EDUCATION (CBSE/UGC NET)

Detailed explanation-1: -In Antarctica where the ozone hole phenomenon is predominantly observed, the total column ozone level of less than 220 Dobson Units due to catalyzed ozone loss from chlorine and bromine compounds. For these reasons, NASA uses 220 Dobson Units as the boundary of the region representing ozone loss.

Detailed explanation-2: -The Dobson Unit is a way to describe how much ozone there would be in the column if it were all squeezed into a single layer. The average amount of ozone in the atmosphere is roughly 300 Dobson Units, equivalent to a layer 3 millimeters (0.12 inches) thick-the height of 2 pennies stacked together.

Detailed explanation-3: -The average amount of ozone is around 300 Dobson units which means 3mm thick ozone. The ozone layer is a layer of the Earth’s atmosphere in which the concentration of ozone gas is relatively high. This layer absorbs 93-99% of the sun’s high-frequency ultraviolet light, which is harmful to life on Earth.

Detailed explanation-4: -Ground-level ozone (O3), also known as surface-level ozone and tropospheric ozone, is a trace gas in the troposphere (the lowest level of the Earth’s atmosphere), with an average concentration of 20–30 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas.

Detailed explanation-5: -Ozone depletion can cause increased amounts of UV radiation to reach the Earth which can lead to more cases of skin cancer, cataracts, and impaired immune systems. Too much exposure to UV is believed to be contributing to the increase in melanoma, the most fatal of all skin cancers.