Industrial cleaning has literally evolved alongside industrial development. Such industrial progress can only be sustained by the global environment in which we live. In other words, consideration for the global environment is always necessary in the field of cleaning. What aspects of the global environment should we pay attention to? In this article, let's examine the ozone layer, greenhouse gases, and cleaning as specific examples.
Ozone is a gas consisting of three oxygen atoms. 90% of ozone present in the atmosphere exists in a thick layer in the stratosphere, 10km to 50km above the ground, and this portion is commonly called the "ozone layer". The ozone layer absorbs harmful ultraviolet radiation with wavelengths of 280nm to 315nm, and therefore plays an important role in protecting terrestrial ecosystems.
The issue that the ozone layer might be "thinning" was raised around the 1980s. At that time, chlorofluorocarbons (CFCs) were identified as one of the causes.
CFCs are a generic term for fluorocarbons, which are compounds of carbon and fluorine. Currently, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) are mainly referred to as chlorofluorocarbons.
CFCs are chemically stable and characterized by non-flammability and low toxicity. Due to their ease of handling, they were once widely used as refrigerants in refrigerators and air conditioners, cleaning agents for precision parts, foaming agents for insulation materials, and propellants for sprays.
Source: Ministry of the Environment Pamphlet "Let's Protect the Ozone Layer" 2022 Edition, p.2
CFCs themselves were not directly harmful. However, they became problematic because they contained chlorine, an element that destroys the ozone layer.
The "stable nature" of CFCs is due to their "hard-to-break structure". And this "hard-to-break structure" means they tend to persist in the atmosphere for a long time (long lifespan). CFCs that persist in the atmosphere for long periods reach the stratosphere where the ozone layer is abundant and are only decomposed when exposed to ultraviolet radiation.
When chlorine is present during this decomposition, cleavage occurs and chlorine radicals are generated. Chlorine radicals react with ozone, resulting in chain destruction of the ozone layer.
When ozone decreases (= the ozone layer becomes thinner), ultraviolet radiation reaches the ground more easily. While ultraviolet radiation has benefits for humans, such as vitamin D synthesis and bactericidal effects, it also has drawbacks. Some of these include health hazards such as skin cancer and cataracts in humans. And these effects are not limited to humans alone. They also affect plants, having broad impacts on the entire biological ecosystem.
Reference : Ministry of the Environment "Ultraviolet Environmental Health Manual 2020" P.16
The following summarizes the impacts of increased ultraviolet radiation due to ozone layer depletion.
Increased UV-B affects many organisms on land and in water, potentially changing species composition and ecosystem structure and function. Decreased primary production may reduce the capacity to absorb atmospheric carbon dioxide, potentially causing climate change.
Increased ultraviolet radiation due to ozone layer depletion causes damage to products including world heritage sites and cultural properties. Natural and synthetic materials undergo photodegradation from UVB, with damage such as discoloration and reduced strength being accelerated.
Ozone layer depletion and increased ultraviolet radiation are thought to affect air quality and biogeochemical cycles across terrestrial, aquatic, and atmospheric domains.
Reference : Ministry of the Environment " Effects of Ozone Layer Depletion on Humans and Ecosystems "
Observations of the ozone layer began worldwide in the 1960s, but in the 1980s, areas of low ozone concentration (ozone holes) were discovered over Antarctica, leading to global agreements.
In 1985, the "Vienna Convention" was adopted for the purpose of protecting the ozone layer, and in 1987, the "Montreal Protocol" was adopted as an international regulatory framework to restrict the supply of substances suspected of depleting the ozone layer.
Regarding the relationship with cleaning agents, following the adoption of the Montreal Protocol, the complete phaseout of "1,1,1-trichloroethane" and "chlorofluorocarbon (CFC)-113" was decided.
Subsequently, hydrochlorofluorocarbons (HCFCs) were newly developed as alternative CFCs, but it was discovered that their impact on the ozone layer was not zero, and "HCFC-141b" was completely phased out in 2010, followed by "HCFC-225" which was also completely phased out in 2020.
