Ozone Hole Human Beings 2 E hv hcl

Ozone Hole & Human Beings 2

E= hv = hc/l UV is important in Vitamin D synthesis, DNA damage, … 光 子 能 量 化學鍵強度 kcal/mol UV-B UV-C UV-A 波長, nm 3

Demo (Fluorescent Dye) 100%*0. 99=99% 99%*0. 99=98. 01%*0. 99=97. 03%*0. 99=96. 06% 0. 99^10=90. 4% 0. 99^20=81. 8% 0. 99^40=66. 9% 0. 99^80=44. 8% 0. 99^160=20. 0% 5

SPF : block UV-B (sun burn) PA : block UV-A (darkening, aging) 9

O + O 2 O 3 + hv O + O 2 Net: hv heat Cl + O 3 Cl. O + O 2 10

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高度 臭氧濃度 NOAA (National Oceanic and Atmospheric Administration, USA) 12

聯合國世界氣候組織資料 World Meteorological Organization (WMO) and United Nations Environment Programme, Adapted from Nature 460, 792 -795 (2009) 13

CFC =Chloro Fluoro Carbon 氟 氯 碳 化合物 Lifetime (t) in atmosphere t = 100 yr t = 10 yr 海龍 Halon 1211 HCFC-22, 14

t = 10年 t = 100年 HCFC-22, 海龍 Halon 1211 15

But c 1, c 2, … cannot be s(Cl 2) accurately known. Pope et al. 2007 18

Cl. OOCl + hv Cl + O 2 + Cl 19

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質譜儀 Mass Detector beam source Laser s = cross section in cm 2 I = laser fluence in photons/cm 2 21

Pure Cl. OOCl sample is not available. Mass spectrum of our sample 質量 22

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Effusive beam source of Cl. OOCl 35 cm 24

Cl 2 + hn 2 Cl Cl + O 3 Cl. O + O 2 Cl. O + M Cl. OOCl + M 26

Excellent Machine Shop & Glass Shop 27

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Laser off Laser on Time 29

1990 1995 2007 30

CFx. Cl 4 -x 31

• Recent laboratory measurements of the chlorine monoxide dimer (Cl. OOCl) dissociation cross section and analyses of observations from aircraft and satellites have reaffirmed the fundamental understanding that polar springtime ozone depletion is caused primarily by the Cl. O + Cl. O catalytic ozone destruction cycle, with significant contributions from the Br. O + Cl. O cycle. 32

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額外損失的臭氧 春 Summer 秋 夏 冬 (totally dark) NASA 36