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Ozone
Hole Reaches South America
October
20,2000-The Ozone hole has been reaching land and
population areas in Argentina, Chile and The Falkland Islands all but two days
since October 6,2000(October 9 & 10). Ozone
levels are down as much as 70% in some areas. The protective level of ozone has
dropped below 150 dobson units in some areas. It has reached further
north reaching the towns of Rio Gallegos, Puerto Santa Cruz, and Rio Grande
affecting an additional 200,000 people.
Central
Intelligence Agency Maps from University
of Texas Map Center
October
17,2000-The Ozone hole has been reaching land and
population areas in Argentina, Chile and The Falkland Islands all but two days
since October 6,2000(October 9 & 10). Ozone
levels are down as much as 45% in some areas. The protective level of ozone has
dropped below 200 dobson units in some areas. The area and population affected
including the Argentinean
city of Ushaia which has a population of 30,000 and Punta Arenas, Chile which
has a population of 120,000 are all at risk during this time period. The
public should avoid going outside during the peak hours of 11:00 a.m. and 3:00
p.m. to avoid exposure to the UV rays. If people do go outside during these
hours they should wear protective sunscreen and if possible a hat or head
covering and sunglasses with a uv rating.
For
the Second time in less than a week
Dangerous
levels of UV rays bombard Chile and Argentina
October
12,2000-The Ozone hole again reached land and
population areas in Argentina, Chile and The Falkland Islands on October 11,
2000. Ozone
levels are down as much as 40% in some areas. The protective level of ozone has
dropped below 200 dobson units in some areas. The area and population affected
including the Argentinean
city of Ushaia which has a population of 30,000 and Punta Arenas, Chile which
has a population of 120,000 are all at risk during this time period. The area will be under these conditions for the next
24-30 hours. The
public should avoid going outside during the peak hours of 11:00 a.m. and 3:00
p.m. to avoid exposure to the UV rays. If people do go outside during these
hours they should wear protective sunscreen and if possible a hat or head
covering and sunglasses with a uv rating.
 
Maps
of deviations represent total ozone deviations from the 1978-1988 level
estimated using TOMS data for all areas except the Antarctic and from the
pre-1980 level estimated using Dobson data over the Antarctic.
Ozone
Hole reaches South America again-
Dangerous
levels of UV rays bombard Chile and Argentina Humans, animals and plant
life all at risk of
exposure
October
7,2000-The Ozone hole has again reached land and
population areas in Argentina, Chile and The Falkland Islands. Ozone
levels are down as much as 40% in some areas. The protective level of ozone has
dropped below under 200 dobson units in some areas. The area and population affected
including the Argentinean
city of Ushaia which has a population of 30,000 and Punta Arenas, Chile which
has a population of 120,000 are all at risk during this time period. The area will be under these conditions for the next 30-40 hours.
In
Argentina the regional Secretary of Health is planning on implementing a system that will
give warnings of ozone levels and ultraviolet levels to the population. The
system will be similar to traffic signals.
The
public should avoid going outside during the peak hours of 11:00 a.m. and 3:00
p.m. to avoid exposure to the UV rays. If people do go outside during these
hours they should wear protective sunscreen and if possible a hat or head
covering and sunglasses with a uv rating.
The ozone layer in the upper atmosphere is the
key filter for damaging ultraviolet-B (UV-B) radiation in the Sun's rays.
Without it, organisms suffer extensive DNA damage, which in humans results in a
greater increase in the risk of skin cancer, eye cataracts and defects in the
body's immune system.
1 Dobson Unit
(DU) is defined to be 0.01 mm thickness
at STP (standard temperature and pressure). Ozone layer thickness is expressed
in terms of Dobson units, which measure what its physical thickness would be if
compressed in the Earth's atmosphere.
In
those terms, it's very thin indeed. A
normal range is 300 to 500 Dobson units, which translates to an eighth of an
inch-basically two stacked pennies.
In space, it's best not to envision the
ozone layer as a distinct, measurable band. Instead, think of it in terms of
parts per million concentrations in the stratosphere (the layer six to 30 miles
above the Earth's surface).
The unit is named after
G.M.B. Dobson, one of the first
scientists to investigate atmospheric ozone . He designed the 'Dobson ozone spectrophotometer' - the standard instrument used to measure ozone from the ground.
The Dobson spectrometer measures the intensity of solar UV radiation. A single measurement uses two
wavelengths of uv, but for normal operation pairs of readings are taken at two different wavelength settings
for a total of four
wavelengths, two of which are absorbed by ozone and two of which are
not.
Maps
of deviations represent total ozone deviations from the 1978-1988 level
estimated using TOMS data for all areas except the Antarctic and from the
pre-1980 level estimated using Dobson data over the Antarctic.
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