Ozone Layer and the Different Health Implications

Emerging evidence has shown that both short-term and long-term exposures to ozone, at concentrations below the current regulatory standards, were associated with increased mortality due to respiratory and cardiovascular diseases. The pathophysiology to support the epidemiologic associations between mortality and morbidity and ozone centers at the chemical and toxicological property of ozone as a strong oxidant, being able to induce oxidative damages to cells and the lining fluids of the airways, and immune-inflammatory responses within and beyond the lung. Worldwide, ozone is responsible for several hundreds of thousands of premature deaths and tens of millions of asthma-related emergency room visits annually.

To combat ozone pollution globally, more aggressive reductions in fossil fuel consumption are needed to cut NO_x and VOCs as well as greenhouse gas emissions. Meanwhile, preventive and therapeutic strategies are needed to alleviate the detrimental effects of ozone especially in more susceptible individuals. Interventional trials in humans are needed to evaluate the efficacy of antioxidants and ozone-scavenging compounds that have shown promising results in animal studies.

//www.frontiersin.org/articles/10.3389/fimmu.2019.02518/full

Ozone Layer and the different health implications

Changes in the thickness of the ozone layer, which efficiently absorbs radiation in the required wavelength range, can impact the intensity of biologically active UVB radiation (280-318 nm) due to climate change, which is currently manifested in the form of global warming. Because the Montreal Protocol's requirements were met, the increase in UVB radiation outside the Antarctic ozone hole at the end of the twentieth century was negligible, which can be explained by the high variability of other (non-ozone) factors affecting this radiation, such as cloudiness and aerosols. Without the Montreal Protocol, solar UV radiation peaks at mid-northern latitudes might triple by 2065, posing significant environmental and health risks. In addition to the Montreal Protocol, greenhouse gas emissions substantially impact the ozone, resulting in a fall in stratospheric temperature and hasten circulation processes. ^[1]

Chemicals containing the halogens chlorine and bromine are responsible for ozone depletion. They are significant components of the chlorofluorocarbons (CFCs) class of refrigerants, which were widely used in the mid-twentieth century. CFCs are inert and can move to the upper atmosphere on wind currents, broken apart by the sun's ultraviolet light. These gases break down in the presence of Ultraviolet (UV) radiation, releasing chlorine atoms, catalysing ozone degradation. Ozone depletion catalysed by Cl can occur in the gas phase, but it is greatly accelerated in the presence of polar stratospheric clouds (PSCs). London in 1990, Nairobi in 1991, Copenhagen in 1992, Bangkok in 1993, Vienna in 1995, Montreal in 1997, Beijing in 1999, and Kighali in 2016 was the eight times the Protocol was amended: London in 1990, Nairobi in 1991, Copenhagen in 1992, Bangkok in 1993, Vienna in 1995, Montreal in 1997, Beijing in 1999, and Kighali in 2016. The 1990 modifications introduced twelve additional chemicals to the list of ozone-depleting substances and a new list of substances for control, including hydro Bromo fluorocarbons and methyl bromide. The Montreal Protocol is the first international convention to be ratified by every country on the planet. According to the Montreal Protocol Scientific Assessment Panel, we can expect a near-complete recovery of the ozone layer by the middle of the twenty-first century if the Protocol is implemented. ^[2]

Reference

1. Larin IK. On the Influence of Global Warming on the Ozone Layer and UVB Radiation. Izvestiya, Atmospheric and Oceanic Physics. 2021 Jan;57(1):110-5.

//link.springer.com/article/10.1134/S0001433821010096

2. AINA OA. An Appraisal of Ozone Layer Depletion and Its Implication on the Human Environment. Earth. 2019;83.

//core.ac.uk/download/pdf/234652113.pdf

//ec.europa.eu/clima/policies/ozone_en&source=gmail&ust=1632256796713000&usg=AFQjCNH9HV-qNgZ4RgRa8085PQus99uiB g"> //ec.europa.eu/clima/policies/ozone_en

In the most recent times with lockdowns and restrictions in place during COVID-19, researches in China indicate that the concentrations of primary air pollutants, such as like NO2, SO2, have sharply reduced due to large decrease of emissions. However, the changes of secondary pollutants like secondary aerosol and ozone were various, and their concentrations in some cities even increased due to the change of chemical reactions.[4]

On a background note, large ozone holes and depletion of the layer let in a huge amount of UV radiation into the earth’s atmosphere. Overexposure to UV radiation can cause a range of health effects, including skin damage (skin cancers and premature aging), eye damage (including cataracts), and suppression of the immune system. Researchers believe that overexposure to UV radiation is contributing to an increase in melanoma, the most fatal of all skin cancers.[2] On another hand, around one third of all food produced globally for human consumption is either lost or wasted each year, generating an estimated 8 per cent of total greenhouse gases per year globally. [3]

