Ozone Layer Depletion & Solutions

By: Wai Yan Chan, Andrei Masangcay, Aleena Bacorro, and Lyzeil Escalo

Abstract 

What happens when a knight loses their shield? Or when a police officer loses their bulletproof vest? In 1985, ozone depletion was first discovered, meaning that the Earth is losing its protection as the ozone layer is damaged. What does that mean, and what are the implications?

Part 1: causes of ozone depletion- outstanding 

The stratospheric ozone layer (aka ozone layer), is a layer found in the earth’s atmosphere, a mass of protective gases attached to our planet, which is made up of ozone molecules (O3). Surprisingly, these molecules are just a trace in the gas present in the overall atmosphere. There are only about 3 ozone molecules for every 10 million molecules found in the ozone layer (National Geographic Society, 2023). 

This makes ozone prone to depletion when it comes in contact with other gas molecules (even atoms). For instance, chlorine gas acts as a major catalyst for the formation of halocarbons. In addition, the ozone layer is further depleted through the process of excessive CO2 emission (National Geographic Society, 2023 & Cataldo, 2007).

The chemicals mentioned above are the major threats to the quality of air and the ozone layer. For example, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are halocarbons that are found in most household products used, such as refrigerants, cleaning agents, foaming agents, and propellants for aerosol sprays. These products are used daily and contribute to the depletion of the ozone layer. The control of these gasses was due to the first observation of a hole in the ozone layer in 1985 by Jonathan Shanklin (Welkins, 1999 & UKRI, 2021).

The Environmental Impacts of Ozone Depletion

The ozone layer is integral to environmental health and public safety because it protects the Earth from ultraviolet (UVB) rays. Since the industrial era, the ozone layer has been depleting rapidly. It is caused by fossil fuel emissions and the use of ozone-depleting substances, such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, and methyl chloroform (Ozone, n.d.). Because of these substances, our “shield” from all the damaging radiation is dissolving. 

What will happen, then, if our shield is gone? Firstly, UVB radiation may increase the risk of skin cancer and cataracts–a clouding of the eye’s lens (Health and Environmental, n.d.). Further, UVB exposure is also the cause of the activation of certain viruses (Ozone Layer, n.d.). Therefore, depletion of the ozone layer could result in shorter lifespans, higher rates of vision loss, more disease, and an overall decrease in quality of life. 

Aside from the human costs, ozone depletion also harms the continental ecosystem. For example, UVB radiation harms plant development as plants cannot withstand the increasing radiation caused by ozone depletion. As plants are exposed to increasing levels of radiation, their capacity to adapt to environmental changes decreases. (Health and Environmental, n.d.). The changes within the plants such as the changes in plant form, the way that nutrients are distributed, the duration of developmental phases, and secondary metabolism can be detrimental to the plant species. The impact can further extend to the ecosystem as it alters the food chain. 

Similarly, in marine ecosystems, phytoplankton are essential. However, their productivity is limited by UVB radiation on the water surface. Furthermore, exposure to solar UVB radiation has been shown to affect both the orientation and mobility of phytoplankton (Health and Environmental, n.d.). The correlation between the productivity of phytoplankton and the increasing level of UVB radiation is proved by scientists (Health and Environmental, n.d.). UVB radiation can also directly impact primary consumers like fishes, shrimps, crabs, and amphibians by damaging their early developmental stages (Health and Environmental, n.d).

In summary, UVB radiation is highly detrimental, not just to humans, but to the broader environment and many other creatures as well. Elevated levels of UVB reaching the Earth's surface can lead to the onset of diseases and the impairment of critical functions in microorganisms. Hence, it can trigger the collapse of the food chain with serious consequences.

Ozone Recovery

According to the quadrennial assessment report published by the UN-backed Scientific Assessment Panel to the Montreal Protocol, the phase-out of around 99% of banned ozone-depleting substances (ODS) has been confirmed. Assuming current policies remain in place, the ozone layer is expected to recover to its 1980 levels by approximately:

- 2066 over the Antarctic region

- 2045 over the Arctic region 

- 2040 for the rest of the world

ODS alternatives 

In recent years, significant progress has been made in identifying non-ozone-depleting replacements for ODS. There are currently alternatives for refrigeration and air conditioning applications. For example, HFC-410A can replace HCFC-22, while HFC-134a can replace CFC-12. These alternate chemicals used are less harmful to the environment. Additionally, there are developing markets for "drop-in" alternatives to halons and HCFCs.

  In cleaning applications, petroleum solvents can replace CFC-113 or 1,1,1-trichloroethane. The electronics sector can also use alternate procedures like aqueous cleaning or even no-clean technology. 

Hydrocarbons, such as propane and butane, are currently used as propellants in many personal and household aerosol goods, such as paint sprays and pesticides, in place of HCFCs and CFCs. 

Conclusion 

While there have been international agreements made to address the issue and development of ODS alternatives, there are some simple actions that each person takes can have an impact. These actions include using environmentally friendly appliances and educating others to do the same. Every little bit helps, and the collective impact of individuals making sustainable choices can be significant in combating this serious environmental issue.

References

Cataldo F. (2007). Ozone reaction with carbon nanostructures. 2: The reaction of ozone with  milled graphite and different carbon black grades. Journal of nanoscience and nanotechnology, https://doi.org/10.1166/jnn.2007.327

Government of Canada (n.d.). Ozone layer depletion: health and environmental effects https://www.canada.ca/en/environment-climate-change/services/air-pollution/issues/ozone-layer/depletion-impacts/health-environmental-effects.html

Government of Hong Kong (n.d.) Ozone Layer Protection Environmental Protection Department https://www.epd.gov.hk/epd/english/environmentinhk/air/ozone_layer_protection/wn6_info_olp_ue_c.html#:~:text=Buy%20air%2Dconditioning%20and%20refrigeration

National Geographic Society (2023). Ozone Layer - National Geographic Education. 

https://education.nationalgeographic.org/resource/ozone-layer/

Tennessee State Government Department of Health (n.d.) Ozone. https://www.tn.gov/health/cedep/environmental/environmental-health-topics/eht/ozone.html

UKRI (2021). Meet the scientist who discovered the hole in the ozone layer. 

https://www.ukri.org/news-and-events/responding-to-climate-change/our-climate-pioneers/meet-the-scientist-who-discovered-the-hole-in-the-ozone-layer/#:~:text=In%201985%20Jonathan%20Shanklin%20was,it%20has%20made%20a%20difference.

UN Environment Programme. (2023, January 9). Ozone layer recovery is on track, helping avoid global warming by 0.5°C. https://www.unep.org/news-and-stories/press-release/ozone-layer-recovery-track-helping-avoid-global-warming-05degc 

U.S. Environmental Protection Agency (n.d.) Health and Environmental Effects of Ozone Layer Depletion. https://www.epa.gov/ozone-layer-protection/health-and-environmental-effects-ozone-layer-depletion

Welkins J. (1999)  Chlorofluorocarbons (CFCs) - National Oceanic and Atmospheric Administration (NOAA), Climate Monitoring and Diagnostics Laboratory (CMDL). The Chapman & Hall Encyclopedia of Environmental Science. https://gml.noaa.gov/hats/publictn/elkins/cfcs.html