OZONE and the ENVIRONMENT

Just what is Ozone? Ozone is a form of oxygen with a different chemical property Ozone differs from oxygen: Has a distinctive odor Contains 3 oxygen atoms Absorbs damaging ultraviolet (UV) radiation In large concentrations ozone is hazardous

Earth’s Atmosphere Troposphere start on the surface and extends 5 – 9 miles Air most dense All weather occurs is this region Stratosphere extends for 31 miles Contains the Ozone layer

Composition of the Atmosphere Nitrogen 78% Oxygen 21% Argon 1% Water Vapor 0 – 7% Ozone 0.01% Carbon Dioxide 0.01 – 0.1%

Ozone’s Primary Function Block or absorb most of the suns ultraviolet rays Approx. 3,000 million tons of ozone in atmosphere If concentrated at sea level, would measure only 3 mm thick Depletion of this protective shield allows too much UV radiation to strike earth

Measuring the Ozone Layer In 1920 Gordon Dobson began researching the ozone layer and its effects Dobson Unit – Measures intensity of light passing through ozone layer thus measuring it’s density – 300DU is highest level of protection

Destruction of the Ozone Layer Ozone is both created and destroyed by the action of UV rays on oxygen molecules Chlorine has been found to be major cause of ozone depletion. UV rays react with chlorine and cause a chain reaction. One chlorine molecule can destroy 100,000 ozone molecules

Satellite image of ozone hole (pink area) over Antarctica, 9-25-95

Chlorofluorocarbons (CFC) CFCs invented by Dupont, trade name Freon in 1928 Nonflammable, nontoxic, stable, non corrosive, odorless, low boiling point Used as refrigerants, in manufacturing processes, as cleaning solvents, as propellants in aerosol cans

Chlorofluorocarbons (CFC) Throughout the 60’s & 70’s scientists learned that CFCs can stay airborne for decades. Taking as much as 8 – 10 years to reach the stratosphere In the stratosphere CFCs are broken down by UV rays. Chlorine & fluorine molecules are released. Millions of tons of CFCs are currently aloft in our atmosphere, it will take several hundred years for it all to be depleted.

The Ban Begins In the late 70’s the U.S. Canada, Norway & Sweden banned CFCs in aerosol sprays 1987 Montreal Protocol signed by 150 nations, phased reduction of annual CFC releases CFC production totally banned as of Jan. 1996 If ban not in place, ozone depletion estimated to grow by .5% annually Currently hole of the size of the U.S. Size and depletion percentage varies with seasonal changes

What does this mean for me? Refrigerants used in Automobiles have changed, and may change again Strict service procedures must be followed Strict penalties for law breakers Certification programs for technicians handling refrigerants