Kin Yung 發問於 科學及數學化學 · 1 十年前

easy question! please help

explain why the destruction of ozone layer will cause harmful effects to human being

please also write down the web sites if you are find in the internet

1 個解答

  • 1 十年前

    The term ozone depletion is used to describe two distinct but related observations: a slow, steady decline of about 3 percent per decade in the total amount of ozone in Earth's stratosphere during the past twenty years; and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period. The latter phenomenon is commonly referred to as the ozone hole.

    The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the most important process in both trends is believed to be catalytic destruction of ozone by atomic chlorine and bromine. The main source of these halogen atoms in the stratosphere is photodissociation of chlorofluorocarbon (CFC) compounds, commonly called freons, and of bromofluorocarbon compounds known as halons. These compounds are transported into the stratosphere after being emitted at the surface. Both ozone depletion mechanisms strengthened as emissions of CFCs and halons increased.

    CFCs, halons and other contributory substances are commonly referred to as ozone-depleting substances (ODS). Since the ozone layer prevents most harmful UVB wavelengths (270–315 nm) of ultraviolet light (UV light) from passing through the Earth's atmosphere, observed and projected decreases in ozone have generated worldwide concern leading to adoption of the Montreal Protocol banning the production of CFCs and halons as well as related ozone depleting chemicals such as carbon tetrachloride and trichloroethane (also known as methyl chloroform). It is suspected that a variety of biological consequences such as increases in skin cancer, damage to plants, and reduction of plankton populations in the ocean's photic zone may result from the increased UV exposure due to ozone depletion.

    Contents [hide]

    1 Ozone cycle overview

    2 Observations

    2.1 Chemicals in the atmosphere

    2.1.1 CFCs in the atmosphere

    2.2 Verification of observations

    3 The ozone hole and its causes

    3.1 Interest in ozone hole

    4 Consequences of ozone depletion

    4.1 Increased UV

    4.2 Biological effects of increased UV

    4.2.1 Effects on Humans

    4.2.2 Effects on Crops

    4.2.3 Effects on Plankton

    5 Public policy in response to the ozone hole

    6 Current events and future prospects of ozone depletion

    7 History of the research

    7.1 The Rowland-Molina hypothesis

    7.2 The Ozone Hole

    8 Controversy regarding ozone science and policy

    9 Misconceptions about ozone depletion

    9.1 CFCs are "too heavy" to reach the stratosphere

    9.2 Manmade chlorine is insignificant compared to natural sources

    9.3 An ozone hole was first observed in 1956

    9.4 If the theory were correct, the ozone hole should be above the sources of CFCs

    10 World Ozone Day

    11 See also

    12 References

    12.1 Nontechnical books

    12.2 Technical books

    12.3 Books on public policy issues

    12.4 Research articles

    13 External links