代孕堵塞怎么办.ppt

History of the Montreal Protocol, FDA regulation of CFCs and Background to Meeting
Robert J. Meyer, MD
Director, ODE II / CDER
1
General Background
The earth’s ozone layer is a region of relatively higher ozone concentrations in the stratosphere
2
General Background
This “layer” reduces the amount of ultraviolet radiation (UV-B) reaching the surface from sunlight
As a result of ozone loss, the increased UV-B leads to increases in skin cancers (melanoma and non-melanoma), cataracts, impaired immunity
Other deleterious effects on the environment also result, as do effects on man-made substances (like plastics)
3
Development of US law, FDA regulations, and the Montreal Protocol have proceeded in overlapping timeframes, so this talk will overlap the discussions
General Background
4
1974- Work by Molina and Rowland published tying ozone depletion to stratospheric chlorine from degraded CFCs1
At that time, use of CFCs was widespread in the US
Refrigerators, A/C, foams, and in many consumer and medical aerosol products
1 – Nature, 1974; vol 249:810-812
5
1978 – In response to growing evidence of CFCs harming the ozone layer, CFCs were generally banned in spray can/aerosols by . Govt (EPA) – . hairsprays, spray paint…
FDA published 21 CFR banning use of CFCs in FDA regulated products (with essential exemptions)
6
1987 - 27 nations (including .) initiate a global ozone treaty in Montreal, known as the “Montreal Protocol on Substances that Deplete the Ozone Layer”
hereafter referred to as the “MP”
The original protocol now has over 180 signatory Parties (countries) and is regarded as the model for successful, global environmental treaties
7
Original phase-out of CFCs slated for 2000 (London - 1990)
Phase-out of CFCs is moved up to end of 1995 (Copenhagen - 1992) due to evidence of increasing ozone depletion, especially over the Antarctic (ozone “hole”)
While depletion is most prominent over southern hemisphere, the d