Ozone layer depletion and climate change interact with each other, and particularly the effects of ultraviolet radiation are amplified by rising temperatures. This interaction has a significant impact on the environment, making the interaction between ultraviolet radiation and climate change an important issue.
Reference : Ministry of the Environment " Effects of Ozone Layer Depletion on Humans and Ecosystems "
Like ozone layer depletion, global warming is a phenomenon that should be considered in cleaning. Global warming is a phenomenon in which temperatures on Earth rise. The cause of this phenomenon lies in greenhouse gases.
The Earth's temperature is normally maintained at a constant level through a balance between heat warmed by energy from the sun and heat radiated as infrared radiation from the heated Earth's surface. All infrared radiation from the Earth's surface would be emitted into space if there were nothing to stop it, but "greenhouse gases" absorb infrared radiation from the Earth's surface and return some of it to the surface.
When large amounts of these greenhouse gases are released into the atmosphere, their concentration increases. As the greenhouse effect that maintains temperature increases accordingly, ground temperature rises.
This is the mechanism of global warming.
Source: Ministry of the Environment
The main types of greenhouse gases mentioned above include carbon dioxide, alternative CFCs, methane, and nitrous oxide. Carbon dioxide, which accounts for the largest proportion, is familiar in our daily lives, and emissions continue to increase with industrial development.
Also, as mentioned at the beginning, industrial development and cleaning agents are closely related in terms of their use in factories and other facilities. And because certain fluorinated solvents once used in industrial cleaning due to their high oil and grease cleaning power are also included in alternative CFCs as greenhouse gases, they are not unrelated.
For greenhouse gases, there is also an index called Global Warming Potential (GWP). This is a numerical value indicating the warming capacity of other greenhouse gases based on carbon dioxide, which is the main component of greenhouse gases. Although the calculation method is not yet unified worldwide, it functions as one indicator when considering global warming.
According to values from the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, methane has 28 times, nitrous oxide has 265 times, and CFCs have warming capacities of tens of thousands of times at their highest.
As global warming progresses, it will affect not only our human lives but also entire ecosystems on Earth. In response to this situation, the following treaties and commitments have been made as international measures against global warming.
In addition to these, at the 28th Meeting of the Parties to the Montreal Protocol held in Kigali, Rwanda in 2016, countries agreed on specific reduction plans for greenhouse gases, transcending the boundaries between developed and developing countries. At this meeting, a proposal to amend the Montreal Protocol (Kigali Amendment) to add some alternative CFCs to the regulated substances was adopted, and 18 types of hydrofluorocarbons (HFCs) also used in fluorinated solvents became newly regulated.
After experiencing rapid decline from the 1980s to early 1990s, the declining trend has slowed, but total amounts continue to remain lower compared to the 1970s. The Antarctic ozone hole has not shown long-term expansion trends since the mid-1990s. While there are some increasing trends in ozone amounts over Japan, recent years continue to show trends of low total ozone.
Recovery of the ozone layer to 1960 levels is predicted to occur around 2030 in the Northern Hemisphere mid-high latitudes and around 2055 in the Southern Hemisphere mid-latitudes, but recovery in the Antarctic region is expected to be delayed. Stratospheric cooling and changes in atmospheric circulation due to climate change may affect ozone layer recovery.
As introduced so far, cleaning agents that are of concern primarily for their environmental impact are now strictly controlled by global regulations.
Among fluorinated solvents in particular, hydrofluoroethers (HFEs) and hydrochlorofluoroolefins (HCFOs) that have no impact on ozone layer depletion and do not contain chlorine molecules are receiving attention. Also, hydrofluoroolefins (HFOs), which have little impact not only on the ozone layer but also on global warming, are now attracting attention.
A stable global environment is essential for our lives. The progression of global warming has the potential to make even such living difficult. However, regarding the ozone layer, if current efforts continue, there are predictions that the Antarctic ozone hole will return to 1980s levels by the 2060s. From the above, it can be said that it is important to continue thinking about what we can do now for the future, including in the field of cleaning.
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