upper atmosphere that protects humans and other living things from harmful ultraviolet (UV) radiation from the sun.

Although ozone is present in small concentrations throughout the atmosphere, most (around 90%) exists in the stratosphere, a layer 10 to 50 kilometers above the Earth’s surface. The ozone layer filters out most of the sun's harmful UV radiation and is therefore crucial to life on Earth.

World governments agreed in the late 1980s to protect the Earth’s ozone layer by phasing out ozone-depleting substances emitted by human activities, under the Montreal Protocol. In Europe, the Protocol is implemented through EU-wide legislation that not only meets its objectives but also contains stricter, more ambitious measures.

Global action taken under the Montreal Protocol has halted the depletion of the ozone layer and allowed it to start recovering, but much remains to be done to ensure a steady recovery.

Ozone depletion:

Scientists discovered in the 1970s that the ozone layer was being depleted.

Atmospheric concentrations of ozone vary naturally depending on temperature, weather, latitude and altitude, while substances ejected by natural events such as volcanic eruptions can also affect ozone levels.

However, these natural phenomena could not explain the levels of depletion observed, and scientific evidence revealed that certain man-made chemicals were the cause. These ozone-depleting substances were mostly introduced in the 1970s in a wide range of industrial and consumer applications, mainly refrigerators, air conditioners and fire extinguishers.

Ozone hole:

Ozone depletion is greatest at the South Pole. It occurs mainly in late winter and early spring (August-November) and peak depletion usually occurs in early October, when ozone is often completely destroyed in large areas.

This severe depletion creates the so-called “ozone hole” that can be seen in images of Antarctic ozone, made using satellite observations. In most years, the maximum area of the hole is bigger than the Antarctic continent itself. Although ozone losses are less radical in the Northern Hemisphere, significant thinning of the ozone layer is also observed, over the Arctic and even over continental Europe.

Most of the ozone-depleting substances emitted by human activities remain in the stratosphere for decades, meaning that ozone layer recovery is a very slow, long process. The hole grew in the years following ratification of the Montreal Protocol, due to the lag caused by the fact that ozone-depleting substances remain in the stratosphere for a long time. The maximum size of the ozone hole is now decreasing.

Effects of ozone depletion for humans and the environment:

Ozone layer depletion causes increased UV radiation levels at the Earth's surface, which is damaging to human health.

Negative effects include increases in certain types of skin cancers, eye cataracts and immune deficiency disorders. UV radiation also affects terrestrial and aquatic ecosystems, altering growth, food chains and biochemical cycles. Aquatic life just below the water’s surface, the basis of the food chain, is particularly adversely affected by high UV levels. UV rays also affect plant growth, reducing agricultural productivity.

Health Effects:

Increased UV levels at the earth's surface are damaging to human health. The negative effects include increases in the incidence of certain types of skin cancers, eye cataracts and immune deficiency disorders. Increased penetration of UV results in additional production of ground level ozone, which causes respiratory illnesses.

Environmental Effects:

UV affects terrestrial and aquatic ecosystems, altering growth, food chains and biochemical cycles. In particular, aquatic life occurring just below the surface of the water, which forms the basis of the food chain, is adversely affected by high levels of UV radiation. UV rays also have adverse effects on plant growth, thus reducing agricultural productivity. Furthermore, depletion of stratospheric ozone also alters the temperature distribution in the atmosphere, resulting in a variety of environmental and climatic impacts.

Economic Effects:

Increased health costs are the most important direct economic impact of increased UV radiation. The medical expenses for millions of additional cases of skin cancers and eye cataracts pose a challenge to health care systems, particularly in less developed countries. Increased UV radiation also reduces the lifetime and tensile properties of certain plastics and fibers.

Indirect economic impacts include a range of additional costs, for instance for combatting climate change or as a result of reduced fish stocks.

Impact of global action & remaining challenges:

Global consumption of ozone-depleting substances has been reduced by some 98% since countries began taking action under the Montreal Protocol. As a result, the atmospheric concentration of the most aggressive types of ozone-depleting substances is falling and the ozone layer is showing the first signs of recovery.

Nevertheless, the ozone layer is not expected to recover fully before the second half of this century. This is because once released, ozone-depleting substances stay in the atmosphere for many years and continue to cause damage.

Much remains to be done to ensure the continued recovery of the ozone layer and to reduce the impact of ozone-depleting substances on the Earth’s climate.

Maximum ozone hole extend over the Southern Hemisphere from 1979 to 2019.

Action to protect the ozone layer:

The Montreal Protocol:

In 1987, to address the destruction of the ozone layer, the international community established the Montreal Protocol on ozone-depleting substances. It was the first international treaty to be signed by all countries of the world and is considered the greatest environmental success story in the history of the United Nations.

The Montreal Protocol’s objective is to cut down the production and consumption of ozone-depleting substances, in order to reduce their presence in the atmosphere and thus protect the Earth's ozone layer.

Ozone-depleting substances are still present in many older types of equipment and appliances, so awareness of how to deal with this is crucial. Here are some practical things individuals can do to help protect the ozone layer.

