Unit 1

Unit 1

1. stratosphere

   • 10-50 kms
   • air is dry. and the winds increase with height
   • temp in the lower part is about -60°C , increases with altitude
   • Ozone
     • in this layer is beneficial for us
       • protects life in earth
         • by blocking the bad effects of UV radiation from the sun
           • UV radiation bad effects
             • damages human development, degrades biological productivity, affects food pyramids, affects terrestrial and aquatic ecosystems
               • Human Health Issues:increases in certain types of skin cancers, eye cataracts and immune deficiency disorders.
             • good effects
               • stimulates the production of vitamin D in animals and people, kills pathogenic bacteria and as an air purifier, can help the treatment of skin diseases like, Psoriasis and Vitiligo
                 • ozone is used in lasers and lighting, as well as forensic analysis and viewing old scripts.
         • life is possible thanks to the ozone absorsion
     • "bad" in the troposphere
     • creation
       • interaction of solar ultraviolet (UV) radiation with molecular oxygen (O2).
         • creates the "ozone layer"
       • destruction
         • ozone depletation
           • interaction of ozone's molecules and full charged photon causing it to dissociate
           • by ozone depleting substances
             • halogen atoms from them increase the destruction of the stratosphere
               • allows ultraviolet rays to reach the earth.
             • man-made chemicals
               • used as componentes in gasses products like aerosols, gas-blown plástics, pesticides
               • example: chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), etc
             • also natural causes
               • sun-spots, stratospheric winds
     • measurement methods
       • local
         • require air to be drawn direcly into an instrument
           • absorption of UV light and electrical current from o3 chemical reactions
       • remote
         • detecting the presence of o3 at large distances away from the instrument
           • sources of UV radiation: sun and lasers
   • two types of life: bacteria and birds
   • heat control
     • greenhouse effect
       • the greenhouse gasses in the atmosphere (heat-trapping gases) absorb heat mantaining a suitable temperature for living organisms to develop
         • protects the living systems
         • later re-emitted as heat energy back to earth
       • increased concentrations of greenhouse gasses in the atmosphere lead to
         • global warming
           • mainly from human activities: deforestation, burning fossil fuels, tree-clearing, etc
           • Chemicals Involved
             • carbone dioxide, methane, halocarbons..
           • consecuencues
             • environmental effects
               • melting ice so raising seas, extreme weather, shifting rainfall, risks for wildfire
             • human health issues
               • respiratory and cardiovascular disease, injuries and premature deaths by extreme weather events, changes in the prevalence and geographical distribution of food, water-borne illnesses, other infectious diseases, threats to mental health
             • Costs for society and economy, consequences for developing countries.
         • so, by the light that dissociates the carbon from the chlorine
     • albedo effect
       • much energy from the Sun is reflected back out to space and how much is absorbed becoming heat
         • when albedo increases, more sunlight is reflected out to space, and the climate gets even cooler.