Trinidad and Tobago National Ozone Unit : October 2020

Thursday, 29 October 2020

Brochure on Ozone Layer Depletion and Skin Cancer

The Ozone Layer and Skin Cancer Webinar - NOUTT and the Trinidad and Tobago Cancer Society

The National Ozone Unit together with the Trinidad and Tobago Cancer Society hosted a Webinar highlighting the Ozone Layer and Skin Cancer.

The Ozone Layer (2-3 mm thick) in the stratosphere (50 km from earth’s surface) absorbs a large part of the Sun’s biologically harmful ultraviolet radiation. Stratospheric ozone is considered “good” ozone because of this beneficial role. In contrast, ozone formed at Earth’s surface in excess of natural amounts is considered “bad” ozone because it is harmful to humans, plants, and animals.

Stratospheric ozone is considered good for humans and other life forms because it absorbs ultraviolet (UV) radiation from the Sun (. If not absorbed, high energy UV radiation would reach Earth’s surface in amounts that are harmful to a variety of life forms.

The Sun emits three types of UV radiation: UV-C; UV-B, and UV-A.

Exposure to UV-C radiation is particularly dangerous to all life forms.

Fortunately, UV-C radiation is entirely absorbed within the ozone layer.

Most UV-B radiation emitted by the Sun is absorbed by the ozone layer; the rest reaches Earth’s surface. In humans, increased exposure to UV-B radiation raises the risks of skin cancer and cataracts, and suppresses the immune system. Exposure to UV-B radiation before adulthood and cumulative exposure are both important health risk factors. Excessive UV-B exposure also can damage terrestrial plant life, including agricultural crops, single-celled organisms, and aquatic ecosystems.

Low energy UV radiation, UV-A, which is not absorbed significantly by the ozone layer, causes premature aging of the skin.

Protecting stratospheric ozone. In the mid-1970s, it was discovered that gases containing chlorine and bromine atoms released by human activities could cause stratospheric ozone depletion. These gases, referred to as ozone-depleting substances (ODSs). Ozone depletion increases surface UV-B radiation above naturally occurring amounts. International efforts have been successful in protecting the ozone layer through controls on the production and consumption of ODSs . (https://ozone.unep.org/20-questions-and-answers)

Some more useful information links are presented below:

http://www.unep.fr/ozonaction/information/mmcfiles/7738-e-TheMontrealProtocolandHumanHealth.pdf