Make sure that old refrigerators and air conditioners are disposed of safely by giving them to a recycling yard. Take care not to damage the cooling circuit which contains the ODS;
Ensure technicians repairing your refrigerator or air conditioner recover and recycle the old ODS, so they are not released into the atmosphere;
When renovating your house, make sure that old insulation foams containing ODS are disposed of as environmentally hazardous waste;
Inform yourself about ozone depletion through further reading, and suggest activities at your children's school to increase awareness of the problem and initiate local action.

While an increased amount of UV radiation is bad for human health, too little exposure can also have negative effects. These are mainly related to the reduced vitamin D production in the skin which is induced by UV radiation. Under-supply of vitamin D is the cause of a number of illnesses such as osteoporosis, softening of the bones, rickets or cardiovascular problems. Dark-skinned people are particularly vulnerable to a decrease in natural UV radiation. However, most people get adequate exposure to UV radiation in their daily lives. For healthy humans, there is no medical reason to seek additional exposure.

Protecting the ozone layer also protects the climate:

The reduction in ozone depleting substances has also had a beneficial side effect. Ozone-depleting substances are also very potent greenhouse gases, contributing to the phenomenon as other substances widely known to have a greenhouse effect like carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Therefore, by reducing emissions of ozone-depleting substances, the Montreal Protocol has protected both the ozone layer and the climate at the same time.

The magnitude of this benefit is substantial. The reduction in ODS emissions expected as a result of compliance with the Montreal Protocol has been estimated globally at 10-12 gigatons of CO2-equivalent between 1985 and 2010. In contrast, the reduction target of greenhouse gas emissions under the Kyoto Protocol (assuming full compliance by all developed countries) is estimated at 1-2 gigatons of CO2-equivalent on average per year between 2008 and 2012, compared to base-year emissions. The phasing out of climate-changing ODS under the Montreal Protocol has therefore avoided greenhouse gas emissions by an amount 5-6 times larger than the target of the Kyoto Protocol for 2008-2012.

ODS substitutes are now raising concerns:

The reduction of ODS emissions is not a uniformly positive story. In fact, it has indirectly led to new problems. Fluorinated gases (F-gases) have been introduced as substitutes for ODS in many sectors such as refrigeration and air conditioning applications. F-gases include hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride (SF6). These gases do not deplete the ozone layer, but they are greenhouse gases. This means that these new gases also contribute to climate change. And to make matters worse, these F-gases often have a far larger impact on the climate than 'traditional' greenhouse gases such as carbon dioxide (CO2). For example, some F-gases have a greenhouse effect that is up to 23 000 times more powerful than the same amount of carbon dioxide. Fortunately, the emissions of F-gases are far smaller than those of CO2, but the use of F-gases and their presence in the atmosphere have increased since the 1990s. As a result, the significant contribution of the Montreal Protocol to fighting climate change is in danger of being wiped out by the growing importance of F-gas emissions.

Global and European agreements to limit F-gases:

F-gas emissions are monitored under the United Nations Framework Convention on Climate Change (UNF CCC) and its Kyoto Protocol, but not currently addressed by the Montreal Protocol. Fluorinated gases presently account for about 2% of global greenhouse gas emissions. Several countries have started to take measures on F-gases, led by the European Union (EU) which has committed to reducing use of HF Cs, the most important F-gases, by 80% of today's levels by 2030.

There are two approaches to reducing F-gas emissions. The first approach is to avoid the use of F-gases completely by using gases or technologies that are less damaging to the climate. The second approach is to reduce the use of F-gases in products and equipment. The EU first set out specific policies to reduce F-gas emissions in 2006 with the so-called 2006 F-gas Regulation, and with a directive limiting F-gases used in air conditioners in cars, the so-called MAC Directive. In the absence of this legislation, F-gas emissions were projected to increase.

Considering overall emissions

Because F-gases contribute to climate change, businesses are now looking to replace them with other substances. Alternatives that do not damage the ozone layer or contribute to climate change have become available over recent years in a variety of applications such as refrigeration, air conditioning, foam blowing and aerosols. Many of these alternatives lead also to higher energy efficiency, which is important as the indirect emissions from energy use during the lifespan of a product are often considerably higher than direct emissions of F-gases.

Further work needs to be done to reduce HF Cs and ODS:

HF Cs account for 98% of F-gas emissions, and their use continues to increase even though environmentally-friendly alternatives to HF Cs exist. Measures that further limit the use and emissions of HF Cs are therefore needed.

Within the EU, ensuring a full implementation of the new F-gas Regulation (and in particular the phasing down of HF Cs that it envisages) is critically important.

And even though most ODS are being phased out, the Montreal Protocol still allows some quantities of ODS to be produced and used for certain niche applications (e.g. feedstock use). Cost-effective alternatives in these niche applications should be developed.

In addition, large quantities of ODS are still contained in old equipment (refrigeration systems and air conditioners) and buildings (foams) and will be released in to the atmosphere if not properly reclaimed and destroyed. Measures enabling the safe recovery of remaining ODS are therefore also essential.

Further information:

The EEA supports the European Commission and Member States in the annual company-based reporting of information concerning the production and use of ODS and F-gases in the European Union. The reported information is summarized in the following annual reports by the EEA:

Report on fluorinated gases
Briefing on ozone-depleting substances

The EEA also publishes two related indicators:

Indicator on production, sales and emissions of fluorinated greenhouse gases
Indicator on production and consumption of ozone depleting substances