We earthlings have damaged the ozone layer with chemicals (called chlorofluorocarbons or CFCs) that are used in refrigerators and air conditioners. This has been proved by a long series of measurements from space and on the ground. In fact, the Nobel Prize in Chemistry has been awarded to three atmospheric scientists for having discovered and explained this link.

To our knowledge there are no studies concerning UV-B effects on penguins. As their eyes are exposed to a lot of UV due to the high reflectivity of snow and a marked enhancement during the ozone hole, investigation into the impact on penguins is desirable. The fact that penguins are visual predators, eating krill or fish in the water column, would make any eye damage an important issue for survival. See similar questions...

Significant reductions in ozone content in the stratosphere above the Arctic have been observed during the late winter and early spring (January-March) in 6 of the last 9 years. However, these reductions, typically 20-25%, are much smaller than those observed currently each spring over the Antarctic (the ozone hole). The difference between ozone content in the two polar regions (see figure below) is caused by dissimilar weather patterns. See similar questions...

First, it's important to know that ozone plays two different roles in the atmosphere. At ground level, "bad ozone" is a pollutant caused by human activities; it's a major component of health-damaging smog. The same chemical occurs naturally in the stratosphere, and this "good ozone" acts as a shield, filtering out most of the ultraviolet light from the Sun that could otherwise prove deadly to people, animals, and plants. See similar questions...

The "ozone hole" is a loss of stratospheric ozone in springtime over Antarctica, peaking in September. The ozone hole area is defined as the size of the region with total ozone below 220 Dobson units (DU). Dobson Units are a unit of measurement that refer to the thickness of the ozone layer in a vertical column from the surface to the top of the atmosphere, a quantity called the "total column ozone amount." Prior to 1979, total column ozone values over Antarctica never fell below 220 DU. See similar questions...

The observed average amount of ozone during September, October, and November over the British Antarctic Survey station at Halley, Antarctica, first revealed notable decreases in the early 1980s, compared with the preceding data obtained starting in 1957. The ozone hole is formed each year when there is a sharp decline (currently up to 60%) in the total ozone over most of Antarctica for a period of about three months (September-November) during spring in the Southern Hemisphere. See similar questions...

No, they are two different (but related) issues.The greenhouse effect issue concerns the warming of the lower part of the atmosphere, the troposphere (the layer in which temperature drops with height; it is about 10-15 kilometers thick, varying with latitude and season), by increasing concentrations of the so-called greenhouse gases (carbon dioxide, methane, nitrous oxide, ozone, and others) in the troposphere. See similar questions...

It isn't really a "hole", but a large decrease in the total amount of ozone overhead. It is truly a large decrease over Antarctica at certain times of the year, but there are significant general reductions in ozone elsewhere, including the Northern Hemisphere. The "hole" and the general reductions elsewhere are not getting better yet. We expect that things will improve, starting early in the next century. See similar questions...

If possible, you might try thickening your medium. You can also try using a smaller applicator tip, or even a regulator valve for use with thinner materials. For additional information please read the pdf on use instructions. See similar questions...

Ever since the link between CFCs and ozone depletion was proposed in 1974, skeptics have attacked the science behind the link and the policies of controlling CFCs and other ozone depleting substances. We have compiled a detailed analysis of the arguments of the skeptics. It is interesting to note how the skeptics are using the same bag of tricks to cast doubt upon the science behind the global warming debate, and the need to control greenhouse-effect gases. See similar questions...

Ozone depletion by human-produced CFCs was first hypothesized in 1974 (Molina and Rowland, 1974). The first evidence of ozone depletion was detected by ground-based instruments operated by the British Antarctic Survey at Halley Bay on the Antarctic coast in 1982. The results seemed so improbable that researchers collected data for three more years before finally publishing the first paper documenting the emergence of an ozone hole over Antarctica (Farman, 1985). See similar questions...

Abarca, J.F, and C.C. Casiccia, "Skin cancer and ultraviolet-B radiation under the Antarctic ozone hole: southern Chile, 1987-2000," Photodermatology, Photoimmunology & Photomedicine, 18, 294, 2002. Farman, J.C., B.D. Gardner and J.D. Shanklin, "Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx Interaction, Nature, 315, 207-210, 1985. Manins, P., R. Allan, T. Beer, P. Fraser, P. Holper, R. Suppiah, R. and K. Walsh. See similar questions...

The term ozone "hole" refers to a large and rapid decrease in the abundance of ozone molecules, not the complete absence of them. The Antarctic ozone "hole" occurs during the southern spring between September and November. See similar questions...

Hollow heart" is a discoloured hole sometimes found in the center of an otherwise healthy potato. It can be caused by rapid growth, extremes in watering, or drought in the farm field. A hollow heart potato can be eaten, but to improve its appearance the hollow piece should be cut out. See similar questions...

Reading holes are areas within the field of an antenna where no reading is possible and can occur close to an antenna because of: Because of the physics, the RF field does not couple equally with the tag in all locations. It is possible for a tag to be close to the antenna in some orientations and still not be read. It is possible for mutual de-tuning to occur, when the size of the tag's antenna is of similar size to the reader's antenna. This could occur with an antenna designed for a printer. See similar questions...