To fight this climate change disaster, the Montreal Protocol on Substances that Deplete the Ozone Layer has been standing in place to regulate production and consumption of nearly 100 chemicals referred (OSD). Since the ban on halocarbons, the ozone layer has slowly been recovering, according to WMO. [1]

Recent studies found that chlorofluorocarbons (CFCs), the main ozone-depleting gases, would have driven 2.5°C of extra warming by 2100 had they not been outlawed. The Kigali Amendment to the Montreal Protocol is aimed at bringing various climate-associated benefits while making parties to commit to phasing down hydrofluorocarbons (HFCs), potent greenhouse gases that replaced CFCs as refrigerants. Reducing their use is expected to avoid up to 0.4°C of global temperature rise by the end of the century, while continuing to protect the ozone layer.

On this World Ozone Day, the head of UNEP has called on every nation and business to work to meet the goals of the Kigali Amendment to fight greenhouse effects and ozone depletion. [3]

REFERENCES:

1. //www.downtoearth.org.in/news/climate-change/antarctic-ozone-hole-one-of-the-largest-deepest-closes-74943
2. //www.epa.gov/sites/default/files/2015-07/documents/achievements_in_stratospheric_ozone_protection.pdf
3. //ozone.unep.org/un-environment-programme-head-ozone-agreement-slows-climate-change-and-increases-food-security
4. Zhao F, Liu C, Cai Z, et al. Ozone profile retrievals from TROPOMI: Implication for the variation of tropospheric ozone during the outbreak of COVID-19 in China. Sci Total Environ. 2021;764:142886. doi:10.1016/j.scitotenv.2020.142886 //www.ncbi.nlm.nih.gov/pmc/articles/PMC7550903/#s0075title

Ozone layer absorbs a band of UV-B radiation . Ozone layer depletion , is simply the wearing out of amount of ozone in stratosphere . Unlike  pollution , which has many types and causes different health implications . Effects on human health ozone layer depletion increases the amount of UVB that reaches the Earth surface . Laboratory and epidemiological studies demonstrate that UVB causes non - melanoma skin cancer and plays a major role in malignant melanoma development . In addition , UVB has been linked to the development of cataracts , a clouding of the eye lens. Because all sunlight contains some UVB , even with normal stratospheric ozone levels , it is always important to protect your skin and eyes from sun . Protecting the ozone layer : The ozone layer must be protected . For this the use of CFC's has to be stopped . We must buy products that are labeled ozone friendly or CFC free. Substitutes for CFC's should be used . HCFC's are substitutes for CFC's . Let us all take a step ahead and save the ozone layer. Ozone is both beneficial and harmful to us . Ozone depletion can cause a variety of health problems in humans .So its our duty to protect the ozone layer. Some international convention like Vienna Convention and Montreal Protocol are of greatest success stories .

                      The climate of Antarctica has changed a lot for Ozone depletion , future will reflect both ozone recovery and GHG warming.

An indirect effect of climate change and ozone depletion is nutrition insecurity. Climate change can impact health and nutrition through decreased food quantity and access, decreased dietary diversity, and decreased food nutritional content. Studies have shown that increased temperature and elevated CO2 levels can reduce the nutritional value of some staple crops. It can additionally undermine current efforts to reduce hunger and promote nutrition and worsen the existing burden of malnutrition. Some of the negative influence of climate change in the agriculture sector includes poor crop yields, increased diseases and stress on livestock, damage to the habitats of some species of fish and increased pest damage in fruit which can potentially lead to a reduction in the food supply and increased food prices. If the prices of healthy foods increase under climate change, disadvantaged groups may not afford them and hence turn to less expensive but unhealthy foods, thus increasing their risk of lifestyle disease.

Interesting read: 

1.This paper proposes policy directions to address nutrition in the climate change agenda and recommendations for consideration by the UN Framework Convention on Climate Change Tirado MC, Crahay P, Mahy L, Zanev C, Neira M, Msangi S, Brown R, Scaramella C, Coitinho DC, Müller A. Climate change and nutrition: creating a climate for nutrition security. Food and Nutrition bulletin. 2013 Dec;34(4):533-47.

2.Sulda, H., Coveney, J. and Bentley, M., 2010. An investigation of the ways in which public health nutrition policy and practices can address climate change. Public health nutrition, 13(3), pp.304-313.

3.Macdiarmid, J.I. and Whybrow, S., 2019. Nutrition from a climate change perspective. Proceedings of the Nutrition Society, 78(3), pp.380-387.

Tropospheric ozone is a secondary gaseous pollutant produced by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). It occurs when pollutants from vehicles, industries and other sources react in presence of sunlight (1). As per the GBD report, ozone exposure led to an approximate 8·0% of global COPD mortality in 2015, with high mortality in China, India, and the USA (2). This paper discusses the present and imminent disease burden due to ambient ozone exposure in India and highlights the challenges to improve air quality related public health in India (3).

