4.12) Greenhouse effect

4.12 recall that water vapor, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases

UV light came from sun ---- short wavelength & high energy

50% of UV light is reflected by clouds back into space

50% is being absorbed by the earth surface in which the UV light is converted into infrared rays

infrared rays has longer wavelength and some is lost into the space by heat

Greenhouse gases = water vapour, CO2, methane (CH4)

Infrared light hits the greenhouse gas in which the energy is absorbed and spread the ray to all direction, which reemits infrared and redistribute some gases going downward. This keeps the earth warm and raise its temperature.

Enhanced greenhouse effect

If we increase CO2 and CH4, they will absorb more infrared rays which leads to increase in temperature. This can result in climate change.

CFC - Chlorofluorocarbon - effect zone layer (O3)

- Carbon

- Fluorine

- Chlorine

CCL3F -----sunlight----> CCO2F(-) + Cl(-)

notice ions formed

Cl(-) breaks O3 down into O2.... but O3 is much better in absorbing UV light. We are losing the protection of the ozone effect.

Sources of CFCs are aerosols, air conditioner, refrigeration, etc.