Estimation of Skin and Ocular Damage Avoided in the United States through Implementation of the Montreal Protocol on Substances that Deplete the Ozone Layer.

Sasha Madronich,Robert Landolfi,Julia M Lee-Taylor,Mark Wagner,Jessica Kyle,Zeyu Hu

doi:10.1021/acsearthspacechem.1c00183

Abstract

Overexposure to ultraviolet (UV) radiation is a threat to human health. It can cause skin cancer and cataracts. Human-made ozone-depleting substances (ODSs) reduce the ozone concentration in the Earth's stratosphere, which acts as a protective shield from UV radiation. To protect and restore the ozone layer, the Montreal Protocol on Substances that Deplete the Ozone Layer was enacted in 1987 to phase out the production and consumption of certain ODSs and was later amended and adjusted to significantly strengthen its requirements. The United States Environmental Protection Agency (EPA) uses its Atmospheric and Health Effects Framework (AHEF) model to assess the adverse human health effects associated with stratospheric ozone depletion and the U.S. health benefits from the global implementation of the Montreal Protocol. Comparing the Montreal Protocol as amended and adjusted with a scenario of no controls on ODSs showed the prevention of an estimated 443 million cases of skin cancer and 63 million cataract cases for people born in the United States between 1890 and 2100. In addition, 2.3 million skin cancer deaths are avoided. Compared with the original 1987 Montreal Protocol, strengthening the Montreal Protocol, through its subsequent amendments and adjustments, resulted in an estimated 230 million fewer skin cancer cases, 1.3 million fewer skin cancer deaths, and 33 million fewer cataract cases.

Highlights

Overexposure to ultraviolet (UV) radiation is a threat to human health, causing skin damage, eye damage, and effects on the immune system that may compromise health
We briefly describe the AHEF with its submodels and provide estimates of the health effects avoided in the U.S by the global implementation of the Montreal Protocol compared with unchecked ozone depletion
The average melanoma mortality modeled by the AHEF is 7 to 8% lower than the Department of Health and Human Services (DHHS) and Institute for Health Metrics and Evaluation (IHME) values and again more evenly divided between the sexes

Summary

Introduction

Overexposure to ultraviolet (UV) radiation is a threat to human health, causing skin damage, eye damage, and effects on the immune system that may compromise health. Earth’s primary protection from solar UV radiation is the stratospheric ozone layer, which absorbs these high-energy UV rays before they reach Earth’s surface. In 1974, Molina and Rowland noted that human-made chlorofluoromethanes, inert in the troposphere, release chlorine (Cl) atoms upon reaching the stratosphere and cause efficient catalytic destruction of ozone. This increases the amount of UV radiation reaching Earth’s surface, potentially causing more disease.

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