References

1. //www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics
2. //www.thelancet.com/action/showPdf?pii=S0140-6736%2817%2930505-6
3. //agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GH000168

Reduction in ozone levels is a predisposing factor to less protection from the sun’s rays and more exposure to harmful radiations such as Ultraviolet rays (UV) at the Earth’s surface. Ozone layer depletion causes the ultraviolet B rays (UVB) to reach the Earth’s surface and leads to heat stress. Depletion of stratospheric ozone layer has both direct and indirect effects on health. Direct adverse effects include increasing risk of developing non-melanoma skin cancer that can develop into malignant melanoma, cataracts, and rise in some vector and non-vector borne infections. UVB-induced immune suppression can have positive and negative consequences for a number of disease such as autoimmune and reactivation of viral diseases.

On the other hand, the direct beneficial effect is the synthesis of vitamin D and improvement in bone health and nutrition status. The indirect health effects include changes in quality and quantity of food and surface waters to be used for drinking. Increased levels of fine particulate matter and ozone are known to be associated with toxicity and higher levels of respiratory diseases.

References:

1. //www.epa.gov/ozone-layer-protection/health-and-environmental-effects-ozone-layer-depletion
2. //www.ncbi.nlm.nih.gov/pmc/articles/PMC6400464/
3. //www.nap.edu/read/9100/chapter/5#14

Ozone layer depletion has negative effects on human health such as skin cancers, eye cataract and Immune deficiency disorders. It also disrupts terrestrial and aquatic ecosystems, food chains and biochemical cycles and reduce agricultural productivity as it alters plant growth. There are actions taken to protect Ozone layer such as EU ozone regulation and Montreal protocol. Under these actions ozone depleting substances are banned such as hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs). Ozone layer is showing recovery signs but it is not expected to recover fully before second half of this century as these ozone depleting substances  linger on in the atmosphere for many years once released. Much needs to be done to protect ozone layer and further actions are required globally to ensure Ozone recovery.

Read here //ec.europa.eu/clima/policies/ozone_en

Climate change is concerned with how carbon dioxide, methane and other greenhouse gases are altering the global climate system. Ozone depletion is caused due to chlorine and bromine from industries, damaging ozone molecules. Chemicals used in refrigerants such as CFC destroys the ozone layer as they contain chlorine.  

UV-A is a low energy form of UV, UV-B causes damage to living organisms and UV-C is absorbed and never reaches the surface. UV radiation is absorbed by chromophores in the skin and penetrates deep into the dermis. UV-B radiation affects all skin types. Basal cell carcinoma is surgically removed whereas malignant melanoma is fatal. The lens and conjunctiva of the eyes are damaged by UV-B radiation and over exposure results in snow-blindness. UV-A also leads to cataract. It induces systemic immune suppression that may have adverse effects on health. 

Citation

1. Fathy R, Rosenbach M. Climate Change and Inpatient Dermatology. Curr Dermatol Rep. 2020 Aug 22:1-9. doi: 10.1007/s13671-020-00310-5. Epub ahead of print. PMID: 32864193; PMCID: PMC7442546.

2. Norval M, Lucas RM, Cullen AP, de Gruijl FR, Longstreth J, Takizawa Y, van der Leun JC. The human health effects of ozone depletion and interactions with climate change. Photochem Photobiol Sci. 2011 Feb;10(2):199-225. doi: 10.1039/c0pp90044c. Epub 2011 Jan 20. PMID: 21253670.

3. McKenzie RL, Aucamp PJ, Bais AF, Björn LO, Ilyas M, Madronich S. Ozone depletion and climate change: impacts on UV radiation. Photochem Photobiol Sci. 2011 Feb;10(2):182-98. doi: 10.1039/c0pp90034f. Epub 2011 Jan 20. PMID: 21253660.

Reference

//www.canada.ca/en/environment-climate-change/services/air-pollution/issues/ozone-layer/depletion-impacts/health-environmental-effects.html

Ozone depletion because of development of human economic activities is causing ultraviolet radiation reaching the surface of the earth with implications on human health. Ultraviolet radiations interacts with the surface and internal structures of the eye and gave rise to ocular diseases like pterygium and cataract. The skin is also exposed directly to solar ultraviolet radiations, and the development of skin cancer is the main adverse health outcome of excessive ultraviolet radiation exposure. Skin cancer is the most common form of malignancy amongst fair-skinned people, and its incidence has increased markedly in recent decades. There is one beneficial effect of solar ultraviolet radiation as well. It contributes to the cutaneous synthesis of vitamin D, which is  a crucial hormone for bone health and for other aspects of general health. 

Reference: //pubmed.ncbi.nlm.nih.gov/17344960/